diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-mlxbf.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-mlxbf.c | 2496 |
1 files changed, 2496 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-mlxbf.c b/drivers/i2c/busses/i2c-mlxbf.c new file mode 100644 index 000000000..90c488a60 --- /dev/null +++ b/drivers/i2c/busses/i2c-mlxbf.c @@ -0,0 +1,2496 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Mellanox BlueField I2C bus driver + * + * Copyright (C) 2020 Mellanox Technologies, Ltd. + */ + +#include <linux/acpi.h> +#include <linux/bitfield.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/interrupt.h> +#include <linux/i2c.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/string.h> + +/* Defines what functionality is present. */ +#define MLXBF_I2C_FUNC_SMBUS_BLOCK \ + (I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL) + +#define MLXBF_I2C_FUNC_SMBUS_DEFAULT \ + (I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA | \ + I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_I2C_BLOCK | \ + I2C_FUNC_SMBUS_PROC_CALL) + +#define MLXBF_I2C_FUNC_ALL \ + (MLXBF_I2C_FUNC_SMBUS_DEFAULT | MLXBF_I2C_FUNC_SMBUS_BLOCK | \ + I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SLAVE) + +#define MLXBF_I2C_SMBUS_MAX 3 + +/* Shared resources info in BlueField platforms. */ + +#define MLXBF_I2C_COALESCE_TYU_ADDR 0x02801300 +#define MLXBF_I2C_COALESCE_TYU_SIZE 0x010 + +#define MLXBF_I2C_GPIO_TYU_ADDR 0x02802000 +#define MLXBF_I2C_GPIO_TYU_SIZE 0x100 + +#define MLXBF_I2C_COREPLL_TYU_ADDR 0x02800358 +#define MLXBF_I2C_COREPLL_TYU_SIZE 0x008 + +#define MLXBF_I2C_COREPLL_YU_ADDR 0x02800c30 +#define MLXBF_I2C_COREPLL_YU_SIZE 0x00c + +#define MLXBF_I2C_SHARED_RES_MAX 3 + +/* + * Note that the following SMBus, CAUSE, GPIO and PLL register addresses + * refer to their respective offsets relative to the corresponding + * memory-mapped region whose addresses are specified in either the DT or + * the ACPI tables or above. + */ + +/* + * SMBus Master core clock frequency. Timing configurations are + * strongly dependent on the core clock frequency of the SMBus + * Master. Default value is set to 400MHz. + */ +#define MLXBF_I2C_TYU_PLL_OUT_FREQ (400 * 1000 * 1000) +/* Reference clock for Bluefield - 156 MHz. */ +#define MLXBF_I2C_PLL_IN_FREQ 156250000ULL + +/* Constant used to determine the PLL frequency. */ +#define MLNXBF_I2C_COREPLL_CONST 16384ULL + +#define MLXBF_I2C_FREQUENCY_1GHZ 1000000000ULL + +/* PLL registers. */ +#define MLXBF_I2C_CORE_PLL_REG1 0x4 +#define MLXBF_I2C_CORE_PLL_REG2 0x8 + +/* OR cause register. */ +#define MLXBF_I2C_CAUSE_OR_EVTEN0 0x14 +#define MLXBF_I2C_CAUSE_OR_CLEAR 0x18 + +/* Arbiter Cause Register. */ +#define MLXBF_I2C_CAUSE_ARBITER 0x1c + +/* + * Cause Status flags. Note that those bits might be considered + * as interrupt enabled bits. + */ + +/* Transaction ended with STOP. */ +#define MLXBF_I2C_CAUSE_TRANSACTION_ENDED BIT(0) +/* Master arbitration lost. */ +#define MLXBF_I2C_CAUSE_M_ARBITRATION_LOST BIT(1) +/* Unexpected start detected. */ +#define MLXBF_I2C_CAUSE_UNEXPECTED_START BIT(2) +/* Unexpected stop detected. */ +#define MLXBF_I2C_CAUSE_UNEXPECTED_STOP BIT(3) +/* Wait for transfer continuation. */ +#define MLXBF_I2C_CAUSE_WAIT_FOR_FW_DATA BIT(4) +/* Failed to generate STOP. */ +#define MLXBF_I2C_CAUSE_PUT_STOP_FAILED BIT(5) +/* Failed to generate START. */ +#define MLXBF_I2C_CAUSE_PUT_START_FAILED BIT(6) +/* Clock toggle completed. */ +#define MLXBF_I2C_CAUSE_CLK_TOGGLE_DONE BIT(7) +/* Transfer timeout occurred. */ +#define MLXBF_I2C_CAUSE_M_FW_TIMEOUT BIT(8) +/* Master busy bit reset. */ +#define MLXBF_I2C_CAUSE_M_GW_BUSY_FALL BIT(9) + +#define MLXBF_I2C_CAUSE_MASTER_ARBITER_BITS_MASK GENMASK(9, 0) + +#define MLXBF_I2C_CAUSE_MASTER_STATUS_ERROR \ + (MLXBF_I2C_CAUSE_M_ARBITRATION_LOST | \ + MLXBF_I2C_CAUSE_UNEXPECTED_START | \ + MLXBF_I2C_CAUSE_UNEXPECTED_STOP | \ + MLXBF_I2C_CAUSE_PUT_STOP_FAILED | \ + MLXBF_I2C_CAUSE_PUT_START_FAILED | \ + MLXBF_I2C_CAUSE_CLK_TOGGLE_DONE | \ + MLXBF_I2C_CAUSE_M_FW_TIMEOUT) + +/* + * Slave cause status flags. Note that those bits might be considered + * as interrupt enabled bits. + */ + +/* Write transaction received successfully. */ +#define MLXBF_I2C_CAUSE_WRITE_SUCCESS BIT(0) +/* Read transaction received, waiting for response. */ +#define MLXBF_I2C_CAUSE_READ_WAIT_FW_RESPONSE BIT(13) +/* Slave busy bit reset. */ +#define MLXBF_I2C_CAUSE_S_GW_BUSY_FALL BIT(18) + +#define MLXBF_I2C_CAUSE_SLAVE_ARBITER_BITS_MASK GENMASK(20, 0) + +/* Cause coalesce registers. */ +#define MLXBF_I2C_CAUSE_COALESCE_0 0x00 +#define MLXBF_I2C_CAUSE_COALESCE_1 0x04 +#define MLXBF_I2C_CAUSE_COALESCE_2 0x08 + +#define MLXBF_I2C_CAUSE_TYU_SLAVE_BIT MLXBF_I2C_SMBUS_MAX +#define MLXBF_I2C_CAUSE_YU_SLAVE_BIT 1 + +/* Functional enable register. */ +#define MLXBF_I2C_GPIO_0_FUNC_EN_0 0x28 +/* Force OE enable register. */ +#define MLXBF_I2C_GPIO_0_FORCE_OE_EN 0x30 +/* + * Note that Smbus GWs are on GPIOs 30:25. Two pins are used to control + * SDA/SCL lines: + * + * SMBUS GW0 -> bits[26:25] + * SMBUS GW1 -> bits[28:27] + * SMBUS GW2 -> bits[30:29] + */ +#define MLXBF_I2C_GPIO_SMBUS_GW_PINS(num) (25 + ((num) << 1)) + +/* Note that gw_id can be 0,1 or 2. */ +#define MLXBF_I2C_GPIO_SMBUS_GW_MASK(num) \ + (0xffffffff & (~(0x3 << MLXBF_I2C_GPIO_SMBUS_GW_PINS(num)))) + +#define MLXBF_I2C_GPIO_SMBUS_GW_RESET_PINS(num, val) \ + ((val) & MLXBF_I2C_GPIO_SMBUS_GW_MASK(num)) + +#define MLXBF_I2C_GPIO_SMBUS_GW_ASSERT_PINS(num, val) \ + ((val) | (0x3 << MLXBF_I2C_GPIO_SMBUS_GW_PINS(num))) + +/* SMBus timing parameters. */ +#define MLXBF_I2C_SMBUS_TIMER_SCL_LOW_SCL_HIGH 0x00 +#define MLXBF_I2C_SMBUS_TIMER_FALL_RISE_SPIKE 0x04 +#define MLXBF_I2C_SMBUS_TIMER_THOLD 0x08 +#define MLXBF_I2C_SMBUS_TIMER_TSETUP_START_STOP 0x0c +#define MLXBF_I2C_SMBUS_TIMER_TSETUP_DATA 0x10 +#define MLXBF_I2C_SMBUS_THIGH_MAX_TBUF 0x14 +#define MLXBF_I2C_SMBUS_SCL_LOW_TIMEOUT 0x18 + +enum { + MLXBF_I2C_TIMING_100KHZ = 100000, + MLXBF_I2C_TIMING_400KHZ = 400000, + MLXBF_I2C_TIMING_1000KHZ = 1000000, +}; + +/* + * Defines SMBus operating frequency and core clock frequency. + * According to ADB files, default values are compliant to 100KHz SMBus + * @ 400MHz core clock. The driver should be able to calculate core + * frequency based on PLL parameters. + */ +#define MLXBF_I2C_COREPLL_FREQ MLXBF_I2C_TYU_PLL_OUT_FREQ + +/* Core PLL TYU configuration. */ +#define MLXBF_I2C_COREPLL_CORE_F_TYU_MASK GENMASK(15, 3) +#define MLXBF_I2C_COREPLL_CORE_OD_TYU_MASK GENMASK(19, 16) +#define MLXBF_I2C_COREPLL_CORE_R_TYU_MASK GENMASK(25, 20) + +/* Core PLL YU configuration. */ +#define MLXBF_I2C_COREPLL_CORE_F_YU_MASK GENMASK(25, 0) +#define MLXBF_I2C_COREPLL_CORE_OD_YU_MASK GENMASK(3, 0) +#define MLXBF_I2C_COREPLL_CORE_R_YU_MASK GENMASK(31, 26) + + +/* Core PLL frequency. */ +static u64 mlxbf_i2c_corepll_frequency; + +/* SMBus Master GW. */ +#define MLXBF_I2C_SMBUS_MASTER_GW 0x200 +/* Number of bytes received and sent. */ +#define MLXBF_I2C_SMBUS_RS_BYTES 0x300 +/* Packet error check (PEC) value. */ +#define MLXBF_I2C_SMBUS_MASTER_PEC 0x304 +/* Status bits (ACK/NACK/FW Timeout). */ +#define MLXBF_I2C_SMBUS_MASTER_STATUS 0x308 +/* SMbus Master Finite State Machine. */ +#define MLXBF_I2C_SMBUS_MASTER_FSM 0x310 + +/* + * When enabled, the master will issue a stop condition in case of + * timeout while waiting for FW response. + */ +#define MLXBF_I2C_SMBUS_EN_FW_TIMEOUT 0x31c + +/* SMBus master GW control bits offset in MLXBF_I2C_SMBUS_MASTER_GW[31:3]. */ +#define MLXBF_I2C_MASTER_LOCK_BIT BIT(31) /* Lock bit. */ +#define MLXBF_I2C_MASTER_BUSY_BIT BIT(30) /* Busy bit. */ +#define MLXBF_I2C_MASTER_START_BIT BIT(29) /* Control start. */ +#define MLXBF_I2C_MASTER_CTL_WRITE_BIT BIT(28) /* Control write phase. */ +#define MLXBF_I2C_MASTER_CTL_READ_BIT BIT(19) /* Control read phase. */ +#define MLXBF_I2C_MASTER_STOP_BIT BIT(3) /* Control stop. */ + +#define MLXBF_I2C_MASTER_ENABLE \ + (MLXBF_I2C_MASTER_LOCK_BIT | MLXBF_I2C_MASTER_BUSY_BIT | \ + MLXBF_I2C_MASTER_START_BIT | MLXBF_I2C_MASTER_STOP_BIT) + +#define MLXBF_I2C_MASTER_ENABLE_WRITE \ + (MLXBF_I2C_MASTER_ENABLE | MLXBF_I2C_MASTER_CTL_WRITE_BIT) + +#define MLXBF_I2C_MASTER_ENABLE_READ \ + (MLXBF_I2C_MASTER_ENABLE | MLXBF_I2C_MASTER_CTL_READ_BIT) + +#define MLXBF_I2C_MASTER_SLV_ADDR_SHIFT 12 /* Slave address shift. */ +#define MLXBF_I2C_MASTER_WRITE_SHIFT 21 /* Control write bytes shift. */ +#define MLXBF_I2C_MASTER_SEND_PEC_SHIFT 20 /* Send PEC byte shift. */ +#define MLXBF_I2C_MASTER_PARSE_EXP_SHIFT 11 /* Parse expected bytes shift. */ +#define MLXBF_I2C_MASTER_READ_SHIFT 4 /* Control read bytes shift. */ + +/* SMBus master GW Data descriptor. */ +#define MLXBF_I2C_MASTER_DATA_DESC_ADDR 0x280 +#define MLXBF_I2C_MASTER_DATA_DESC_SIZE 0x80 /* Size in bytes. */ + +/* Maximum bytes to read/write per SMBus transaction. */ +#define MLXBF_I2C_MASTER_DATA_R_LENGTH MLXBF_I2C_MASTER_DATA_DESC_SIZE +#define MLXBF_I2C_MASTER_DATA_W_LENGTH (MLXBF_I2C_MASTER_DATA_DESC_SIZE - 1) + +/* All bytes were transmitted. */ +#define MLXBF_I2C_SMBUS_STATUS_BYTE_CNT_DONE BIT(0) +/* NACK received. */ +#define MLXBF_I2C_SMBUS_STATUS_NACK_RCV BIT(1) +/* Slave's byte count >128 bytes. */ +#define MLXBF_I2C_SMBUS_STATUS_READ_ERR BIT(2) +/* Timeout occurred. */ +#define MLXBF_I2C_SMBUS_STATUS_FW_TIMEOUT BIT(3) + +#define MLXBF_I2C_SMBUS_MASTER_STATUS_MASK GENMASK(3, 0) + +#define MLXBF_I2C_SMBUS_MASTER_STATUS_ERROR \ + (MLXBF_I2C_SMBUS_STATUS_NACK_RCV | \ + MLXBF_I2C_SMBUS_STATUS_READ_ERR | \ + MLXBF_I2C_SMBUS_STATUS_FW_TIMEOUT) + +#define MLXBF_I2C_SMBUS_MASTER_FSM_STOP_MASK BIT(31) +#define MLXBF_I2C_SMBUS_MASTER_FSM_PS_STATE_MASK BIT(15) + +/* SMBus slave GW. */ +#define MLXBF_I2C_SMBUS_SLAVE_GW 0x400 +/* Number of bytes received and sent from/to master. */ +#define MLXBF_I2C_SMBUS_SLAVE_RS_MASTER_BYTES 0x500 +/* Packet error check (PEC) value. */ +#define MLXBF_I2C_SMBUS_SLAVE_PEC 0x504 +/* SMBus slave Finite State Machine (FSM). */ +#define MLXBF_I2C_SMBUS_SLAVE_FSM 0x510 +/* + * Should be set when all raised causes handled, and cleared by HW on + * every new cause. + */ +#define MLXBF_I2C_SMBUS_SLAVE_READY 0x52c + +/* SMBus slave GW control bits offset in MLXBF_I2C_SMBUS_SLAVE_GW[31:19]. */ +#define MLXBF_I2C_SLAVE_BUSY_BIT BIT(30) /* Busy bit. */ +#define MLXBF_I2C_SLAVE_WRITE_BIT BIT(29) /* Control write enable. */ + +#define MLXBF_I2C_SLAVE_ENABLE \ + (MLXBF_I2C_SLAVE_BUSY_BIT | MLXBF_I2C_SLAVE_WRITE_BIT) + +#define MLXBF_I2C_SLAVE_WRITE_BYTES_SHIFT 22 /* Number of bytes to write. */ +#define MLXBF_I2C_SLAVE_SEND_PEC_SHIFT 21 /* Send PEC byte shift. */ + +/* SMBus slave GW Data descriptor. */ +#define MLXBF_I2C_SLAVE_DATA_DESC_ADDR 0x480 +#define MLXBF_I2C_SLAVE_DATA_DESC_SIZE 0x80 /* Size in bytes. */ + +/* SMbus slave configuration registers. */ +#define MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG 0x514 +#define MLXBF_I2C_SMBUS_SLAVE_ADDR_CNT 16 +#define MLXBF_I2C_SMBUS_SLAVE_ADDR_EN_BIT 7 +#define MLXBF_I2C_SMBUS_SLAVE_ADDR_MASK GENMASK(6, 0) + +#define MLXBF_I2C_SLAVE_ADDR_ENABLED(addr) \ + ((addr) & (1 << MLXBF_I2C_SMBUS_SLAVE_ADDR_EN_BIT)) + +/* + * Timeout is given in microsends. Note also that timeout handling is not + * exact. + */ +#define MLXBF_I2C_SMBUS_TIMEOUT (300 * 1000) /* 300ms */ +#define MLXBF_I2C_SMBUS_LOCK_POLL_TIMEOUT (300 * 1000) /* 300ms */ + +/* Encapsulates timing parameters. */ +struct mlxbf_i2c_timings { + u16 scl_high; /* Clock high period. */ + u16 scl_low; /* Clock low period. */ + u8 sda_rise; /* Data rise time. */ + u8 sda_fall; /* Data fall time. */ + u8 scl_rise; /* Clock rise time. */ + u8 scl_fall; /* Clock fall time. */ + u16 hold_start; /* Hold time after (REPEATED) START. */ + u16 hold_data; /* Data hold time. */ + u16 setup_start; /* REPEATED START condition setup time. */ + u16 setup_stop; /* STOP condition setup time. */ + u16 setup_data; /* Data setup time. */ + u16 pad; /* Padding. */ + u16 buf; /* Bus free time between STOP and START. */ + u16 thigh_max; /* Thigh max. */ + u32 timeout; /* Detect clock low timeout. */ +}; + +enum { + MLXBF_I2C_F_READ = BIT(0), + MLXBF_I2C_F_WRITE = BIT(1), + MLXBF_I2C_F_NORESTART = BIT(3), + MLXBF_I2C_F_SMBUS_OPERATION = BIT(4), + MLXBF_I2C_F_SMBUS_BLOCK = BIT(5), + MLXBF_I2C_F_SMBUS_PEC = BIT(6), + MLXBF_I2C_F_SMBUS_PROCESS_CALL = BIT(7), +}; + +struct mlxbf_i2c_smbus_operation { + u32 flags; + u32 length; /* Buffer length in bytes. */ + u8 *buffer; +}; + +#define MLXBF_I2C_SMBUS_OP_CNT_1 1 +#define MLXBF_I2C_SMBUS_OP_CNT_2 2 +#define MLXBF_I2C_SMBUS_OP_CNT_3 3 +#define MLXBF_I2C_SMBUS_MAX_OP_CNT MLXBF_I2C_SMBUS_OP_CNT_3 + +struct mlxbf_i2c_smbus_request { + u8 slave; + u8 operation_cnt; + struct mlxbf_i2c_smbus_operation operation[MLXBF_I2C_SMBUS_MAX_OP_CNT]; +}; + +struct mlxbf_i2c_resource { + void __iomem *io; + struct resource *params; + struct mutex *lock; /* Mutex to protect mlxbf_i2c_resource. */ + u8 type; +}; + +/* List of chip resources that are being accessed by the driver. */ +enum { + MLXBF_I2C_SMBUS_RES, + MLXBF_I2C_MST_CAUSE_RES, + MLXBF_I2C_SLV_CAUSE_RES, + MLXBF_I2C_COALESCE_RES, + MLXBF_I2C_COREPLL_RES, + MLXBF_I2C_GPIO_RES, + MLXBF_I2C_END_RES, +}; + +/* Helper macro to define an I2C resource parameters. */ +#define MLXBF_I2C_RES_PARAMS(addr, size, str) \ + { \ + .start = (addr), \ + .end = (addr) + (size) - 1, \ + .name = (str) \ + } + +static struct resource mlxbf_i2c_coalesce_tyu_params = + MLXBF_I2C_RES_PARAMS(MLXBF_I2C_COALESCE_TYU_ADDR, + MLXBF_I2C_COALESCE_TYU_SIZE, + "COALESCE_MEM"); +static struct resource mlxbf_i2c_corepll_tyu_params = + MLXBF_I2C_RES_PARAMS(MLXBF_I2C_COREPLL_TYU_ADDR, + MLXBF_I2C_COREPLL_TYU_SIZE, + "COREPLL_MEM"); +static struct resource mlxbf_i2c_corepll_yu_params = + MLXBF_I2C_RES_PARAMS(MLXBF_I2C_COREPLL_YU_ADDR, + MLXBF_I2C_COREPLL_YU_SIZE, + "COREPLL_MEM"); +static struct resource mlxbf_i2c_gpio_tyu_params = + MLXBF_I2C_RES_PARAMS(MLXBF_I2C_GPIO_TYU_ADDR, + MLXBF_I2C_GPIO_TYU_SIZE, + "GPIO_MEM"); + +static struct mutex mlxbf_i2c_coalesce_lock; +static struct mutex mlxbf_i2c_corepll_lock; +static struct mutex mlxbf_i2c_gpio_lock; + +/* Mellanox BlueField chip type. */ +enum mlxbf_i2c_chip_type { + MLXBF_I2C_CHIP_TYPE_1, /* Mellanox BlueField-1 chip. */ + MLXBF_I2C_CHIP_TYPE_2, /* Mallanox BlueField-2 chip. */ +}; + +struct mlxbf_i2c_chip_info { + enum mlxbf_i2c_chip_type type; + /* Chip shared resources that are being used by the I2C controller. */ + struct mlxbf_i2c_resource *shared_res[MLXBF_I2C_SHARED_RES_MAX]; + + /* Callback to calculate the core PLL frequency. */ + u64 (*calculate_freq)(struct mlxbf_i2c_resource *corepll_res); +}; + +struct mlxbf_i2c_priv { + const struct mlxbf_i2c_chip_info *chip; + struct i2c_adapter adap; + struct mlxbf_i2c_resource *smbus; + struct mlxbf_i2c_resource *mst_cause; + struct mlxbf_i2c_resource *slv_cause; + struct mlxbf_i2c_resource *coalesce; + u64 frequency; /* Core frequency in Hz. */ + int bus; /* Physical bus identifier. */ + int irq; + struct i2c_client *slave; +}; + +static struct mlxbf_i2c_resource mlxbf_i2c_coalesce_res[] = { + [MLXBF_I2C_CHIP_TYPE_1] = { + .params = &mlxbf_i2c_coalesce_tyu_params, + .lock = &mlxbf_i2c_coalesce_lock, + .type = MLXBF_I2C_COALESCE_RES + }, + {} +}; + +static struct mlxbf_i2c_resource mlxbf_i2c_corepll_res[] = { + [MLXBF_I2C_CHIP_TYPE_1] = { + .params = &mlxbf_i2c_corepll_tyu_params, + .lock = &mlxbf_i2c_corepll_lock, + .type = MLXBF_I2C_COREPLL_RES + }, + [MLXBF_I2C_CHIP_TYPE_2] = { + .params = &mlxbf_i2c_corepll_yu_params, + .lock = &mlxbf_i2c_corepll_lock, + .type = MLXBF_I2C_COREPLL_RES, + } +}; + +static struct mlxbf_i2c_resource mlxbf_i2c_gpio_res[] = { + [MLXBF_I2C_CHIP_TYPE_1] = { + .params = &mlxbf_i2c_gpio_tyu_params, + .lock = &mlxbf_i2c_gpio_lock, + .type = MLXBF_I2C_GPIO_RES + }, + {} +}; + +static u8 mlxbf_i2c_bus_count; + +static struct mutex mlxbf_i2c_bus_lock; + +/* Polling frequency in microseconds. */ +#define MLXBF_I2C_POLL_FREQ_IN_USEC 200 + +#define MLXBF_I2C_SHIFT_0 0 +#define MLXBF_I2C_SHIFT_8 8 +#define MLXBF_I2C_SHIFT_16 16 +#define MLXBF_I2C_SHIFT_24 24 + +#define MLXBF_I2C_MASK_8 GENMASK(7, 0) +#define MLXBF_I2C_MASK_16 GENMASK(15, 0) + +/* + * Function to poll a set of bits at a specific address; it checks whether + * the bits are equal to zero when eq_zero is set to 'true', and not equal + * to zero when eq_zero is set to 'false'. + * Note that the timeout is given in microseconds. + */ +static u32 mlxbf_smbus_poll(void __iomem *io, u32 addr, u32 mask, + bool eq_zero, u32 timeout) +{ + u32 bits; + + timeout = (timeout / MLXBF_I2C_POLL_FREQ_IN_USEC) + 1; + + do { + bits = readl(io + addr) & mask; + if (eq_zero ? bits == 0 : bits != 0) + return eq_zero ? 1 : bits; + udelay(MLXBF_I2C_POLL_FREQ_IN_USEC); + } while (timeout-- != 0); + + return 0; +} + +/* + * SW must make sure that the SMBus Master GW is idle before starting + * a transaction. Accordingly, this function polls the Master FSM stop + * bit; it returns false when the bit is asserted, true if not. + */ +static bool mlxbf_smbus_master_wait_for_idle(struct mlxbf_i2c_priv *priv) +{ + u32 mask = MLXBF_I2C_SMBUS_MASTER_FSM_STOP_MASK; + u32 addr = MLXBF_I2C_SMBUS_MASTER_FSM; + u32 timeout = MLXBF_I2C_SMBUS_TIMEOUT; + + if (mlxbf_smbus_poll(priv->smbus->io, addr, mask, true, timeout)) + return true; + + return false; +} + +/* + * wait for the lock to be released before acquiring it. + */ +static bool mlxbf_i2c_smbus_master_lock(struct mlxbf_i2c_priv *priv) +{ + if (mlxbf_smbus_poll(priv->smbus->io, MLXBF_I2C_SMBUS_MASTER_GW, + MLXBF_I2C_MASTER_LOCK_BIT, true, + MLXBF_I2C_SMBUS_LOCK_POLL_TIMEOUT)) + return true; + + return false; +} + +static void mlxbf_i2c_smbus_master_unlock(struct mlxbf_i2c_priv *priv) +{ + /* Clear the gw to clear the lock */ + writel(0, priv->smbus->io + MLXBF_I2C_SMBUS_MASTER_GW); +} + +static bool mlxbf_i2c_smbus_transaction_success(u32 master_status, + u32 cause_status) +{ + /* + * When transaction ended with STOP, all bytes were transmitted, + * and no NACK received, then the transaction ended successfully. + * On the other hand, when the GW is configured with the stop bit + * de-asserted then the SMBus expects the following GW configuration + * for transfer continuation. + */ + if ((cause_status & MLXBF_I2C_CAUSE_WAIT_FOR_FW_DATA) || + ((cause_status & MLXBF_I2C_CAUSE_TRANSACTION_ENDED) && + (master_status & MLXBF_I2C_SMBUS_STATUS_BYTE_CNT_DONE) && + !(master_status & MLXBF_I2C_SMBUS_STATUS_NACK_RCV))) + return true; + + return false; +} + +/* + * Poll SMBus master status and return transaction status, + * i.e. whether succeeded or failed. I2C and SMBus fault codes + * are returned as negative numbers from most calls, with zero + * or some positive number indicating a non-fault return. + */ +static int mlxbf_i2c_smbus_check_status(struct mlxbf_i2c_priv *priv) +{ + u32 master_status_bits; + u32 cause_status_bits; + + /* + * GW busy bit is raised by the driver and cleared by the HW + * when the transaction is completed. The busy bit is a good + * indicator of transaction status. So poll the busy bit, and + * then read the cause and master status bits to determine if + * errors occurred during the transaction. + */ + mlxbf_smbus_poll(priv->smbus->io, MLXBF_I2C_SMBUS_MASTER_GW, + MLXBF_I2C_MASTER_BUSY_BIT, true, + MLXBF_I2C_SMBUS_TIMEOUT); + + /* Read cause status bits. */ + cause_status_bits = readl(priv->mst_cause->io + + MLXBF_I2C_CAUSE_ARBITER); + cause_status_bits &= MLXBF_I2C_CAUSE_MASTER_ARBITER_BITS_MASK; + + /* + * Parse both Cause and Master GW bits, then return transaction status. + */ + + master_status_bits = readl(priv->smbus->io + + MLXBF_I2C_SMBUS_MASTER_STATUS); + master_status_bits &= MLXBF_I2C_SMBUS_MASTER_STATUS_MASK; + + if (mlxbf_i2c_smbus_transaction_success(master_status_bits, + cause_status_bits)) + return 0; + + /* + * In case of timeout on GW busy, the ISR will clear busy bit but + * transaction ended bits cause will not be set so the transaction + * fails. Then, we must check Master GW status bits. + */ + if ((master_status_bits & MLXBF_I2C_SMBUS_MASTER_STATUS_ERROR) && + (cause_status_bits & (MLXBF_I2C_CAUSE_TRANSACTION_ENDED | + MLXBF_I2C_CAUSE_M_GW_BUSY_FALL))) + return -EIO; + + if (cause_status_bits & MLXBF_I2C_CAUSE_MASTER_STATUS_ERROR) + return -EAGAIN; + + return -ETIMEDOUT; +} + +static void mlxbf_i2c_smbus_write_data(struct mlxbf_i2c_priv *priv, + const u8 *data, u8 length, u32 addr) +{ + u8 offset, aligned_length; + u32 data32; + + aligned_length = round_up(length, 4); + + /* + * Copy data bytes from 4-byte aligned source buffer. + * Data copied to the Master GW Data Descriptor MUST be shifted + * left so the data starts at the MSB of the descriptor registers + * as required by the underlying hardware. Enable byte swapping + * when writing data bytes to the 32 * 32-bit HW Data registers + * a.k.a Master GW Data Descriptor. + */ + for (offset = 0; offset < aligned_length; offset += sizeof(u32)) { + data32 = *((u32 *)(data + offset)); + iowrite32be(data32, priv->smbus->io + addr + offset); + } +} + +static void mlxbf_i2c_smbus_read_data(struct mlxbf_i2c_priv *priv, + u8 *data, u8 length, u32 addr) +{ + u32 data32, mask; + u8 byte, offset; + + mask = sizeof(u32) - 1; + + /* + * Data bytes in the Master GW Data Descriptor are shifted left + * so the data starts at the MSB of the descriptor registers as + * set by the underlying hardware. Enable byte swapping while + * reading data bytes from the 32 * 32-bit HW Data registers + * a.k.a Master GW Data Descriptor. + */ + + for (offset = 0; offset < (length & ~mask); offset += sizeof(u32)) { + data32 = ioread32be(priv->smbus->io + addr + offset); + *((u32 *)(data + offset)) = data32; + } + + if (!(length & mask)) + return; + + data32 = ioread32be(priv->smbus->io + addr + offset); + + for (byte = 0; byte < (length & mask); byte++) { + data[offset + byte] = data32 & GENMASK(7, 0); + data32 = ror32(data32, MLXBF_I2C_SHIFT_8); + } +} + +static int mlxbf_i2c_smbus_enable(struct mlxbf_i2c_priv *priv, u8 slave, + u8 len, u8 block_en, u8 pec_en, bool read) +{ + u32 command; + + /* Set Master GW control word. */ + if (read) { + command = MLXBF_I2C_MASTER_ENABLE_READ; + command |= rol32(len, MLXBF_I2C_MASTER_READ_SHIFT); + } else { + command = MLXBF_I2C_MASTER_ENABLE_WRITE; + command |= rol32(len, MLXBF_I2C_MASTER_WRITE_SHIFT); + } + command |= rol32(slave, MLXBF_I2C_MASTER_SLV_ADDR_SHIFT); + command |= rol32(block_en, MLXBF_I2C_MASTER_PARSE_EXP_SHIFT); + command |= rol32(pec_en, MLXBF_I2C_MASTER_SEND_PEC_SHIFT); + + /* Clear status bits. */ + writel(0x0, priv->smbus->io + MLXBF_I2C_SMBUS_MASTER_STATUS); + /* Set the cause data. */ + writel(~0x0, priv->mst_cause->io + MLXBF_I2C_CAUSE_OR_CLEAR); + /* Zero PEC byte. */ + writel(0x0, priv->smbus->io + MLXBF_I2C_SMBUS_MASTER_PEC); + /* Zero byte count. */ + writel(0x0, priv->smbus->io + MLXBF_I2C_SMBUS_RS_BYTES); + + /* GW activation. */ + writel(command, priv->smbus->io + MLXBF_I2C_SMBUS_MASTER_GW); + + /* + * Poll master status and check status bits. An ACK is sent when + * completing writing data to the bus (Master 'byte_count_done' bit + * is set to 1). + */ + return mlxbf_i2c_smbus_check_status(priv); +} + +static int +mlxbf_i2c_smbus_start_transaction(struct mlxbf_i2c_priv *priv, + struct mlxbf_i2c_smbus_request *request) +{ + u8 data_desc[MLXBF_I2C_MASTER_DATA_DESC_SIZE] = { 0 }; + u8 op_idx, data_idx, data_len, write_len, read_len; + struct mlxbf_i2c_smbus_operation *operation; + u8 read_en, write_en, block_en, pec_en; + u8 slave, flags, addr; + u8 *read_buf; + int ret = 0; + + if (request->operation_cnt > MLXBF_I2C_SMBUS_MAX_OP_CNT) + return -EINVAL; + + read_buf = NULL; + data_idx = 0; + read_en = 0; + write_en = 0; + write_len = 0; + read_len = 0; + block_en = 0; + pec_en = 0; + slave = request->slave & GENMASK(6, 0); + addr = slave << 1; + + /* + * Try to acquire the smbus gw lock before any reads of the GW register since + * a read sets the lock. + */ + if (WARN_ON(!mlxbf_i2c_smbus_master_lock(priv))) + return -EBUSY; + + /* Check whether the HW is idle */ + if (WARN_ON(!mlxbf_smbus_master_wait_for_idle(priv))) { + ret = -EBUSY; + goto out_unlock; + } + + /* Set first byte. */ + data_desc[data_idx++] = addr; + + for (op_idx = 0; op_idx < request->operation_cnt; op_idx++) { + operation = &request->operation[op_idx]; + flags = operation->flags; + + /* + * Note that read and write operations might be handled by a + * single command. If the MLXBF_I2C_F_SMBUS_OPERATION is set + * then write command byte and set the optional SMBus specific + * bits such as block_en and pec_en. These bits MUST be + * submitted by the first operation only. + */ + if (op_idx == 0 && flags & MLXBF_I2C_F_SMBUS_OPERATION) { + block_en = flags & MLXBF_I2C_F_SMBUS_BLOCK; + pec_en = flags & MLXBF_I2C_F_SMBUS_PEC; + } + + if (flags & MLXBF_I2C_F_WRITE) { + write_en = 1; + write_len += operation->length; + if (data_idx + operation->length > + MLXBF_I2C_MASTER_DATA_DESC_SIZE) { + ret = -ENOBUFS; + goto out_unlock; + } + memcpy(data_desc + data_idx, + operation->buffer, operation->length); + data_idx += operation->length; + } + /* + * We assume that read operations are performed only once per + * SMBus transaction. *TBD* protect this statement so it won't + * be executed twice? or return an error if we try to read more + * than once? + */ + if (flags & MLXBF_I2C_F_READ) { + read_en = 1; + /* Subtract 1 as required by HW. */ + read_len = operation->length - 1; + read_buf = operation->buffer; + } + } + + /* Set Master GW data descriptor. */ + data_len = write_len + 1; /* Add one byte of the slave address. */ + /* + * Note that data_len cannot be 0. Indeed, the slave address byte + * must be written to the data registers. + */ + mlxbf_i2c_smbus_write_data(priv, (const u8 *)data_desc, data_len, + MLXBF_I2C_MASTER_DATA_DESC_ADDR); + + if (write_en) { + ret = mlxbf_i2c_smbus_enable(priv, slave, write_len, block_en, + pec_en, 0); + if (ret) + goto out_unlock; + } + + if (read_en) { + /* Write slave address to Master GW data descriptor. */ + mlxbf_i2c_smbus_write_data(priv, (const u8 *)&addr, 1, + MLXBF_I2C_MASTER_DATA_DESC_ADDR); + ret = mlxbf_i2c_smbus_enable(priv, slave, read_len, block_en, + pec_en, 1); + if (!ret) { + /* Get Master GW data descriptor. */ + mlxbf_i2c_smbus_read_data(priv, data_desc, read_len + 1, + MLXBF_I2C_MASTER_DATA_DESC_ADDR); + + /* Get data from Master GW data descriptor. */ + memcpy(read_buf, data_desc, read_len + 1); + } + + /* + * After a read operation the SMBus FSM ps (present state) + * needs to be 'manually' reset. This should be removed in + * next tag integration. + */ + writel(MLXBF_I2C_SMBUS_MASTER_FSM_PS_STATE_MASK, + priv->smbus->io + MLXBF_I2C_SMBUS_MASTER_FSM); + } + +out_unlock: + mlxbf_i2c_smbus_master_unlock(priv); + + return ret; +} + +/* I2C SMBus protocols. */ + +static void +mlxbf_i2c_smbus_quick_command(struct mlxbf_i2c_smbus_request *request, + u8 read) +{ + request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_1; + + request->operation[0].length = 0; + request->operation[0].flags = MLXBF_I2C_F_WRITE; + request->operation[0].flags |= read ? MLXBF_I2C_F_READ : 0; +} + +static void mlxbf_i2c_smbus_byte_func(struct mlxbf_i2c_smbus_request *request, + u8 *data, bool read, bool pec_check) +{ + request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_1; + + request->operation[0].length = 1; + request->operation[0].length += pec_check; + + request->operation[0].flags = MLXBF_I2C_F_SMBUS_OPERATION; + request->operation[0].flags |= read ? + MLXBF_I2C_F_READ : MLXBF_I2C_F_WRITE; + request->operation[0].flags |= pec_check ? MLXBF_I2C_F_SMBUS_PEC : 0; + + request->operation[0].buffer = data; +} + +static void +mlxbf_i2c_smbus_data_byte_func(struct mlxbf_i2c_smbus_request *request, + u8 *command, u8 *data, bool read, bool pec_check) +{ + request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_2; + + request->operation[0].length = 1; + request->operation[0].flags = + MLXBF_I2C_F_SMBUS_OPERATION | MLXBF_I2C_F_WRITE; + request->operation[0].flags |= pec_check ? MLXBF_I2C_F_SMBUS_PEC : 0; + request->operation[0].buffer = command; + + request->operation[1].length = 1; + request->operation[1].length += pec_check; + request->operation[1].flags = read ? + MLXBF_I2C_F_READ : MLXBF_I2C_F_WRITE; + request->operation[1].buffer = data; +} + +static void +mlxbf_i2c_smbus_data_word_func(struct mlxbf_i2c_smbus_request *request, + u8 *command, u8 *data, bool read, bool pec_check) +{ + request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_2; + + request->operation[0].length = 1; + request->operation[0].flags = + MLXBF_I2C_F_SMBUS_OPERATION | MLXBF_I2C_F_WRITE; + request->operation[0].flags |= pec_check ? MLXBF_I2C_F_SMBUS_PEC : 0; + request->operation[0].buffer = command; + + request->operation[1].length = 2; + request->operation[1].length += pec_check; + request->operation[1].flags = read ? + MLXBF_I2C_F_READ : MLXBF_I2C_F_WRITE; + request->operation[1].buffer = data; +} + +static void +mlxbf_i2c_smbus_i2c_block_func(struct mlxbf_i2c_smbus_request *request, + u8 *command, u8 *data, u8 *data_len, bool read, + bool pec_check) +{ + request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_2; + + request->operation[0].length = 1; + request->operation[0].flags = + MLXBF_I2C_F_SMBUS_OPERATION | MLXBF_I2C_F_WRITE; + request->operation[0].flags |= pec_check ? MLXBF_I2C_F_SMBUS_PEC : 0; + request->operation[0].buffer = command; + + /* + * As specified in the standard, the max number of bytes to read/write + * per block operation is 32 bytes. In Golan code, the controller can + * read up to 128 bytes and write up to 127 bytes. + */ + request->operation[1].length = + (*data_len + pec_check > I2C_SMBUS_BLOCK_MAX) ? + I2C_SMBUS_BLOCK_MAX : *data_len + pec_check; + request->operation[1].flags = read ? + MLXBF_I2C_F_READ : MLXBF_I2C_F_WRITE; + /* + * Skip the first data byte, which corresponds to the number of bytes + * to read/write. + */ + request->operation[1].buffer = data + 1; + + *data_len = request->operation[1].length; + + /* Set the number of byte to read. This will be used by userspace. */ + if (read) + data[0] = *data_len; +} + +static void mlxbf_i2c_smbus_block_func(struct mlxbf_i2c_smbus_request *request, + u8 *command, u8 *data, u8 *data_len, + bool read, bool pec_check) +{ + request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_2; + + request->operation[0].length = 1; + request->operation[0].flags = + MLXBF_I2C_F_SMBUS_OPERATION | MLXBF_I2C_F_WRITE; + request->operation[0].flags |= MLXBF_I2C_F_SMBUS_BLOCK; + request->operation[0].flags |= pec_check ? MLXBF_I2C_F_SMBUS_PEC : 0; + request->operation[0].buffer = command; + + request->operation[1].length = + (*data_len + pec_check > I2C_SMBUS_BLOCK_MAX) ? + I2C_SMBUS_BLOCK_MAX : *data_len + pec_check; + request->operation[1].flags = read ? + MLXBF_I2C_F_READ : MLXBF_I2C_F_WRITE; + request->operation[1].buffer = data + 1; + + *data_len = request->operation[1].length; + + /* Set the number of bytes to read. This will be used by userspace. */ + if (read) + data[0] = *data_len; +} + +static void +mlxbf_i2c_smbus_process_call_func(struct mlxbf_i2c_smbus_request *request, + u8 *command, u8 *data, bool pec_check) +{ + request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_3; + + request->operation[0].length = 1; + request->operation[0].flags = + MLXBF_I2C_F_SMBUS_OPERATION | MLXBF_I2C_F_WRITE; + request->operation[0].flags |= MLXBF_I2C_F_SMBUS_BLOCK; + request->operation[0].flags |= pec_check ? MLXBF_I2C_F_SMBUS_PEC : 0; + request->operation[0].buffer = command; + + request->operation[1].length = 2; + request->operation[1].flags = MLXBF_I2C_F_WRITE; + request->operation[1].buffer = data; + + request->operation[2].length = 3; + request->operation[2].flags = MLXBF_I2C_F_READ; + request->operation[2].buffer = data; +} + +static void +mlxbf_i2c_smbus_blk_process_call_func(struct mlxbf_i2c_smbus_request *request, + u8 *command, u8 *data, u8 *data_len, + bool pec_check) +{ + u32 length; + + request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_3; + + request->operation[0].length = 1; + request->operation[0].flags = + MLXBF_I2C_F_SMBUS_OPERATION | MLXBF_I2C_F_WRITE; + request->operation[0].flags |= MLXBF_I2C_F_SMBUS_BLOCK; + request->operation[0].flags |= (pec_check) ? MLXBF_I2C_F_SMBUS_PEC : 0; + request->operation[0].buffer = command; + + length = (*data_len + pec_check > I2C_SMBUS_BLOCK_MAX) ? + I2C_SMBUS_BLOCK_MAX : *data_len + pec_check; + + request->operation[1].length = length - pec_check; + request->operation[1].flags = MLXBF_I2C_F_WRITE; + request->operation[1].buffer = data; + + request->operation[2].length = length; + request->operation[2].flags = MLXBF_I2C_F_READ; + request->operation[2].buffer = data; + + *data_len = length; /* including PEC byte. */ +} + +/* Initialization functions. */ + +static bool mlxbf_i2c_has_chip_type(struct mlxbf_i2c_priv *priv, u8 type) +{ + return priv->chip->type == type; +} + +static struct mlxbf_i2c_resource * +mlxbf_i2c_get_shared_resource(struct mlxbf_i2c_priv *priv, u8 type) +{ + const struct mlxbf_i2c_chip_info *chip = priv->chip; + struct mlxbf_i2c_resource *res; + u8 res_idx = 0; + + for (res_idx = 0; res_idx < MLXBF_I2C_SHARED_RES_MAX; res_idx++) { + res = chip->shared_res[res_idx]; + if (res && res->type == type) + return res; + } + + return NULL; +} + +static int mlxbf_i2c_init_resource(struct platform_device *pdev, + struct mlxbf_i2c_resource **res, + u8 type) +{ + struct mlxbf_i2c_resource *tmp_res; + struct device *dev = &pdev->dev; + + if (!res || *res || type >= MLXBF_I2C_END_RES) + return -EINVAL; + + tmp_res = devm_kzalloc(dev, sizeof(struct mlxbf_i2c_resource), + GFP_KERNEL); + if (!tmp_res) + return -ENOMEM; + + tmp_res->params = platform_get_resource(pdev, IORESOURCE_MEM, type); + if (!tmp_res->params) { + devm_kfree(dev, tmp_res); + return -EIO; + } + + tmp_res->io = devm_ioremap_resource(dev, tmp_res->params); + if (IS_ERR(tmp_res->io)) { + devm_kfree(dev, tmp_res); + return PTR_ERR(tmp_res->io); + } + + tmp_res->type = type; + + *res = tmp_res; + + return 0; +} + +static u32 mlxbf_i2c_get_ticks(struct mlxbf_i2c_priv *priv, u64 nanoseconds, + bool minimum) +{ + u64 frequency; + u32 ticks; + + /* + * Compute ticks as follow: + * + * Ticks + * Time = --------- x 10^9 => Ticks = Time x Frequency x 10^-9 + * Frequency + */ + frequency = priv->frequency; + ticks = (nanoseconds * frequency) / MLXBF_I2C_FREQUENCY_1GHZ; + /* + * The number of ticks is rounded down and if minimum is equal to 1 + * then add one tick. + */ + if (minimum) + ticks++; + + return ticks; +} + +static u32 mlxbf_i2c_set_timer(struct mlxbf_i2c_priv *priv, u64 nsec, bool opt, + u32 mask, u8 shift) +{ + u32 val = (mlxbf_i2c_get_ticks(priv, nsec, opt) & mask) << shift; + + return val; +} + +static void mlxbf_i2c_set_timings(struct mlxbf_i2c_priv *priv, + const struct mlxbf_i2c_timings *timings) +{ + u32 timer; + + timer = mlxbf_i2c_set_timer(priv, timings->scl_high, + false, MLXBF_I2C_MASK_16, + MLXBF_I2C_SHIFT_0); + timer |= mlxbf_i2c_set_timer(priv, timings->scl_low, + false, MLXBF_I2C_MASK_16, + MLXBF_I2C_SHIFT_16); + writel(timer, priv->smbus->io + + MLXBF_I2C_SMBUS_TIMER_SCL_LOW_SCL_HIGH); + + timer = mlxbf_i2c_set_timer(priv, timings->sda_rise, false, + MLXBF_I2C_MASK_8, MLXBF_I2C_SHIFT_0); + timer |= mlxbf_i2c_set_timer(priv, timings->sda_fall, false, + MLXBF_I2C_MASK_8, MLXBF_I2C_SHIFT_8); + timer |= mlxbf_i2c_set_timer(priv, timings->scl_rise, false, + MLXBF_I2C_MASK_8, MLXBF_I2C_SHIFT_16); + timer |= mlxbf_i2c_set_timer(priv, timings->scl_fall, false, + MLXBF_I2C_MASK_8, MLXBF_I2C_SHIFT_24); + writel(timer, priv->smbus->io + + MLXBF_I2C_SMBUS_TIMER_FALL_RISE_SPIKE); + + timer = mlxbf_i2c_set_timer(priv, timings->hold_start, true, + MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_0); + timer |= mlxbf_i2c_set_timer(priv, timings->hold_data, true, + MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_16); + writel(timer, priv->smbus->io + MLXBF_I2C_SMBUS_TIMER_THOLD); + + timer = mlxbf_i2c_set_timer(priv, timings->setup_start, true, + MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_0); + timer |= mlxbf_i2c_set_timer(priv, timings->setup_stop, true, + MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_16); + writel(timer, priv->smbus->io + + MLXBF_I2C_SMBUS_TIMER_TSETUP_START_STOP); + + timer = mlxbf_i2c_set_timer(priv, timings->setup_data, true, + MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_0); + writel(timer, priv->smbus->io + MLXBF_I2C_SMBUS_TIMER_TSETUP_DATA); + + timer = mlxbf_i2c_set_timer(priv, timings->buf, false, + MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_0); + timer |= mlxbf_i2c_set_timer(priv, timings->thigh_max, false, + MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_16); + writel(timer, priv->smbus->io + MLXBF_I2C_SMBUS_THIGH_MAX_TBUF); + + timer = timings->timeout; + writel(timer, priv->smbus->io + MLXBF_I2C_SMBUS_SCL_LOW_TIMEOUT); +} + +enum mlxbf_i2c_timings_config { + MLXBF_I2C_TIMING_CONFIG_100KHZ, + MLXBF_I2C_TIMING_CONFIG_400KHZ, + MLXBF_I2C_TIMING_CONFIG_1000KHZ, +}; + +/* + * Note that the mlxbf_i2c_timings->timeout value is not related to the + * bus frequency, it is impacted by the time it takes the driver to + * complete data transmission before transaction abort. + */ +static const struct mlxbf_i2c_timings mlxbf_i2c_timings[] = { + [MLXBF_I2C_TIMING_CONFIG_100KHZ] = { + .scl_high = 4810, + .scl_low = 5000, + .hold_start = 4000, + .setup_start = 4800, + .setup_stop = 4000, + .setup_data = 250, + .sda_rise = 50, + .sda_fall = 50, + .scl_rise = 50, + .scl_fall = 50, + .hold_data = 300, + .buf = 20000, + .thigh_max = 5000, + .timeout = 106500 + }, + [MLXBF_I2C_TIMING_CONFIG_400KHZ] = { + .scl_high = 1011, + .scl_low = 1300, + .hold_start = 600, + .setup_start = 700, + .setup_stop = 600, + .setup_data = 100, + .sda_rise = 50, + .sda_fall = 50, + .scl_rise = 50, + .scl_fall = 50, + .hold_data = 300, + .buf = 20000, + .thigh_max = 5000, + .timeout = 106500 + }, + [MLXBF_I2C_TIMING_CONFIG_1000KHZ] = { + .scl_high = 600, + .scl_low = 1300, + .hold_start = 600, + .setup_start = 600, + .setup_stop = 600, + .setup_data = 100, + .sda_rise = 50, + .sda_fall = 50, + .scl_rise = 50, + .scl_fall = 50, + .hold_data = 300, + .buf = 20000, + .thigh_max = 5000, + .timeout = 106500 + } +}; + +static int mlxbf_i2c_init_timings(struct platform_device *pdev, + struct mlxbf_i2c_priv *priv) +{ + enum mlxbf_i2c_timings_config config_idx; + struct device *dev = &pdev->dev; + u32 config_khz; + + int ret; + + ret = device_property_read_u32(dev, "clock-frequency", &config_khz); + if (ret < 0) + config_khz = MLXBF_I2C_TIMING_100KHZ; + + switch (config_khz) { + default: + /* Default settings is 100 KHz. */ + pr_warn("Illegal value %d: defaulting to 100 KHz\n", + config_khz); + fallthrough; + case MLXBF_I2C_TIMING_100KHZ: + config_idx = MLXBF_I2C_TIMING_CONFIG_100KHZ; + break; + + case MLXBF_I2C_TIMING_400KHZ: + config_idx = MLXBF_I2C_TIMING_CONFIG_400KHZ; + break; + + case MLXBF_I2C_TIMING_1000KHZ: + config_idx = MLXBF_I2C_TIMING_CONFIG_1000KHZ; + break; + } + + mlxbf_i2c_set_timings(priv, &mlxbf_i2c_timings[config_idx]); + + return 0; +} + +static int mlxbf_i2c_get_gpio(struct platform_device *pdev, + struct mlxbf_i2c_priv *priv) +{ + struct mlxbf_i2c_resource *gpio_res; + struct device *dev = &pdev->dev; + struct resource *params; + resource_size_t size; + + gpio_res = mlxbf_i2c_get_shared_resource(priv, MLXBF_I2C_GPIO_RES); + if (!gpio_res) + return -EPERM; + + /* + * The GPIO region in TYU space is shared among I2C busses. + * This function MUST be serialized to avoid racing when + * claiming the memory region and/or setting up the GPIO. + */ + lockdep_assert_held(gpio_res->lock); + + /* Check whether the memory map exist. */ + if (gpio_res->io) + return 0; + + params = gpio_res->params; + size = resource_size(params); + + if (!devm_request_mem_region(dev, params->start, size, params->name)) + return -EFAULT; + + gpio_res->io = devm_ioremap(dev, params->start, size); + if (!gpio_res->io) { + devm_release_mem_region(dev, params->start, size); + return -ENOMEM; + } + + return 0; +} + +static int mlxbf_i2c_release_gpio(struct platform_device *pdev, + struct mlxbf_i2c_priv *priv) +{ + struct mlxbf_i2c_resource *gpio_res; + struct device *dev = &pdev->dev; + struct resource *params; + + gpio_res = mlxbf_i2c_get_shared_resource(priv, MLXBF_I2C_GPIO_RES); + if (!gpio_res) + return 0; + + mutex_lock(gpio_res->lock); + + if (gpio_res->io) { + /* Release the GPIO resource. */ + params = gpio_res->params; + devm_iounmap(dev, gpio_res->io); + devm_release_mem_region(dev, params->start, + resource_size(params)); + } + + mutex_unlock(gpio_res->lock); + + return 0; +} + +static int mlxbf_i2c_get_corepll(struct platform_device *pdev, + struct mlxbf_i2c_priv *priv) +{ + struct mlxbf_i2c_resource *corepll_res; + struct device *dev = &pdev->dev; + struct resource *params; + resource_size_t size; + + corepll_res = mlxbf_i2c_get_shared_resource(priv, + MLXBF_I2C_COREPLL_RES); + if (!corepll_res) + return -EPERM; + + /* + * The COREPLL region in TYU space is shared among I2C busses. + * This function MUST be serialized to avoid racing when + * claiming the memory region. + */ + lockdep_assert_held(corepll_res->lock); + + /* Check whether the memory map exist. */ + if (corepll_res->io) + return 0; + + params = corepll_res->params; + size = resource_size(params); + + if (!devm_request_mem_region(dev, params->start, size, params->name)) + return -EFAULT; + + corepll_res->io = devm_ioremap(dev, params->start, size); + if (!corepll_res->io) { + devm_release_mem_region(dev, params->start, size); + return -ENOMEM; + } + + return 0; +} + +static int mlxbf_i2c_release_corepll(struct platform_device *pdev, + struct mlxbf_i2c_priv *priv) +{ + struct mlxbf_i2c_resource *corepll_res; + struct device *dev = &pdev->dev; + struct resource *params; + + corepll_res = mlxbf_i2c_get_shared_resource(priv, + MLXBF_I2C_COREPLL_RES); + + mutex_lock(corepll_res->lock); + + if (corepll_res->io) { + /* Release the CorePLL resource. */ + params = corepll_res->params; + devm_iounmap(dev, corepll_res->io); + devm_release_mem_region(dev, params->start, + resource_size(params)); + } + + mutex_unlock(corepll_res->lock); + + return 0; +} + +static int mlxbf_i2c_init_master(struct platform_device *pdev, + struct mlxbf_i2c_priv *priv) +{ + struct mlxbf_i2c_resource *gpio_res; + struct device *dev = &pdev->dev; + u32 config_reg; + int ret; + + /* This configuration is only needed for BlueField 1. */ + if (!mlxbf_i2c_has_chip_type(priv, MLXBF_I2C_CHIP_TYPE_1)) + return 0; + + gpio_res = mlxbf_i2c_get_shared_resource(priv, MLXBF_I2C_GPIO_RES); + if (!gpio_res) + return -EPERM; + + /* + * The GPIO region in TYU space is shared among I2C busses. + * This function MUST be serialized to avoid racing when + * claiming the memory region and/or setting up the GPIO. + */ + + mutex_lock(gpio_res->lock); + + ret = mlxbf_i2c_get_gpio(pdev, priv); + if (ret < 0) { + dev_err(dev, "Failed to get gpio resource"); + mutex_unlock(gpio_res->lock); + return ret; + } + + /* + * TYU - Configuration for GPIO pins. Those pins must be asserted in + * MLXBF_I2C_GPIO_0_FUNC_EN_0, i.e. GPIO 0 is controlled by HW, and must + * be reset in MLXBF_I2C_GPIO_0_FORCE_OE_EN, i.e. GPIO_OE will be driven + * instead of HW_OE. + * For now, we do not reset the GPIO state when the driver is removed. + * First, it is not necessary to disable the bus since we are using + * the same busses. Then, some busses might be shared among Linux and + * platform firmware; disabling the bus might compromise the system + * functionality. + */ + config_reg = readl(gpio_res->io + MLXBF_I2C_GPIO_0_FUNC_EN_0); + config_reg = MLXBF_I2C_GPIO_SMBUS_GW_ASSERT_PINS(priv->bus, + config_reg); + writel(config_reg, gpio_res->io + MLXBF_I2C_GPIO_0_FUNC_EN_0); + + config_reg = readl(gpio_res->io + MLXBF_I2C_GPIO_0_FORCE_OE_EN); + config_reg = MLXBF_I2C_GPIO_SMBUS_GW_RESET_PINS(priv->bus, + config_reg); + writel(config_reg, gpio_res->io + MLXBF_I2C_GPIO_0_FORCE_OE_EN); + + mutex_unlock(gpio_res->lock); + + return 0; +} + +static u64 mlxbf_i2c_calculate_freq_from_tyu(struct mlxbf_i2c_resource *corepll_res) +{ + u64 core_frequency; + u8 core_od, core_r; + u32 corepll_val; + u16 core_f; + + corepll_val = readl(corepll_res->io + MLXBF_I2C_CORE_PLL_REG1); + + /* Get Core PLL configuration bits. */ + core_f = FIELD_GET(MLXBF_I2C_COREPLL_CORE_F_TYU_MASK, corepll_val); + core_od = FIELD_GET(MLXBF_I2C_COREPLL_CORE_OD_TYU_MASK, corepll_val); + core_r = FIELD_GET(MLXBF_I2C_COREPLL_CORE_R_TYU_MASK, corepll_val); + + /* + * Compute PLL output frequency as follow: + * + * CORE_F + 1 + * PLL_OUT_FREQ = PLL_IN_FREQ * ---------------------------- + * (CORE_R + 1) * (CORE_OD + 1) + * + * Where PLL_OUT_FREQ and PLL_IN_FREQ refer to CoreFrequency + * and PadFrequency, respectively. + */ + core_frequency = MLXBF_I2C_PLL_IN_FREQ * (++core_f); + core_frequency /= (++core_r) * (++core_od); + + return core_frequency; +} + +static u64 mlxbf_i2c_calculate_freq_from_yu(struct mlxbf_i2c_resource *corepll_res) +{ + u32 corepll_reg1_val, corepll_reg2_val; + u64 corepll_frequency; + u8 core_od, core_r; + u32 core_f; + + corepll_reg1_val = readl(corepll_res->io + MLXBF_I2C_CORE_PLL_REG1); + corepll_reg2_val = readl(corepll_res->io + MLXBF_I2C_CORE_PLL_REG2); + + /* Get Core PLL configuration bits */ + core_f = FIELD_GET(MLXBF_I2C_COREPLL_CORE_F_YU_MASK, corepll_reg1_val); + core_r = FIELD_GET(MLXBF_I2C_COREPLL_CORE_R_YU_MASK, corepll_reg1_val); + core_od = FIELD_GET(MLXBF_I2C_COREPLL_CORE_OD_YU_MASK, corepll_reg2_val); + + /* + * Compute PLL output frequency as follow: + * + * CORE_F / 16384 + * PLL_OUT_FREQ = PLL_IN_FREQ * ---------------------------- + * (CORE_R + 1) * (CORE_OD + 1) + * + * Where PLL_OUT_FREQ and PLL_IN_FREQ refer to CoreFrequency + * and PadFrequency, respectively. + */ + corepll_frequency = (MLXBF_I2C_PLL_IN_FREQ * core_f) / MLNXBF_I2C_COREPLL_CONST; + corepll_frequency /= (++core_r) * (++core_od); + + return corepll_frequency; +} + +static int mlxbf_i2c_calculate_corepll_freq(struct platform_device *pdev, + struct mlxbf_i2c_priv *priv) +{ + const struct mlxbf_i2c_chip_info *chip = priv->chip; + struct mlxbf_i2c_resource *corepll_res; + struct device *dev = &pdev->dev; + u64 *freq = &priv->frequency; + int ret; + + corepll_res = mlxbf_i2c_get_shared_resource(priv, + MLXBF_I2C_COREPLL_RES); + if (!corepll_res) + return -EPERM; + + /* + * First, check whether the TYU core Clock frequency is set. + * The TYU core frequency is the same for all I2C busses; when + * the first device gets probed the frequency is determined and + * stored into a globally visible variable. So, first of all, + * check whether the frequency is already set. Here, we assume + * that the frequency is expected to be greater than 0. + */ + mutex_lock(corepll_res->lock); + if (!mlxbf_i2c_corepll_frequency) { + if (!chip->calculate_freq) { + mutex_unlock(corepll_res->lock); + return -EPERM; + } + + ret = mlxbf_i2c_get_corepll(pdev, priv); + if (ret < 0) { + dev_err(dev, "Failed to get corePLL resource"); + mutex_unlock(corepll_res->lock); + return ret; + } + + mlxbf_i2c_corepll_frequency = chip->calculate_freq(corepll_res); + } + mutex_unlock(corepll_res->lock); + + *freq = mlxbf_i2c_corepll_frequency; + + return 0; +} + +static int mlxbf_slave_enable(struct mlxbf_i2c_priv *priv, u8 addr) +{ + u32 slave_reg, slave_reg_tmp, slave_reg_avail, slave_addr_mask; + u8 reg, reg_cnt, byte, addr_tmp, reg_avail, byte_avail; + bool avail, disabled; + + disabled = false; + avail = false; + + if (!priv) + return -EPERM; + + reg_cnt = MLXBF_I2C_SMBUS_SLAVE_ADDR_CNT >> 2; + slave_addr_mask = MLXBF_I2C_SMBUS_SLAVE_ADDR_MASK; + + /* + * Read the slave registers. There are 4 * 32-bit slave registers. + * Each slave register can hold up to 4 * 8-bit slave configuration + * (7-bit address, 1 status bit (1 if enabled, 0 if not)). + */ + for (reg = 0; reg < reg_cnt; reg++) { + slave_reg = readl(priv->smbus->io + + MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG + reg * 0x4); + /* + * Each register holds 4 slave addresses. So, we have to keep + * the byte order consistent with the value read in order to + * update the register correctly, if needed. + */ + slave_reg_tmp = slave_reg; + for (byte = 0; byte < 4; byte++) { + addr_tmp = slave_reg_tmp & GENMASK(7, 0); + + /* + * Mark the first available slave address slot, i.e. its + * enabled bit should be unset. This slot might be used + * later on to register our slave. + */ + if (!avail && !MLXBF_I2C_SLAVE_ADDR_ENABLED(addr_tmp)) { + avail = true; + reg_avail = reg; + byte_avail = byte; + slave_reg_avail = slave_reg; + } + + /* + * Parse slave address bytes and check whether the + * slave address already exists and it's enabled, + * i.e. most significant bit is set. + */ + if ((addr_tmp & slave_addr_mask) == addr) { + if (MLXBF_I2C_SLAVE_ADDR_ENABLED(addr_tmp)) + return 0; + disabled = true; + break; + } + + /* Parse next byte. */ + slave_reg_tmp >>= 8; + } + + /* Exit the loop if the slave address is found. */ + if (disabled) + break; + } + + if (!avail && !disabled) + return -EINVAL; /* No room for a new slave address. */ + + if (avail && !disabled) { + reg = reg_avail; + byte = byte_avail; + /* Set the slave address. */ + slave_reg_avail &= ~(slave_addr_mask << (byte * 8)); + slave_reg_avail |= addr << (byte * 8); + slave_reg = slave_reg_avail; + } + + /* Enable the slave address and update the register. */ + slave_reg |= (1 << MLXBF_I2C_SMBUS_SLAVE_ADDR_EN_BIT) << (byte * 8); + writel(slave_reg, priv->smbus->io + MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG + + reg * 0x4); + + return 0; +} + +static int mlxbf_slave_disable(struct mlxbf_i2c_priv *priv) +{ + u32 slave_reg, slave_reg_tmp, slave_addr_mask; + u8 addr, addr_tmp, reg, reg_cnt, slave_byte; + struct i2c_client *client = priv->slave; + bool exist; + + exist = false; + + addr = client->addr; + reg_cnt = MLXBF_I2C_SMBUS_SLAVE_ADDR_CNT >> 2; + slave_addr_mask = MLXBF_I2C_SMBUS_SLAVE_ADDR_MASK; + + /* + * Read the slave registers. There are 4 * 32-bit slave registers. + * Each slave register can hold up to 4 * 8-bit slave configuration + * (7-bit address, 1 status bit (1 if enabled, 0 if not)). + */ + for (reg = 0; reg < reg_cnt; reg++) { + slave_reg = readl(priv->smbus->io + + MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG + reg * 0x4); + + /* Check whether the address slots are empty. */ + if (slave_reg == 0) + continue; + + /* + * Each register holds 4 slave addresses. So, we have to keep + * the byte order consistent with the value read in order to + * update the register correctly, if needed. + */ + slave_reg_tmp = slave_reg; + slave_byte = 0; + while (slave_reg_tmp != 0) { + addr_tmp = slave_reg_tmp & slave_addr_mask; + /* + * Parse slave address bytes and check whether the + * slave address already exists. + */ + if (addr_tmp == addr) { + exist = true; + break; + } + + /* Parse next byte. */ + slave_reg_tmp >>= 8; + slave_byte += 1; + } + + /* Exit the loop if the slave address is found. */ + if (exist) + break; + } + + if (!exist) + return 0; /* Slave is not registered, nothing to do. */ + + /* Cleanup the slave address slot. */ + slave_reg &= ~(GENMASK(7, 0) << (slave_byte * 8)); + writel(slave_reg, priv->smbus->io + MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG + + reg * 0x4); + + return 0; +} + +static int mlxbf_i2c_init_coalesce(struct platform_device *pdev, + struct mlxbf_i2c_priv *priv) +{ + struct mlxbf_i2c_resource *coalesce_res; + struct resource *params; + resource_size_t size; + int ret = 0; + + /* + * Unlike BlueField-1 platform, the coalesce registers is a dedicated + * resource in the next generations of BlueField. + */ + if (mlxbf_i2c_has_chip_type(priv, MLXBF_I2C_CHIP_TYPE_1)) { + coalesce_res = mlxbf_i2c_get_shared_resource(priv, + MLXBF_I2C_COALESCE_RES); + if (!coalesce_res) + return -EPERM; + + /* + * The Cause Coalesce group in TYU space is shared among + * I2C busses. This function MUST be serialized to avoid + * racing when claiming the memory region. + */ + lockdep_assert_held(mlxbf_i2c_gpio_res->lock); + + /* Check whether the memory map exist. */ + if (coalesce_res->io) { + priv->coalesce = coalesce_res; + return 0; + } + + params = coalesce_res->params; + size = resource_size(params); + + if (!request_mem_region(params->start, size, params->name)) + return -EFAULT; + + coalesce_res->io = ioremap(params->start, size); + if (!coalesce_res->io) { + release_mem_region(params->start, size); + return -ENOMEM; + } + + priv->coalesce = coalesce_res; + + } else { + ret = mlxbf_i2c_init_resource(pdev, &priv->coalesce, + MLXBF_I2C_COALESCE_RES); + } + + return ret; +} + +static int mlxbf_i2c_release_coalesce(struct platform_device *pdev, + struct mlxbf_i2c_priv *priv) +{ + struct mlxbf_i2c_resource *coalesce_res; + struct device *dev = &pdev->dev; + struct resource *params; + resource_size_t size; + + coalesce_res = priv->coalesce; + + if (coalesce_res->io) { + params = coalesce_res->params; + size = resource_size(params); + if (mlxbf_i2c_has_chip_type(priv, MLXBF_I2C_CHIP_TYPE_1)) { + mutex_lock(coalesce_res->lock); + iounmap(coalesce_res->io); + release_mem_region(params->start, size); + mutex_unlock(coalesce_res->lock); + } else { + devm_release_mem_region(dev, params->start, size); + } + } + + return 0; +} + +static int mlxbf_i2c_init_slave(struct platform_device *pdev, + struct mlxbf_i2c_priv *priv) +{ + struct device *dev = &pdev->dev; + u32 int_reg; + int ret; + + /* Reset FSM. */ + writel(0, priv->smbus->io + MLXBF_I2C_SMBUS_SLAVE_FSM); + + /* + * Enable slave cause interrupt bits. Drive + * MLXBF_I2C_CAUSE_READ_WAIT_FW_RESPONSE and + * MLXBF_I2C_CAUSE_WRITE_SUCCESS, these are enabled when an external + * masters issue a Read and Write, respectively. But, clear all + * interrupts first. + */ + writel(~0, priv->slv_cause->io + MLXBF_I2C_CAUSE_OR_CLEAR); + int_reg = MLXBF_I2C_CAUSE_READ_WAIT_FW_RESPONSE; + int_reg |= MLXBF_I2C_CAUSE_WRITE_SUCCESS; + writel(int_reg, priv->slv_cause->io + MLXBF_I2C_CAUSE_OR_EVTEN0); + + /* Finally, set the 'ready' bit to start handling transactions. */ + writel(0x1, priv->smbus->io + MLXBF_I2C_SMBUS_SLAVE_READY); + + /* Initialize the cause coalesce resource. */ + ret = mlxbf_i2c_init_coalesce(pdev, priv); + if (ret < 0) { + dev_err(dev, "failed to initialize cause coalesce\n"); + return ret; + } + + return 0; +} + +static bool mlxbf_i2c_has_coalesce(struct mlxbf_i2c_priv *priv, bool *read, + bool *write) +{ + const struct mlxbf_i2c_chip_info *chip = priv->chip; + u32 coalesce0_reg, cause_reg; + u8 slave_shift, is_set; + + *write = false; + *read = false; + + slave_shift = chip->type != MLXBF_I2C_CHIP_TYPE_1 ? + MLXBF_I2C_CAUSE_YU_SLAVE_BIT : + priv->bus + MLXBF_I2C_CAUSE_TYU_SLAVE_BIT; + + coalesce0_reg = readl(priv->coalesce->io + MLXBF_I2C_CAUSE_COALESCE_0); + is_set = coalesce0_reg & (1 << slave_shift); + + if (!is_set) + return false; + + /* Check the source of the interrupt, i.e. whether a Read or Write. */ + cause_reg = readl(priv->slv_cause->io + MLXBF_I2C_CAUSE_ARBITER); + if (cause_reg & MLXBF_I2C_CAUSE_READ_WAIT_FW_RESPONSE) + *read = true; + else if (cause_reg & MLXBF_I2C_CAUSE_WRITE_SUCCESS) + *write = true; + + /* Clear cause bits. */ + writel(~0x0, priv->slv_cause->io + MLXBF_I2C_CAUSE_OR_CLEAR); + + return true; +} + +static bool mlxbf_smbus_slave_wait_for_idle(struct mlxbf_i2c_priv *priv, + u32 timeout) +{ + u32 mask = MLXBF_I2C_CAUSE_S_GW_BUSY_FALL; + u32 addr = MLXBF_I2C_CAUSE_ARBITER; + + if (mlxbf_smbus_poll(priv->slv_cause->io, addr, mask, false, timeout)) + return true; + + return false; +} + +/* Send byte to 'external' smbus master. */ +static int mlxbf_smbus_irq_send(struct mlxbf_i2c_priv *priv, u8 recv_bytes) +{ + u8 data_desc[MLXBF_I2C_SLAVE_DATA_DESC_SIZE] = { 0 }; + u8 write_size, pec_en, addr, byte, value, byte_cnt, desc_size; + struct i2c_client *slave = priv->slave; + u32 control32, data32; + int ret; + + if (!slave) + return -EINVAL; + + addr = 0; + byte = 0; + desc_size = MLXBF_I2C_SLAVE_DATA_DESC_SIZE; + + /* + * Read bytes received from the external master. These bytes should + * be located in the first data descriptor register of the slave GW. + * These bytes are the slave address byte and the internal register + * address, if supplied. + */ + if (recv_bytes > 0) { + data32 = ioread32be(priv->smbus->io + + MLXBF_I2C_SLAVE_DATA_DESC_ADDR); + + /* Parse the received bytes. */ + switch (recv_bytes) { + case 2: + byte = (data32 >> 8) & GENMASK(7, 0); + fallthrough; + case 1: + addr = (data32 & GENMASK(7, 0)) >> 1; + } + + /* Check whether it's our slave address. */ + if (slave->addr != addr) + return -EINVAL; + } + + /* + * I2C read transactions may start by a WRITE followed by a READ. + * Indeed, most slave devices would expect the internal address + * following the slave address byte. So, write that byte first, + * and then, send the requested data bytes to the master. + */ + if (recv_bytes > 1) { + i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value); + value = byte; + ret = i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED, + &value); + i2c_slave_event(slave, I2C_SLAVE_STOP, &value); + + if (ret < 0) + return ret; + } + + /* + * Now, send data to the master; currently, the driver supports + * READ_BYTE, READ_WORD and BLOCK READ protocols. Note that the + * hardware can send up to 128 bytes per transfer. That is the + * size of its data registers. + */ + i2c_slave_event(slave, I2C_SLAVE_READ_REQUESTED, &value); + + for (byte_cnt = 0; byte_cnt < desc_size; byte_cnt++) { + data_desc[byte_cnt] = value; + i2c_slave_event(slave, I2C_SLAVE_READ_PROCESSED, &value); + } + + /* Send a stop condition to the backend. */ + i2c_slave_event(slave, I2C_SLAVE_STOP, &value); + + /* Handle the actual transfer. */ + + /* Set the number of bytes to write to master. */ + write_size = (byte_cnt - 1) & 0x7f; + + /* Write data to Slave GW data descriptor. */ + mlxbf_i2c_smbus_write_data(priv, data_desc, byte_cnt, + MLXBF_I2C_SLAVE_DATA_DESC_ADDR); + + pec_en = 0; /* Disable PEC since it is not supported. */ + + /* Prepare control word. */ + control32 = MLXBF_I2C_SLAVE_ENABLE; + control32 |= rol32(write_size, MLXBF_I2C_SLAVE_WRITE_BYTES_SHIFT); + control32 |= rol32(pec_en, MLXBF_I2C_SLAVE_SEND_PEC_SHIFT); + + writel(control32, priv->smbus->io + MLXBF_I2C_SMBUS_SLAVE_GW); + + /* + * Wait until the transfer is completed; the driver will wait + * until the GW is idle, a cause will rise on fall of GW busy. + */ + mlxbf_smbus_slave_wait_for_idle(priv, MLXBF_I2C_SMBUS_TIMEOUT); + + /* Release the Slave GW. */ + writel(0x0, priv->smbus->io + MLXBF_I2C_SMBUS_SLAVE_RS_MASTER_BYTES); + writel(0x0, priv->smbus->io + MLXBF_I2C_SMBUS_SLAVE_PEC); + writel(0x1, priv->smbus->io + MLXBF_I2C_SMBUS_SLAVE_READY); + + return 0; +} + +/* Receive bytes from 'external' smbus master. */ +static int mlxbf_smbus_irq_recv(struct mlxbf_i2c_priv *priv, u8 recv_bytes) +{ + u8 data_desc[MLXBF_I2C_SLAVE_DATA_DESC_SIZE] = { 0 }; + struct i2c_client *slave = priv->slave; + u8 value, byte, addr; + int ret = 0; + + if (!slave) + return -EINVAL; + + /* Read data from Slave GW data descriptor. */ + mlxbf_i2c_smbus_read_data(priv, data_desc, recv_bytes, + MLXBF_I2C_SLAVE_DATA_DESC_ADDR); + + /* Check whether its our slave address. */ + addr = data_desc[0] >> 1; + if (slave->addr != addr) + return -EINVAL; + + /* + * Notify the slave backend; another I2C master wants to write data + * to us. This event is sent once the slave address and the write bit + * is detected. + */ + i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value); + + /* Send the received data to the slave backend. */ + for (byte = 1; byte < recv_bytes; byte++) { + value = data_desc[byte]; + ret = i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED, + &value); + if (ret < 0) + break; + } + + /* Send a stop condition to the backend. */ + i2c_slave_event(slave, I2C_SLAVE_STOP, &value); + + /* Release the Slave GW. */ + writel(0x0, priv->smbus->io + MLXBF_I2C_SMBUS_SLAVE_RS_MASTER_BYTES); + writel(0x0, priv->smbus->io + MLXBF_I2C_SMBUS_SLAVE_PEC); + writel(0x1, priv->smbus->io + MLXBF_I2C_SMBUS_SLAVE_READY); + + return ret; +} + +static irqreturn_t mlxbf_smbus_irq(int irq, void *ptr) +{ + struct mlxbf_i2c_priv *priv = ptr; + bool read, write, irq_is_set; + u32 rw_bytes_reg; + u8 recv_bytes; + + /* + * Read TYU interrupt register and determine the source of the + * interrupt. Based on the source of the interrupt one of the + * following actions are performed: + * - Receive data and send response to master. + * - Send data and release slave GW. + * + * Handle read/write transaction only. CRmaster and Iarp requests + * are ignored for now. + */ + irq_is_set = mlxbf_i2c_has_coalesce(priv, &read, &write); + if (!irq_is_set || (!read && !write)) { + /* Nothing to do here, interrupt was not from this device. */ + return IRQ_NONE; + } + + /* + * The MLXBF_I2C_SMBUS_SLAVE_RS_MASTER_BYTES includes the number of + * bytes from/to master. These are defined by 8-bits each. If the lower + * 8 bits are set, then the master expect to read N bytes from the + * slave, if the higher 8 bits are sent then the slave expect N bytes + * from the master. + */ + rw_bytes_reg = readl(priv->smbus->io + + MLXBF_I2C_SMBUS_SLAVE_RS_MASTER_BYTES); + recv_bytes = (rw_bytes_reg >> 8) & GENMASK(7, 0); + + /* + * For now, the slave supports 128 bytes transfer. Discard remaining + * data bytes if the master wrote more than + * MLXBF_I2C_SLAVE_DATA_DESC_SIZE, i.e, the actual size of the slave + * data descriptor. + * + * Note that we will never expect to transfer more than 128 bytes; as + * specified in the SMBus standard, block transactions cannot exceed + * 32 bytes. + */ + recv_bytes = recv_bytes > MLXBF_I2C_SLAVE_DATA_DESC_SIZE ? + MLXBF_I2C_SLAVE_DATA_DESC_SIZE : recv_bytes; + + if (read) + mlxbf_smbus_irq_send(priv, recv_bytes); + else + mlxbf_smbus_irq_recv(priv, recv_bytes); + + return IRQ_HANDLED; +} + +/* Return negative errno on error. */ +static s32 mlxbf_i2c_smbus_xfer(struct i2c_adapter *adap, u16 addr, + unsigned short flags, char read_write, + u8 command, int size, + union i2c_smbus_data *data) +{ + struct mlxbf_i2c_smbus_request request = { 0 }; + struct mlxbf_i2c_priv *priv; + bool read, pec; + u8 byte_cnt; + + request.slave = addr; + + read = (read_write == I2C_SMBUS_READ); + pec = flags & I2C_FUNC_SMBUS_PEC; + + switch (size) { + case I2C_SMBUS_QUICK: + mlxbf_i2c_smbus_quick_command(&request, read); + dev_dbg(&adap->dev, "smbus quick, slave 0x%02x\n", addr); + break; + + case I2C_SMBUS_BYTE: + mlxbf_i2c_smbus_byte_func(&request, + read ? &data->byte : &command, read, + pec); + dev_dbg(&adap->dev, "smbus %s byte, slave 0x%02x.\n", + read ? "read" : "write", addr); + break; + + case I2C_SMBUS_BYTE_DATA: + mlxbf_i2c_smbus_data_byte_func(&request, &command, &data->byte, + read, pec); + dev_dbg(&adap->dev, "smbus %s byte data at 0x%02x, slave 0x%02x.\n", + read ? "read" : "write", command, addr); + break; + + case I2C_SMBUS_WORD_DATA: + mlxbf_i2c_smbus_data_word_func(&request, &command, + (u8 *)&data->word, read, pec); + dev_dbg(&adap->dev, "smbus %s word data at 0x%02x, slave 0x%02x.\n", + read ? "read" : "write", command, addr); + break; + + case I2C_SMBUS_I2C_BLOCK_DATA: + byte_cnt = data->block[0]; + mlxbf_i2c_smbus_i2c_block_func(&request, &command, data->block, + &byte_cnt, read, pec); + dev_dbg(&adap->dev, "i2c %s block data, %d bytes at 0x%02x, slave 0x%02x.\n", + read ? "read" : "write", byte_cnt, command, addr); + break; + + case I2C_SMBUS_BLOCK_DATA: + byte_cnt = read ? I2C_SMBUS_BLOCK_MAX : data->block[0]; + mlxbf_i2c_smbus_block_func(&request, &command, data->block, + &byte_cnt, read, pec); + dev_dbg(&adap->dev, "smbus %s block data, %d bytes at 0x%02x, slave 0x%02x.\n", + read ? "read" : "write", byte_cnt, command, addr); + break; + + case I2C_FUNC_SMBUS_PROC_CALL: + mlxbf_i2c_smbus_process_call_func(&request, &command, + (u8 *)&data->word, pec); + dev_dbg(&adap->dev, "process call, wr/rd at 0x%02x, slave 0x%02x.\n", + command, addr); + break; + + case I2C_FUNC_SMBUS_BLOCK_PROC_CALL: + byte_cnt = data->block[0]; + mlxbf_i2c_smbus_blk_process_call_func(&request, &command, + data->block, &byte_cnt, + pec); + dev_dbg(&adap->dev, "block process call, wr/rd %d bytes, slave 0x%02x.\n", + byte_cnt, addr); + break; + + default: + dev_dbg(&adap->dev, "Unsupported I2C/SMBus command %d\n", + size); + return -EOPNOTSUPP; + } + + priv = i2c_get_adapdata(adap); + + return mlxbf_i2c_smbus_start_transaction(priv, &request); +} + +static int mlxbf_i2c_reg_slave(struct i2c_client *slave) +{ + struct mlxbf_i2c_priv *priv = i2c_get_adapdata(slave->adapter); + int ret; + + if (priv->slave) + return -EBUSY; + + /* + * Do not support ten bit chip address and do not use Packet Error + * Checking (PEC). + */ + if (slave->flags & (I2C_CLIENT_TEN | I2C_CLIENT_PEC)) + return -EAFNOSUPPORT; + + ret = mlxbf_slave_enable(priv, slave->addr); + if (ret < 0) + return ret; + + priv->slave = slave; + + return 0; +} + +static int mlxbf_i2c_unreg_slave(struct i2c_client *slave) +{ + struct mlxbf_i2c_priv *priv = i2c_get_adapdata(slave->adapter); + int ret; + + WARN_ON(!priv->slave); + + /* Unregister slave, i.e. disable the slave address in hardware. */ + ret = mlxbf_slave_disable(priv); + if (ret < 0) + return ret; + + priv->slave = NULL; + + return 0; +} + +static u32 mlxbf_i2c_functionality(struct i2c_adapter *adap) +{ + return MLXBF_I2C_FUNC_ALL; +} + +static struct mlxbf_i2c_chip_info mlxbf_i2c_chip[] = { + [MLXBF_I2C_CHIP_TYPE_1] = { + .type = MLXBF_I2C_CHIP_TYPE_1, + .shared_res = { + [0] = &mlxbf_i2c_coalesce_res[MLXBF_I2C_CHIP_TYPE_1], + [1] = &mlxbf_i2c_corepll_res[MLXBF_I2C_CHIP_TYPE_1], + [2] = &mlxbf_i2c_gpio_res[MLXBF_I2C_CHIP_TYPE_1] + }, + .calculate_freq = mlxbf_i2c_calculate_freq_from_tyu + }, + [MLXBF_I2C_CHIP_TYPE_2] = { + .type = MLXBF_I2C_CHIP_TYPE_2, + .shared_res = { + [0] = &mlxbf_i2c_corepll_res[MLXBF_I2C_CHIP_TYPE_2] + }, + .calculate_freq = mlxbf_i2c_calculate_freq_from_yu + } +}; + +static const struct i2c_algorithm mlxbf_i2c_algo = { + .smbus_xfer = mlxbf_i2c_smbus_xfer, + .functionality = mlxbf_i2c_functionality, + .reg_slave = mlxbf_i2c_reg_slave, + .unreg_slave = mlxbf_i2c_unreg_slave, +}; + +static struct i2c_adapter_quirks mlxbf_i2c_quirks = { + .max_read_len = MLXBF_I2C_MASTER_DATA_R_LENGTH, + .max_write_len = MLXBF_I2C_MASTER_DATA_W_LENGTH, +}; + +static const struct of_device_id mlxbf_i2c_dt_ids[] = { + { + .compatible = "mellanox,i2c-mlxbf1", + .data = &mlxbf_i2c_chip[MLXBF_I2C_CHIP_TYPE_1] + }, + { + .compatible = "mellanox,i2c-mlxbf2", + .data = &mlxbf_i2c_chip[MLXBF_I2C_CHIP_TYPE_2] + }, + {}, +}; + +MODULE_DEVICE_TABLE(of, mlxbf_i2c_dt_ids); + +#ifdef CONFIG_ACPI +static const struct acpi_device_id mlxbf_i2c_acpi_ids[] = { + { "MLNXBF03", (kernel_ulong_t)&mlxbf_i2c_chip[MLXBF_I2C_CHIP_TYPE_1] }, + { "MLNXBF23", (kernel_ulong_t)&mlxbf_i2c_chip[MLXBF_I2C_CHIP_TYPE_2] }, + {}, +}; + +MODULE_DEVICE_TABLE(acpi, mlxbf_i2c_acpi_ids); + +static int mlxbf_i2c_acpi_probe(struct device *dev, struct mlxbf_i2c_priv *priv) +{ + const struct acpi_device_id *aid; + struct acpi_device *adev; + unsigned long bus_id = 0; + const char *uid; + int ret; + + if (acpi_disabled) + return -ENOENT; + + adev = ACPI_COMPANION(dev); + if (!adev) + return -ENXIO; + + aid = acpi_match_device(mlxbf_i2c_acpi_ids, dev); + if (!aid) + return -ENODEV; + + priv->chip = (struct mlxbf_i2c_chip_info *)aid->driver_data; + + uid = acpi_device_uid(adev); + if (!uid || !(*uid)) { + dev_err(dev, "Cannot retrieve UID\n"); + return -ENODEV; + } + + ret = kstrtoul(uid, 0, &bus_id); + if (!ret) + priv->bus = bus_id; + + return ret; +} +#else +static int mlxbf_i2c_acpi_probe(struct device *dev, struct mlxbf_i2c_priv *priv) +{ + return -ENOENT; +} +#endif /* CONFIG_ACPI */ + +static int mlxbf_i2c_of_probe(struct device *dev, struct mlxbf_i2c_priv *priv) +{ + const struct of_device_id *oid; + int bus_id = -1; + + if (IS_ENABLED(CONFIG_OF) && dev->of_node) { + oid = of_match_node(mlxbf_i2c_dt_ids, dev->of_node); + if (!oid) + return -ENODEV; + + priv->chip = oid->data; + + bus_id = of_alias_get_id(dev->of_node, "i2c"); + if (bus_id >= 0) + priv->bus = bus_id; + } + + if (bus_id < 0) { + dev_err(dev, "Cannot get bus id"); + return bus_id; + } + + return 0; +} + +static int mlxbf_i2c_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct mlxbf_i2c_priv *priv; + struct i2c_adapter *adap; + int irq, ret; + + priv = devm_kzalloc(dev, sizeof(struct mlxbf_i2c_priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + ret = mlxbf_i2c_acpi_probe(dev, priv); + if (ret < 0 && ret != -ENOENT && ret != -ENXIO) + ret = mlxbf_i2c_of_probe(dev, priv); + + if (ret < 0) + return ret; + + ret = mlxbf_i2c_init_resource(pdev, &priv->smbus, + MLXBF_I2C_SMBUS_RES); + if (ret < 0) { + dev_err(dev, "Cannot fetch smbus resource info"); + return ret; + } + + ret = mlxbf_i2c_init_resource(pdev, &priv->mst_cause, + MLXBF_I2C_MST_CAUSE_RES); + if (ret < 0) { + dev_err(dev, "Cannot fetch cause master resource info"); + return ret; + } + + ret = mlxbf_i2c_init_resource(pdev, &priv->slv_cause, + MLXBF_I2C_SLV_CAUSE_RES); + if (ret < 0) { + dev_err(dev, "Cannot fetch cause slave resource info"); + return ret; + } + + adap = &priv->adap; + adap->owner = THIS_MODULE; + adap->class = I2C_CLASS_HWMON; + adap->algo = &mlxbf_i2c_algo; + adap->quirks = &mlxbf_i2c_quirks; + adap->dev.parent = dev; + adap->dev.of_node = dev->of_node; + adap->nr = priv->bus; + + snprintf(adap->name, sizeof(adap->name), "i2c%d", adap->nr); + i2c_set_adapdata(adap, priv); + + /* Read Core PLL frequency. */ + ret = mlxbf_i2c_calculate_corepll_freq(pdev, priv); + if (ret < 0) { + dev_err(dev, "cannot get core clock frequency\n"); + /* Set to default value. */ + priv->frequency = MLXBF_I2C_COREPLL_FREQ; + } + + /* + * Initialize master. + * Note that a physical bus might be shared among Linux and firmware + * (e.g., ATF). Thus, the bus should be initialized and ready and + * bus initialization would be unnecessary. This requires additional + * knowledge about physical busses. But, since an extra initialization + * does not really hurt, then keep the code as is. + */ + ret = mlxbf_i2c_init_master(pdev, priv); + if (ret < 0) { + dev_err(dev, "failed to initialize smbus master %d", + priv->bus); + return ret; + } + + mlxbf_i2c_init_timings(pdev, priv); + + mlxbf_i2c_init_slave(pdev, priv); + + irq = platform_get_irq(pdev, 0); + if (irq < 0) + return irq; + ret = devm_request_irq(dev, irq, mlxbf_smbus_irq, + IRQF_ONESHOT | IRQF_SHARED | IRQF_PROBE_SHARED, + dev_name(dev), priv); + if (ret < 0) { + dev_err(dev, "Cannot get irq %d\n", irq); + return ret; + } + + priv->irq = irq; + + platform_set_drvdata(pdev, priv); + + ret = i2c_add_numbered_adapter(adap); + if (ret < 0) + return ret; + + mutex_lock(&mlxbf_i2c_bus_lock); + mlxbf_i2c_bus_count++; + mutex_unlock(&mlxbf_i2c_bus_lock); + + return 0; +} + +static int mlxbf_i2c_remove(struct platform_device *pdev) +{ + struct mlxbf_i2c_priv *priv = platform_get_drvdata(pdev); + struct device *dev = &pdev->dev; + struct resource *params; + + params = priv->smbus->params; + devm_release_mem_region(dev, params->start, resource_size(params)); + + params = priv->mst_cause->params; + devm_release_mem_region(dev, params->start, resource_size(params)); + + params = priv->slv_cause->params; + devm_release_mem_region(dev, params->start, resource_size(params)); + + /* + * Release shared resources. This should be done when releasing + * the I2C controller. + */ + mutex_lock(&mlxbf_i2c_bus_lock); + if (--mlxbf_i2c_bus_count == 0) { + mlxbf_i2c_release_coalesce(pdev, priv); + mlxbf_i2c_release_corepll(pdev, priv); + mlxbf_i2c_release_gpio(pdev, priv); + } + mutex_unlock(&mlxbf_i2c_bus_lock); + + devm_free_irq(dev, priv->irq, priv); + + i2c_del_adapter(&priv->adap); + + return 0; +} + +static struct platform_driver mlxbf_i2c_driver = { + .probe = mlxbf_i2c_probe, + .remove = mlxbf_i2c_remove, + .driver = { + .name = "i2c-mlxbf", + .of_match_table = mlxbf_i2c_dt_ids, +#ifdef CONFIG_ACPI + .acpi_match_table = ACPI_PTR(mlxbf_i2c_acpi_ids), +#endif /* CONFIG_ACPI */ + }, +}; + +static int __init mlxbf_i2c_init(void) +{ + mutex_init(&mlxbf_i2c_coalesce_lock); + mutex_init(&mlxbf_i2c_corepll_lock); + mutex_init(&mlxbf_i2c_gpio_lock); + + mutex_init(&mlxbf_i2c_bus_lock); + + return platform_driver_register(&mlxbf_i2c_driver); +} +module_init(mlxbf_i2c_init); + +static void __exit mlxbf_i2c_exit(void) +{ + platform_driver_unregister(&mlxbf_i2c_driver); + + mutex_destroy(&mlxbf_i2c_bus_lock); + + mutex_destroy(&mlxbf_i2c_gpio_lock); + mutex_destroy(&mlxbf_i2c_corepll_lock); + mutex_destroy(&mlxbf_i2c_coalesce_lock); +} +module_exit(mlxbf_i2c_exit); + +MODULE_DESCRIPTION("Mellanox BlueField I2C bus driver"); +MODULE_AUTHOR("Khalil Blaiech <kblaiech@nvidia.com>"); +MODULE_LICENSE("GPL v2"); |