diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/spi/spi-tegra20-sflash.c | 623 |
1 files changed, 623 insertions, 0 deletions
diff --git a/drivers/spi/spi-tegra20-sflash.c b/drivers/spi/spi-tegra20-sflash.c new file mode 100644 index 000000000..749288310 --- /dev/null +++ b/drivers/spi/spi-tegra20-sflash.c @@ -0,0 +1,623 @@ +/* + * SPI driver for Nvidia's Tegra20 Serial Flash Controller. + * + * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved. + * + * Author: Laxman Dewangan <ldewangan@nvidia.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/clk.h> +#include <linux/completion.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/kthread.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/pm_runtime.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/reset.h> +#include <linux/spi/spi.h> + +#define SPI_COMMAND 0x000 +#define SPI_GO BIT(30) +#define SPI_M_S BIT(28) +#define SPI_ACTIVE_SCLK_MASK (0x3 << 26) +#define SPI_ACTIVE_SCLK_DRIVE_LOW (0 << 26) +#define SPI_ACTIVE_SCLK_DRIVE_HIGH (1 << 26) +#define SPI_ACTIVE_SCLK_PULL_LOW (2 << 26) +#define SPI_ACTIVE_SCLK_PULL_HIGH (3 << 26) + +#define SPI_CK_SDA_FALLING (1 << 21) +#define SPI_CK_SDA_RISING (0 << 21) +#define SPI_CK_SDA_MASK (1 << 21) +#define SPI_ACTIVE_SDA (0x3 << 18) +#define SPI_ACTIVE_SDA_DRIVE_LOW (0 << 18) +#define SPI_ACTIVE_SDA_DRIVE_HIGH (1 << 18) +#define SPI_ACTIVE_SDA_PULL_LOW (2 << 18) +#define SPI_ACTIVE_SDA_PULL_HIGH (3 << 18) + +#define SPI_CS_POL_INVERT BIT(16) +#define SPI_TX_EN BIT(15) +#define SPI_RX_EN BIT(14) +#define SPI_CS_VAL_HIGH BIT(13) +#define SPI_CS_VAL_LOW 0x0 +#define SPI_CS_SW BIT(12) +#define SPI_CS_HW 0x0 +#define SPI_CS_DELAY_MASK (7 << 9) +#define SPI_CS3_EN BIT(8) +#define SPI_CS2_EN BIT(7) +#define SPI_CS1_EN BIT(6) +#define SPI_CS0_EN BIT(5) + +#define SPI_CS_MASK (SPI_CS3_EN | SPI_CS2_EN | \ + SPI_CS1_EN | SPI_CS0_EN) +#define SPI_BIT_LENGTH(x) (((x) & 0x1f) << 0) + +#define SPI_MODES (SPI_ACTIVE_SCLK_MASK | SPI_CK_SDA_MASK) + +#define SPI_STATUS 0x004 +#define SPI_BSY BIT(31) +#define SPI_RDY BIT(30) +#define SPI_TXF_FLUSH BIT(29) +#define SPI_RXF_FLUSH BIT(28) +#define SPI_RX_UNF BIT(27) +#define SPI_TX_OVF BIT(26) +#define SPI_RXF_EMPTY BIT(25) +#define SPI_RXF_FULL BIT(24) +#define SPI_TXF_EMPTY BIT(23) +#define SPI_TXF_FULL BIT(22) +#define SPI_BLK_CNT(count) (((count) & 0xffff) + 1) + +#define SPI_FIFO_ERROR (SPI_RX_UNF | SPI_TX_OVF) +#define SPI_FIFO_EMPTY (SPI_TX_EMPTY | SPI_RX_EMPTY) + +#define SPI_RX_CMP 0x8 +#define SPI_DMA_CTL 0x0C +#define SPI_DMA_EN BIT(31) +#define SPI_IE_RXC BIT(27) +#define SPI_IE_TXC BIT(26) +#define SPI_PACKED BIT(20) +#define SPI_RX_TRIG_MASK (0x3 << 18) +#define SPI_RX_TRIG_1W (0x0 << 18) +#define SPI_RX_TRIG_4W (0x1 << 18) +#define SPI_TX_TRIG_MASK (0x3 << 16) +#define SPI_TX_TRIG_1W (0x0 << 16) +#define SPI_TX_TRIG_4W (0x1 << 16) +#define SPI_DMA_BLK_COUNT(count) (((count) - 1) & 0xFFFF) + +#define SPI_TX_FIFO 0x10 +#define SPI_RX_FIFO 0x20 + +#define DATA_DIR_TX (1 << 0) +#define DATA_DIR_RX (1 << 1) + +#define MAX_CHIP_SELECT 4 +#define SPI_FIFO_DEPTH 4 +#define SPI_DMA_TIMEOUT (msecs_to_jiffies(1000)) + +struct tegra_sflash_data { + struct device *dev; + struct spi_master *master; + spinlock_t lock; + + struct clk *clk; + struct reset_control *rst; + void __iomem *base; + unsigned irq; + u32 cur_speed; + + struct spi_device *cur_spi; + unsigned cur_pos; + unsigned cur_len; + unsigned bytes_per_word; + unsigned cur_direction; + unsigned curr_xfer_words; + + unsigned cur_rx_pos; + unsigned cur_tx_pos; + + u32 tx_status; + u32 rx_status; + u32 status_reg; + + u32 def_command_reg; + u32 command_reg; + u32 dma_control_reg; + + struct completion xfer_completion; + struct spi_transfer *curr_xfer; +}; + +static int tegra_sflash_runtime_suspend(struct device *dev); +static int tegra_sflash_runtime_resume(struct device *dev); + +static inline u32 tegra_sflash_readl(struct tegra_sflash_data *tsd, + unsigned long reg) +{ + return readl(tsd->base + reg); +} + +static inline void tegra_sflash_writel(struct tegra_sflash_data *tsd, + u32 val, unsigned long reg) +{ + writel(val, tsd->base + reg); +} + +static void tegra_sflash_clear_status(struct tegra_sflash_data *tsd) +{ + /* Write 1 to clear status register */ + tegra_sflash_writel(tsd, SPI_RDY | SPI_FIFO_ERROR, SPI_STATUS); +} + +static unsigned tegra_sflash_calculate_curr_xfer_param( + struct spi_device *spi, struct tegra_sflash_data *tsd, + struct spi_transfer *t) +{ + unsigned remain_len = t->len - tsd->cur_pos; + unsigned max_word; + + tsd->bytes_per_word = DIV_ROUND_UP(t->bits_per_word, 8); + max_word = remain_len / tsd->bytes_per_word; + if (max_word > SPI_FIFO_DEPTH) + max_word = SPI_FIFO_DEPTH; + tsd->curr_xfer_words = max_word; + return max_word; +} + +static unsigned tegra_sflash_fill_tx_fifo_from_client_txbuf( + struct tegra_sflash_data *tsd, struct spi_transfer *t) +{ + unsigned nbytes; + u32 status; + unsigned max_n_32bit = tsd->curr_xfer_words; + u8 *tx_buf = (u8 *)t->tx_buf + tsd->cur_tx_pos; + + if (max_n_32bit > SPI_FIFO_DEPTH) + max_n_32bit = SPI_FIFO_DEPTH; + nbytes = max_n_32bit * tsd->bytes_per_word; + + status = tegra_sflash_readl(tsd, SPI_STATUS); + while (!(status & SPI_TXF_FULL)) { + int i; + u32 x = 0; + + for (i = 0; nbytes && (i < tsd->bytes_per_word); + i++, nbytes--) + x |= (u32)(*tx_buf++) << (i * 8); + tegra_sflash_writel(tsd, x, SPI_TX_FIFO); + if (!nbytes) + break; + + status = tegra_sflash_readl(tsd, SPI_STATUS); + } + tsd->cur_tx_pos += max_n_32bit * tsd->bytes_per_word; + return max_n_32bit; +} + +static int tegra_sflash_read_rx_fifo_to_client_rxbuf( + struct tegra_sflash_data *tsd, struct spi_transfer *t) +{ + u32 status; + unsigned int read_words = 0; + u8 *rx_buf = (u8 *)t->rx_buf + tsd->cur_rx_pos; + + status = tegra_sflash_readl(tsd, SPI_STATUS); + while (!(status & SPI_RXF_EMPTY)) { + int i; + u32 x = tegra_sflash_readl(tsd, SPI_RX_FIFO); + + for (i = 0; (i < tsd->bytes_per_word); i++) + *rx_buf++ = (x >> (i*8)) & 0xFF; + read_words++; + status = tegra_sflash_readl(tsd, SPI_STATUS); + } + tsd->cur_rx_pos += read_words * tsd->bytes_per_word; + return 0; +} + +static int tegra_sflash_start_cpu_based_transfer( + struct tegra_sflash_data *tsd, struct spi_transfer *t) +{ + u32 val = 0; + unsigned cur_words; + + if (tsd->cur_direction & DATA_DIR_TX) + val |= SPI_IE_TXC; + + if (tsd->cur_direction & DATA_DIR_RX) + val |= SPI_IE_RXC; + + tegra_sflash_writel(tsd, val, SPI_DMA_CTL); + tsd->dma_control_reg = val; + + if (tsd->cur_direction & DATA_DIR_TX) + cur_words = tegra_sflash_fill_tx_fifo_from_client_txbuf(tsd, t); + else + cur_words = tsd->curr_xfer_words; + val |= SPI_DMA_BLK_COUNT(cur_words); + tegra_sflash_writel(tsd, val, SPI_DMA_CTL); + tsd->dma_control_reg = val; + val |= SPI_DMA_EN; + tegra_sflash_writel(tsd, val, SPI_DMA_CTL); + return 0; +} + +static int tegra_sflash_start_transfer_one(struct spi_device *spi, + struct spi_transfer *t, bool is_first_of_msg, + bool is_single_xfer) +{ + struct tegra_sflash_data *tsd = spi_master_get_devdata(spi->master); + u32 speed; + u32 command; + + speed = t->speed_hz; + if (speed != tsd->cur_speed) { + clk_set_rate(tsd->clk, speed); + tsd->cur_speed = speed; + } + + tsd->cur_spi = spi; + tsd->cur_pos = 0; + tsd->cur_rx_pos = 0; + tsd->cur_tx_pos = 0; + tsd->curr_xfer = t; + tegra_sflash_calculate_curr_xfer_param(spi, tsd, t); + if (is_first_of_msg) { + command = tsd->def_command_reg; + command |= SPI_BIT_LENGTH(t->bits_per_word - 1); + command |= SPI_CS_VAL_HIGH; + + command &= ~SPI_MODES; + if (spi->mode & SPI_CPHA) + command |= SPI_CK_SDA_FALLING; + + if (spi->mode & SPI_CPOL) + command |= SPI_ACTIVE_SCLK_DRIVE_HIGH; + else + command |= SPI_ACTIVE_SCLK_DRIVE_LOW; + command |= SPI_CS0_EN << spi->chip_select; + } else { + command = tsd->command_reg; + command &= ~SPI_BIT_LENGTH(~0); + command |= SPI_BIT_LENGTH(t->bits_per_word - 1); + command &= ~(SPI_RX_EN | SPI_TX_EN); + } + + tsd->cur_direction = 0; + if (t->rx_buf) { + command |= SPI_RX_EN; + tsd->cur_direction |= DATA_DIR_RX; + } + if (t->tx_buf) { + command |= SPI_TX_EN; + tsd->cur_direction |= DATA_DIR_TX; + } + tegra_sflash_writel(tsd, command, SPI_COMMAND); + tsd->command_reg = command; + + return tegra_sflash_start_cpu_based_transfer(tsd, t); +} + +static int tegra_sflash_transfer_one_message(struct spi_master *master, + struct spi_message *msg) +{ + bool is_first_msg = true; + int single_xfer; + struct tegra_sflash_data *tsd = spi_master_get_devdata(master); + struct spi_transfer *xfer; + struct spi_device *spi = msg->spi; + int ret; + + msg->status = 0; + msg->actual_length = 0; + single_xfer = list_is_singular(&msg->transfers); + list_for_each_entry(xfer, &msg->transfers, transfer_list) { + reinit_completion(&tsd->xfer_completion); + ret = tegra_sflash_start_transfer_one(spi, xfer, + is_first_msg, single_xfer); + if (ret < 0) { + dev_err(tsd->dev, + "spi can not start transfer, err %d\n", ret); + goto exit; + } + is_first_msg = false; + ret = wait_for_completion_timeout(&tsd->xfer_completion, + SPI_DMA_TIMEOUT); + if (WARN_ON(ret == 0)) { + dev_err(tsd->dev, + "spi transfer timeout, err %d\n", ret); + ret = -EIO; + goto exit; + } + + if (tsd->tx_status || tsd->rx_status) { + dev_err(tsd->dev, "Error in Transfer\n"); + ret = -EIO; + goto exit; + } + msg->actual_length += xfer->len; + if (xfer->cs_change && xfer->delay_usecs) { + tegra_sflash_writel(tsd, tsd->def_command_reg, + SPI_COMMAND); + udelay(xfer->delay_usecs); + } + } + ret = 0; +exit: + tegra_sflash_writel(tsd, tsd->def_command_reg, SPI_COMMAND); + msg->status = ret; + spi_finalize_current_message(master); + return ret; +} + +static irqreturn_t handle_cpu_based_xfer(struct tegra_sflash_data *tsd) +{ + struct spi_transfer *t = tsd->curr_xfer; + unsigned long flags; + + spin_lock_irqsave(&tsd->lock, flags); + if (tsd->tx_status || tsd->rx_status || (tsd->status_reg & SPI_BSY)) { + dev_err(tsd->dev, + "CpuXfer ERROR bit set 0x%x\n", tsd->status_reg); + dev_err(tsd->dev, + "CpuXfer 0x%08x:0x%08x\n", tsd->command_reg, + tsd->dma_control_reg); + reset_control_assert(tsd->rst); + udelay(2); + reset_control_deassert(tsd->rst); + complete(&tsd->xfer_completion); + goto exit; + } + + if (tsd->cur_direction & DATA_DIR_RX) + tegra_sflash_read_rx_fifo_to_client_rxbuf(tsd, t); + + if (tsd->cur_direction & DATA_DIR_TX) + tsd->cur_pos = tsd->cur_tx_pos; + else + tsd->cur_pos = tsd->cur_rx_pos; + + if (tsd->cur_pos == t->len) { + complete(&tsd->xfer_completion); + goto exit; + } + + tegra_sflash_calculate_curr_xfer_param(tsd->cur_spi, tsd, t); + tegra_sflash_start_cpu_based_transfer(tsd, t); +exit: + spin_unlock_irqrestore(&tsd->lock, flags); + return IRQ_HANDLED; +} + +static irqreturn_t tegra_sflash_isr(int irq, void *context_data) +{ + struct tegra_sflash_data *tsd = context_data; + + tsd->status_reg = tegra_sflash_readl(tsd, SPI_STATUS); + if (tsd->cur_direction & DATA_DIR_TX) + tsd->tx_status = tsd->status_reg & SPI_TX_OVF; + + if (tsd->cur_direction & DATA_DIR_RX) + tsd->rx_status = tsd->status_reg & SPI_RX_UNF; + tegra_sflash_clear_status(tsd); + + return handle_cpu_based_xfer(tsd); +} + +static const struct of_device_id tegra_sflash_of_match[] = { + { .compatible = "nvidia,tegra20-sflash", }, + {} +}; +MODULE_DEVICE_TABLE(of, tegra_sflash_of_match); + +static int tegra_sflash_probe(struct platform_device *pdev) +{ + struct spi_master *master; + struct tegra_sflash_data *tsd; + struct resource *r; + int ret; + const struct of_device_id *match; + + match = of_match_device(tegra_sflash_of_match, &pdev->dev); + if (!match) { + dev_err(&pdev->dev, "Error: No device match found\n"); + return -ENODEV; + } + + master = spi_alloc_master(&pdev->dev, sizeof(*tsd)); + if (!master) { + dev_err(&pdev->dev, "master allocation failed\n"); + return -ENOMEM; + } + + /* the spi->mode bits understood by this driver: */ + master->mode_bits = SPI_CPOL | SPI_CPHA; + master->transfer_one_message = tegra_sflash_transfer_one_message; + master->auto_runtime_pm = true; + master->num_chipselect = MAX_CHIP_SELECT; + + platform_set_drvdata(pdev, master); + tsd = spi_master_get_devdata(master); + tsd->master = master; + tsd->dev = &pdev->dev; + spin_lock_init(&tsd->lock); + + if (of_property_read_u32(tsd->dev->of_node, "spi-max-frequency", + &master->max_speed_hz)) + master->max_speed_hz = 25000000; /* 25MHz */ + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + tsd->base = devm_ioremap_resource(&pdev->dev, r); + if (IS_ERR(tsd->base)) { + ret = PTR_ERR(tsd->base); + goto exit_free_master; + } + + tsd->irq = platform_get_irq(pdev, 0); + ret = request_irq(tsd->irq, tegra_sflash_isr, 0, + dev_name(&pdev->dev), tsd); + if (ret < 0) { + dev_err(&pdev->dev, "Failed to register ISR for IRQ %d\n", + tsd->irq); + goto exit_free_master; + } + + tsd->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(tsd->clk)) { + dev_err(&pdev->dev, "can not get clock\n"); + ret = PTR_ERR(tsd->clk); + goto exit_free_irq; + } + + tsd->rst = devm_reset_control_get_exclusive(&pdev->dev, "spi"); + if (IS_ERR(tsd->rst)) { + dev_err(&pdev->dev, "can not get reset\n"); + ret = PTR_ERR(tsd->rst); + goto exit_free_irq; + } + + init_completion(&tsd->xfer_completion); + pm_runtime_enable(&pdev->dev); + if (!pm_runtime_enabled(&pdev->dev)) { + ret = tegra_sflash_runtime_resume(&pdev->dev); + if (ret) + goto exit_pm_disable; + } + + ret = pm_runtime_get_sync(&pdev->dev); + if (ret < 0) { + dev_err(&pdev->dev, "pm runtime get failed, e = %d\n", ret); + goto exit_pm_disable; + } + + /* Reset controller */ + reset_control_assert(tsd->rst); + udelay(2); + reset_control_deassert(tsd->rst); + + tsd->def_command_reg = SPI_M_S | SPI_CS_SW; + tegra_sflash_writel(tsd, tsd->def_command_reg, SPI_COMMAND); + pm_runtime_put(&pdev->dev); + + master->dev.of_node = pdev->dev.of_node; + ret = devm_spi_register_master(&pdev->dev, master); + if (ret < 0) { + dev_err(&pdev->dev, "can not register to master err %d\n", ret); + goto exit_pm_disable; + } + return ret; + +exit_pm_disable: + pm_runtime_disable(&pdev->dev); + if (!pm_runtime_status_suspended(&pdev->dev)) + tegra_sflash_runtime_suspend(&pdev->dev); +exit_free_irq: + free_irq(tsd->irq, tsd); +exit_free_master: + spi_master_put(master); + return ret; +} + +static int tegra_sflash_remove(struct platform_device *pdev) +{ + struct spi_master *master = platform_get_drvdata(pdev); + struct tegra_sflash_data *tsd = spi_master_get_devdata(master); + + free_irq(tsd->irq, tsd); + + pm_runtime_disable(&pdev->dev); + if (!pm_runtime_status_suspended(&pdev->dev)) + tegra_sflash_runtime_suspend(&pdev->dev); + + return 0; +} + +#ifdef CONFIG_PM_SLEEP +static int tegra_sflash_suspend(struct device *dev) +{ + struct spi_master *master = dev_get_drvdata(dev); + + return spi_master_suspend(master); +} + +static int tegra_sflash_resume(struct device *dev) +{ + struct spi_master *master = dev_get_drvdata(dev); + struct tegra_sflash_data *tsd = spi_master_get_devdata(master); + int ret; + + ret = pm_runtime_get_sync(dev); + if (ret < 0) { + pm_runtime_put_noidle(dev); + dev_err(dev, "pm runtime failed, e = %d\n", ret); + return ret; + } + tegra_sflash_writel(tsd, tsd->command_reg, SPI_COMMAND); + pm_runtime_put(dev); + + return spi_master_resume(master); +} +#endif + +static int tegra_sflash_runtime_suspend(struct device *dev) +{ + struct spi_master *master = dev_get_drvdata(dev); + struct tegra_sflash_data *tsd = spi_master_get_devdata(master); + + /* Flush all write which are in PPSB queue by reading back */ + tegra_sflash_readl(tsd, SPI_COMMAND); + + clk_disable_unprepare(tsd->clk); + return 0; +} + +static int tegra_sflash_runtime_resume(struct device *dev) +{ + struct spi_master *master = dev_get_drvdata(dev); + struct tegra_sflash_data *tsd = spi_master_get_devdata(master); + int ret; + + ret = clk_prepare_enable(tsd->clk); + if (ret < 0) { + dev_err(tsd->dev, "clk_prepare failed: %d\n", ret); + return ret; + } + return 0; +} + +static const struct dev_pm_ops slink_pm_ops = { + SET_RUNTIME_PM_OPS(tegra_sflash_runtime_suspend, + tegra_sflash_runtime_resume, NULL) + SET_SYSTEM_SLEEP_PM_OPS(tegra_sflash_suspend, tegra_sflash_resume) +}; +static struct platform_driver tegra_sflash_driver = { + .driver = { + .name = "spi-tegra-sflash", + .pm = &slink_pm_ops, + .of_match_table = tegra_sflash_of_match, + }, + .probe = tegra_sflash_probe, + .remove = tegra_sflash_remove, +}; +module_platform_driver(tegra_sflash_driver); + +MODULE_ALIAS("platform:spi-tegra-sflash"); +MODULE_DESCRIPTION("NVIDIA Tegra20 Serial Flash Controller Driver"); +MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>"); +MODULE_LICENSE("GPL v2"); |