diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/memory/tegra/tegra20-emc.c | 1292 |
1 files changed, 1292 insertions, 0 deletions
diff --git a/drivers/memory/tegra/tegra20-emc.c b/drivers/memory/tegra/tegra20-emc.c new file mode 100644 index 000000000..d1f01f80d --- /dev/null +++ b/drivers/memory/tegra/tegra20-emc.c @@ -0,0 +1,1292 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Tegra20 External Memory Controller driver + * + * Author: Dmitry Osipenko <digetx@gmail.com> + */ + +#include <linux/bitfield.h> +#include <linux/clk.h> +#include <linux/clk/tegra.h> +#include <linux/debugfs.h> +#include <linux/devfreq.h> +#include <linux/err.h> +#include <linux/interconnect-provider.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/iopoll.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/pm_opp.h> +#include <linux/slab.h> +#include <linux/sort.h> +#include <linux/types.h> + +#include <soc/tegra/common.h> +#include <soc/tegra/fuse.h> + +#include "../jedec_ddr.h" +#include "../of_memory.h" + +#include "mc.h" + +#define EMC_INTSTATUS 0x000 +#define EMC_INTMASK 0x004 +#define EMC_DBG 0x008 +#define EMC_ADR_CFG_0 0x010 +#define EMC_TIMING_CONTROL 0x028 +#define EMC_RC 0x02c +#define EMC_RFC 0x030 +#define EMC_RAS 0x034 +#define EMC_RP 0x038 +#define EMC_R2W 0x03c +#define EMC_W2R 0x040 +#define EMC_R2P 0x044 +#define EMC_W2P 0x048 +#define EMC_RD_RCD 0x04c +#define EMC_WR_RCD 0x050 +#define EMC_RRD 0x054 +#define EMC_REXT 0x058 +#define EMC_WDV 0x05c +#define EMC_QUSE 0x060 +#define EMC_QRST 0x064 +#define EMC_QSAFE 0x068 +#define EMC_RDV 0x06c +#define EMC_REFRESH 0x070 +#define EMC_BURST_REFRESH_NUM 0x074 +#define EMC_PDEX2WR 0x078 +#define EMC_PDEX2RD 0x07c +#define EMC_PCHG2PDEN 0x080 +#define EMC_ACT2PDEN 0x084 +#define EMC_AR2PDEN 0x088 +#define EMC_RW2PDEN 0x08c +#define EMC_TXSR 0x090 +#define EMC_TCKE 0x094 +#define EMC_TFAW 0x098 +#define EMC_TRPAB 0x09c +#define EMC_TCLKSTABLE 0x0a0 +#define EMC_TCLKSTOP 0x0a4 +#define EMC_TREFBW 0x0a8 +#define EMC_QUSE_EXTRA 0x0ac +#define EMC_ODT_WRITE 0x0b0 +#define EMC_ODT_READ 0x0b4 +#define EMC_MRR 0x0ec +#define EMC_FBIO_CFG5 0x104 +#define EMC_FBIO_CFG6 0x114 +#define EMC_STAT_CONTROL 0x160 +#define EMC_STAT_LLMC_CONTROL 0x178 +#define EMC_STAT_PWR_CLOCK_LIMIT 0x198 +#define EMC_STAT_PWR_CLOCKS 0x19c +#define EMC_STAT_PWR_COUNT 0x1a0 +#define EMC_AUTO_CAL_INTERVAL 0x2a8 +#define EMC_CFG_2 0x2b8 +#define EMC_CFG_DIG_DLL 0x2bc +#define EMC_DLL_XFORM_DQS 0x2c0 +#define EMC_DLL_XFORM_QUSE 0x2c4 +#define EMC_ZCAL_REF_CNT 0x2e0 +#define EMC_ZCAL_WAIT_CNT 0x2e4 +#define EMC_CFG_CLKTRIM_0 0x2d0 +#define EMC_CFG_CLKTRIM_1 0x2d4 +#define EMC_CFG_CLKTRIM_2 0x2d8 + +#define EMC_CLKCHANGE_REQ_ENABLE BIT(0) +#define EMC_CLKCHANGE_PD_ENABLE BIT(1) +#define EMC_CLKCHANGE_SR_ENABLE BIT(2) + +#define EMC_TIMING_UPDATE BIT(0) + +#define EMC_REFRESH_OVERFLOW_INT BIT(3) +#define EMC_CLKCHANGE_COMPLETE_INT BIT(4) +#define EMC_MRR_DIVLD_INT BIT(5) + +#define EMC_DBG_READ_MUX_ASSEMBLY BIT(0) +#define EMC_DBG_WRITE_MUX_ACTIVE BIT(1) +#define EMC_DBG_FORCE_UPDATE BIT(2) +#define EMC_DBG_READ_DQM_CTRL BIT(9) +#define EMC_DBG_CFG_PRIORITY BIT(24) + +#define EMC_FBIO_CFG5_DRAM_WIDTH_X16 BIT(4) +#define EMC_FBIO_CFG5_DRAM_TYPE GENMASK(1, 0) + +#define EMC_MRR_DEV_SELECTN GENMASK(31, 30) +#define EMC_MRR_MRR_MA GENMASK(23, 16) +#define EMC_MRR_MRR_DATA GENMASK(15, 0) + +#define EMC_ADR_CFG_0_EMEM_NUMDEV GENMASK(25, 24) + +#define EMC_PWR_GATHER_CLEAR (1 << 8) +#define EMC_PWR_GATHER_DISABLE (2 << 8) +#define EMC_PWR_GATHER_ENABLE (3 << 8) + +enum emc_dram_type { + DRAM_TYPE_RESERVED, + DRAM_TYPE_DDR1, + DRAM_TYPE_LPDDR2, + DRAM_TYPE_DDR2, +}; + +static const u16 emc_timing_registers[] = { + EMC_RC, + EMC_RFC, + EMC_RAS, + EMC_RP, + EMC_R2W, + EMC_W2R, + EMC_R2P, + EMC_W2P, + EMC_RD_RCD, + EMC_WR_RCD, + EMC_RRD, + EMC_REXT, + EMC_WDV, + EMC_QUSE, + EMC_QRST, + EMC_QSAFE, + EMC_RDV, + EMC_REFRESH, + EMC_BURST_REFRESH_NUM, + EMC_PDEX2WR, + EMC_PDEX2RD, + EMC_PCHG2PDEN, + EMC_ACT2PDEN, + EMC_AR2PDEN, + EMC_RW2PDEN, + EMC_TXSR, + EMC_TCKE, + EMC_TFAW, + EMC_TRPAB, + EMC_TCLKSTABLE, + EMC_TCLKSTOP, + EMC_TREFBW, + EMC_QUSE_EXTRA, + EMC_FBIO_CFG6, + EMC_ODT_WRITE, + EMC_ODT_READ, + EMC_FBIO_CFG5, + EMC_CFG_DIG_DLL, + EMC_DLL_XFORM_DQS, + EMC_DLL_XFORM_QUSE, + EMC_ZCAL_REF_CNT, + EMC_ZCAL_WAIT_CNT, + EMC_AUTO_CAL_INTERVAL, + EMC_CFG_CLKTRIM_0, + EMC_CFG_CLKTRIM_1, + EMC_CFG_CLKTRIM_2, +}; + +struct emc_timing { + unsigned long rate; + u32 data[ARRAY_SIZE(emc_timing_registers)]; +}; + +enum emc_rate_request_type { + EMC_RATE_DEVFREQ, + EMC_RATE_DEBUG, + EMC_RATE_ICC, + EMC_RATE_TYPE_MAX, +}; + +struct emc_rate_request { + unsigned long min_rate; + unsigned long max_rate; +}; + +struct tegra_emc { + struct device *dev; + struct tegra_mc *mc; + struct icc_provider provider; + struct notifier_block clk_nb; + struct clk *clk; + void __iomem *regs; + unsigned int dram_bus_width; + + struct emc_timing *timings; + unsigned int num_timings; + + struct { + struct dentry *root; + unsigned long min_rate; + unsigned long max_rate; + } debugfs; + + /* + * There are multiple sources in the EMC driver which could request + * a min/max clock rate, these rates are contained in this array. + */ + struct emc_rate_request requested_rate[EMC_RATE_TYPE_MAX]; + + /* protect shared rate-change code path */ + struct mutex rate_lock; + + struct devfreq_simple_ondemand_data ondemand_data; + + /* memory chip identity information */ + union lpddr2_basic_config4 basic_conf4; + unsigned int manufacturer_id; + unsigned int revision_id1; + unsigned int revision_id2; + + bool mrr_error; +}; + +static irqreturn_t tegra_emc_isr(int irq, void *data) +{ + struct tegra_emc *emc = data; + u32 intmask = EMC_REFRESH_OVERFLOW_INT; + u32 status; + + status = readl_relaxed(emc->regs + EMC_INTSTATUS) & intmask; + if (!status) + return IRQ_NONE; + + /* notify about HW problem */ + if (status & EMC_REFRESH_OVERFLOW_INT) + dev_err_ratelimited(emc->dev, + "refresh request overflow timeout\n"); + + /* clear interrupts */ + writel_relaxed(status, emc->regs + EMC_INTSTATUS); + + return IRQ_HANDLED; +} + +static struct emc_timing *tegra_emc_find_timing(struct tegra_emc *emc, + unsigned long rate) +{ + struct emc_timing *timing = NULL; + unsigned int i; + + for (i = 0; i < emc->num_timings; i++) { + if (emc->timings[i].rate >= rate) { + timing = &emc->timings[i]; + break; + } + } + + if (!timing) { + dev_err(emc->dev, "no timing for rate %lu\n", rate); + return NULL; + } + + return timing; +} + +static int emc_prepare_timing_change(struct tegra_emc *emc, unsigned long rate) +{ + struct emc_timing *timing = tegra_emc_find_timing(emc, rate); + unsigned int i; + + if (!timing) + return -EINVAL; + + dev_dbg(emc->dev, "%s: using timing rate %lu for requested rate %lu\n", + __func__, timing->rate, rate); + + /* program shadow registers */ + for (i = 0; i < ARRAY_SIZE(timing->data); i++) + writel_relaxed(timing->data[i], + emc->regs + emc_timing_registers[i]); + + /* wait until programming has settled */ + readl_relaxed(emc->regs + emc_timing_registers[i - 1]); + + return 0; +} + +static int emc_complete_timing_change(struct tegra_emc *emc, bool flush) +{ + int err; + u32 v; + + dev_dbg(emc->dev, "%s: flush %d\n", __func__, flush); + + if (flush) { + /* manually initiate memory timing update */ + writel_relaxed(EMC_TIMING_UPDATE, + emc->regs + EMC_TIMING_CONTROL); + return 0; + } + + err = readl_relaxed_poll_timeout_atomic(emc->regs + EMC_INTSTATUS, v, + v & EMC_CLKCHANGE_COMPLETE_INT, + 1, 100); + if (err) { + dev_err(emc->dev, "emc-car handshake timeout: %d\n", err); + return err; + } + + return 0; +} + +static int tegra_emc_clk_change_notify(struct notifier_block *nb, + unsigned long msg, void *data) +{ + struct tegra_emc *emc = container_of(nb, struct tegra_emc, clk_nb); + struct clk_notifier_data *cnd = data; + int err; + + switch (msg) { + case PRE_RATE_CHANGE: + err = emc_prepare_timing_change(emc, cnd->new_rate); + break; + + case ABORT_RATE_CHANGE: + err = emc_prepare_timing_change(emc, cnd->old_rate); + if (err) + break; + + err = emc_complete_timing_change(emc, true); + break; + + case POST_RATE_CHANGE: + err = emc_complete_timing_change(emc, false); + break; + + default: + return NOTIFY_DONE; + } + + return notifier_from_errno(err); +} + +static int load_one_timing_from_dt(struct tegra_emc *emc, + struct emc_timing *timing, + struct device_node *node) +{ + u32 rate; + int err; + + if (!of_device_is_compatible(node, "nvidia,tegra20-emc-table")) { + dev_err(emc->dev, "incompatible DT node: %pOF\n", node); + return -EINVAL; + } + + err = of_property_read_u32(node, "clock-frequency", &rate); + if (err) { + dev_err(emc->dev, "timing %pOF: failed to read rate: %d\n", + node, err); + return err; + } + + err = of_property_read_u32_array(node, "nvidia,emc-registers", + timing->data, + ARRAY_SIZE(emc_timing_registers)); + if (err) { + dev_err(emc->dev, + "timing %pOF: failed to read emc timing data: %d\n", + node, err); + return err; + } + + /* + * The EMC clock rate is twice the bus rate, and the bus rate is + * measured in kHz. + */ + timing->rate = rate * 2 * 1000; + + dev_dbg(emc->dev, "%s: %pOF: EMC rate %lu\n", + __func__, node, timing->rate); + + return 0; +} + +static int cmp_timings(const void *_a, const void *_b) +{ + const struct emc_timing *a = _a; + const struct emc_timing *b = _b; + + if (a->rate < b->rate) + return -1; + + if (a->rate > b->rate) + return 1; + + return 0; +} + +static int tegra_emc_load_timings_from_dt(struct tegra_emc *emc, + struct device_node *node) +{ + struct device_node *child; + struct emc_timing *timing; + int child_count; + int err; + + child_count = of_get_child_count(node); + if (!child_count) { + dev_err(emc->dev, "no memory timings in DT node: %pOF\n", node); + return -EINVAL; + } + + emc->timings = devm_kcalloc(emc->dev, child_count, sizeof(*timing), + GFP_KERNEL); + if (!emc->timings) + return -ENOMEM; + + timing = emc->timings; + + for_each_child_of_node(node, child) { + if (of_node_name_eq(child, "lpddr2")) + continue; + + err = load_one_timing_from_dt(emc, timing++, child); + if (err) { + of_node_put(child); + return err; + } + + emc->num_timings++; + } + + sort(emc->timings, emc->num_timings, sizeof(*timing), cmp_timings, + NULL); + + dev_info_once(emc->dev, + "got %u timings for RAM code %u (min %luMHz max %luMHz)\n", + emc->num_timings, + tegra_read_ram_code(), + emc->timings[0].rate / 1000000, + emc->timings[emc->num_timings - 1].rate / 1000000); + + return 0; +} + +static struct device_node * +tegra_emc_find_node_by_ram_code(struct tegra_emc *emc) +{ + struct device *dev = emc->dev; + struct device_node *np; + u32 value, ram_code; + int err; + + if (emc->mrr_error) { + dev_warn(dev, "memory timings skipped due to MRR error\n"); + return NULL; + } + + if (of_get_child_count(dev->of_node) == 0) { + dev_info_once(dev, "device-tree doesn't have memory timings\n"); + return NULL; + } + + if (!of_property_read_bool(dev->of_node, "nvidia,use-ram-code")) + return of_node_get(dev->of_node); + + ram_code = tegra_read_ram_code(); + + for (np = of_find_node_by_name(dev->of_node, "emc-tables"); np; + np = of_find_node_by_name(np, "emc-tables")) { + err = of_property_read_u32(np, "nvidia,ram-code", &value); + if (err || value != ram_code) { + struct device_node *lpddr2_np; + bool cfg_mismatches = false; + + lpddr2_np = of_find_node_by_name(np, "lpddr2"); + if (lpddr2_np) { + const struct lpddr2_info *info; + + info = of_lpddr2_get_info(lpddr2_np, dev); + if (info) { + if (info->manufacturer_id >= 0 && + info->manufacturer_id != emc->manufacturer_id) + cfg_mismatches = true; + + if (info->revision_id1 >= 0 && + info->revision_id1 != emc->revision_id1) + cfg_mismatches = true; + + if (info->revision_id2 >= 0 && + info->revision_id2 != emc->revision_id2) + cfg_mismatches = true; + + if (info->density != emc->basic_conf4.density) + cfg_mismatches = true; + + if (info->io_width != emc->basic_conf4.io_width) + cfg_mismatches = true; + + if (info->arch_type != emc->basic_conf4.arch_type) + cfg_mismatches = true; + } else { + dev_err(dev, "failed to parse %pOF\n", lpddr2_np); + cfg_mismatches = true; + } + + of_node_put(lpddr2_np); + } else { + cfg_mismatches = true; + } + + if (cfg_mismatches) { + of_node_put(np); + continue; + } + } + + return np; + } + + dev_err(dev, "no memory timings for RAM code %u found in device tree\n", + ram_code); + + return NULL; +} + +static int emc_read_lpddr_mode_register(struct tegra_emc *emc, + unsigned int emem_dev, + unsigned int register_addr, + unsigned int *register_data) +{ + u32 memory_dev = emem_dev ? 1 : 2; + u32 val, mr_mask = 0xff; + int err; + + /* clear data-valid interrupt status */ + writel_relaxed(EMC_MRR_DIVLD_INT, emc->regs + EMC_INTSTATUS); + + /* issue mode register read request */ + val = FIELD_PREP(EMC_MRR_DEV_SELECTN, memory_dev); + val |= FIELD_PREP(EMC_MRR_MRR_MA, register_addr); + + writel_relaxed(val, emc->regs + EMC_MRR); + + /* wait for the LPDDR2 data-valid interrupt */ + err = readl_relaxed_poll_timeout_atomic(emc->regs + EMC_INTSTATUS, val, + val & EMC_MRR_DIVLD_INT, + 1, 100); + if (err) { + dev_err(emc->dev, "mode register %u read failed: %d\n", + register_addr, err); + emc->mrr_error = true; + return err; + } + + /* read out mode register data */ + val = readl_relaxed(emc->regs + EMC_MRR); + *register_data = FIELD_GET(EMC_MRR_MRR_DATA, val) & mr_mask; + + return 0; +} + +static void emc_read_lpddr_sdram_info(struct tegra_emc *emc, + unsigned int emem_dev, + bool print_out) +{ + /* these registers are standard for all LPDDR JEDEC memory chips */ + emc_read_lpddr_mode_register(emc, emem_dev, 5, &emc->manufacturer_id); + emc_read_lpddr_mode_register(emc, emem_dev, 6, &emc->revision_id1); + emc_read_lpddr_mode_register(emc, emem_dev, 7, &emc->revision_id2); + emc_read_lpddr_mode_register(emc, emem_dev, 8, &emc->basic_conf4.value); + + if (!print_out) + return; + + dev_info(emc->dev, "SDRAM[dev%u]: manufacturer: 0x%x (%s) rev1: 0x%x rev2: 0x%x prefetch: S%u density: %uMbit iowidth: %ubit\n", + emem_dev, emc->manufacturer_id, + lpddr2_jedec_manufacturer(emc->manufacturer_id), + emc->revision_id1, emc->revision_id2, + 4 >> emc->basic_conf4.arch_type, + 64 << emc->basic_conf4.density, + 32 >> emc->basic_conf4.io_width); +} + +static int emc_setup_hw(struct tegra_emc *emc) +{ + u32 emc_cfg, emc_dbg, emc_fbio, emc_adr_cfg; + u32 intmask = EMC_REFRESH_OVERFLOW_INT; + static bool print_sdram_info_once; + enum emc_dram_type dram_type; + const char *dram_type_str; + unsigned int emem_numdev; + + emc_cfg = readl_relaxed(emc->regs + EMC_CFG_2); + + /* + * Depending on a memory type, DRAM should enter either self-refresh + * or power-down state on EMC clock change. + */ + if (!(emc_cfg & EMC_CLKCHANGE_PD_ENABLE) && + !(emc_cfg & EMC_CLKCHANGE_SR_ENABLE)) { + dev_err(emc->dev, + "bootloader didn't specify DRAM auto-suspend mode\n"); + return -EINVAL; + } + + /* enable EMC and CAR to handshake on PLL divider/source changes */ + emc_cfg |= EMC_CLKCHANGE_REQ_ENABLE; + writel_relaxed(emc_cfg, emc->regs + EMC_CFG_2); + + /* initialize interrupt */ + writel_relaxed(intmask, emc->regs + EMC_INTMASK); + writel_relaxed(intmask, emc->regs + EMC_INTSTATUS); + + /* ensure that unwanted debug features are disabled */ + emc_dbg = readl_relaxed(emc->regs + EMC_DBG); + emc_dbg |= EMC_DBG_CFG_PRIORITY; + emc_dbg &= ~EMC_DBG_READ_MUX_ASSEMBLY; + emc_dbg &= ~EMC_DBG_WRITE_MUX_ACTIVE; + emc_dbg &= ~EMC_DBG_FORCE_UPDATE; + writel_relaxed(emc_dbg, emc->regs + EMC_DBG); + + emc_fbio = readl_relaxed(emc->regs + EMC_FBIO_CFG5); + + if (emc_fbio & EMC_FBIO_CFG5_DRAM_WIDTH_X16) + emc->dram_bus_width = 16; + else + emc->dram_bus_width = 32; + + dram_type = FIELD_GET(EMC_FBIO_CFG5_DRAM_TYPE, emc_fbio); + + switch (dram_type) { + case DRAM_TYPE_RESERVED: + dram_type_str = "INVALID"; + break; + case DRAM_TYPE_DDR1: + dram_type_str = "DDR1"; + break; + case DRAM_TYPE_LPDDR2: + dram_type_str = "LPDDR2"; + break; + case DRAM_TYPE_DDR2: + dram_type_str = "DDR2"; + break; + } + + emc_adr_cfg = readl_relaxed(emc->regs + EMC_ADR_CFG_0); + emem_numdev = FIELD_GET(EMC_ADR_CFG_0_EMEM_NUMDEV, emc_adr_cfg) + 1; + + dev_info_once(emc->dev, "%ubit DRAM bus, %u %s %s attached\n", + emc->dram_bus_width, emem_numdev, dram_type_str, + emem_numdev == 2 ? "devices" : "device"); + + if (dram_type == DRAM_TYPE_LPDDR2) { + while (emem_numdev--) + emc_read_lpddr_sdram_info(emc, emem_numdev, + !print_sdram_info_once); + print_sdram_info_once = true; + } + + return 0; +} + +static long emc_round_rate(unsigned long rate, + unsigned long min_rate, + unsigned long max_rate, + void *arg) +{ + struct emc_timing *timing = NULL; + struct tegra_emc *emc = arg; + unsigned int i; + + if (!emc->num_timings) + return clk_get_rate(emc->clk); + + min_rate = min(min_rate, emc->timings[emc->num_timings - 1].rate); + + for (i = 0; i < emc->num_timings; i++) { + if (emc->timings[i].rate < rate && i != emc->num_timings - 1) + continue; + + if (emc->timings[i].rate > max_rate) { + i = max(i, 1u) - 1; + + if (emc->timings[i].rate < min_rate) + break; + } + + if (emc->timings[i].rate < min_rate) + continue; + + timing = &emc->timings[i]; + break; + } + + if (!timing) { + dev_err(emc->dev, "no timing for rate %lu min %lu max %lu\n", + rate, min_rate, max_rate); + return -EINVAL; + } + + return timing->rate; +} + +static void tegra_emc_rate_requests_init(struct tegra_emc *emc) +{ + unsigned int i; + + for (i = 0; i < EMC_RATE_TYPE_MAX; i++) { + emc->requested_rate[i].min_rate = 0; + emc->requested_rate[i].max_rate = ULONG_MAX; + } +} + +static int emc_request_rate(struct tegra_emc *emc, + unsigned long new_min_rate, + unsigned long new_max_rate, + enum emc_rate_request_type type) +{ + struct emc_rate_request *req = emc->requested_rate; + unsigned long min_rate = 0, max_rate = ULONG_MAX; + unsigned int i; + int err; + + /* select minimum and maximum rates among the requested rates */ + for (i = 0; i < EMC_RATE_TYPE_MAX; i++, req++) { + if (i == type) { + min_rate = max(new_min_rate, min_rate); + max_rate = min(new_max_rate, max_rate); + } else { + min_rate = max(req->min_rate, min_rate); + max_rate = min(req->max_rate, max_rate); + } + } + + if (min_rate > max_rate) { + dev_err_ratelimited(emc->dev, "%s: type %u: out of range: %lu %lu\n", + __func__, type, min_rate, max_rate); + return -ERANGE; + } + + /* + * EMC rate-changes should go via OPP API because it manages voltage + * changes. + */ + err = dev_pm_opp_set_rate(emc->dev, min_rate); + if (err) + return err; + + emc->requested_rate[type].min_rate = new_min_rate; + emc->requested_rate[type].max_rate = new_max_rate; + + return 0; +} + +static int emc_set_min_rate(struct tegra_emc *emc, unsigned long rate, + enum emc_rate_request_type type) +{ + struct emc_rate_request *req = &emc->requested_rate[type]; + int ret; + + mutex_lock(&emc->rate_lock); + ret = emc_request_rate(emc, rate, req->max_rate, type); + mutex_unlock(&emc->rate_lock); + + return ret; +} + +static int emc_set_max_rate(struct tegra_emc *emc, unsigned long rate, + enum emc_rate_request_type type) +{ + struct emc_rate_request *req = &emc->requested_rate[type]; + int ret; + + mutex_lock(&emc->rate_lock); + ret = emc_request_rate(emc, req->min_rate, rate, type); + mutex_unlock(&emc->rate_lock); + + return ret; +} + +/* + * debugfs interface + * + * The memory controller driver exposes some files in debugfs that can be used + * to control the EMC frequency. The top-level directory can be found here: + * + * /sys/kernel/debug/emc + * + * It contains the following files: + * + * - available_rates: This file contains a list of valid, space-separated + * EMC frequencies. + * + * - min_rate: Writing a value to this file sets the given frequency as the + * floor of the permitted range. If this is higher than the currently + * configured EMC frequency, this will cause the frequency to be + * increased so that it stays within the valid range. + * + * - max_rate: Similarily to the min_rate file, writing a value to this file + * sets the given frequency as the ceiling of the permitted range. If + * the value is lower than the currently configured EMC frequency, this + * will cause the frequency to be decreased so that it stays within the + * valid range. + */ + +static bool tegra_emc_validate_rate(struct tegra_emc *emc, unsigned long rate) +{ + unsigned int i; + + for (i = 0; i < emc->num_timings; i++) + if (rate == emc->timings[i].rate) + return true; + + return false; +} + +static int tegra_emc_debug_available_rates_show(struct seq_file *s, void *data) +{ + struct tegra_emc *emc = s->private; + const char *prefix = ""; + unsigned int i; + + for (i = 0; i < emc->num_timings; i++) { + seq_printf(s, "%s%lu", prefix, emc->timings[i].rate); + prefix = " "; + } + + seq_puts(s, "\n"); + + return 0; +} + +static int tegra_emc_debug_available_rates_open(struct inode *inode, + struct file *file) +{ + return single_open(file, tegra_emc_debug_available_rates_show, + inode->i_private); +} + +static const struct file_operations tegra_emc_debug_available_rates_fops = { + .open = tegra_emc_debug_available_rates_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +static int tegra_emc_debug_min_rate_get(void *data, u64 *rate) +{ + struct tegra_emc *emc = data; + + *rate = emc->debugfs.min_rate; + + return 0; +} + +static int tegra_emc_debug_min_rate_set(void *data, u64 rate) +{ + struct tegra_emc *emc = data; + int err; + + if (!tegra_emc_validate_rate(emc, rate)) + return -EINVAL; + + err = emc_set_min_rate(emc, rate, EMC_RATE_DEBUG); + if (err < 0) + return err; + + emc->debugfs.min_rate = rate; + + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(tegra_emc_debug_min_rate_fops, + tegra_emc_debug_min_rate_get, + tegra_emc_debug_min_rate_set, "%llu\n"); + +static int tegra_emc_debug_max_rate_get(void *data, u64 *rate) +{ + struct tegra_emc *emc = data; + + *rate = emc->debugfs.max_rate; + + return 0; +} + +static int tegra_emc_debug_max_rate_set(void *data, u64 rate) +{ + struct tegra_emc *emc = data; + int err; + + if (!tegra_emc_validate_rate(emc, rate)) + return -EINVAL; + + err = emc_set_max_rate(emc, rate, EMC_RATE_DEBUG); + if (err < 0) + return err; + + emc->debugfs.max_rate = rate; + + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(tegra_emc_debug_max_rate_fops, + tegra_emc_debug_max_rate_get, + tegra_emc_debug_max_rate_set, "%llu\n"); + +static void tegra_emc_debugfs_init(struct tegra_emc *emc) +{ + struct device *dev = emc->dev; + unsigned int i; + int err; + + emc->debugfs.min_rate = ULONG_MAX; + emc->debugfs.max_rate = 0; + + for (i = 0; i < emc->num_timings; i++) { + if (emc->timings[i].rate < emc->debugfs.min_rate) + emc->debugfs.min_rate = emc->timings[i].rate; + + if (emc->timings[i].rate > emc->debugfs.max_rate) + emc->debugfs.max_rate = emc->timings[i].rate; + } + + if (!emc->num_timings) { + emc->debugfs.min_rate = clk_get_rate(emc->clk); + emc->debugfs.max_rate = emc->debugfs.min_rate; + } + + err = clk_set_rate_range(emc->clk, emc->debugfs.min_rate, + emc->debugfs.max_rate); + if (err < 0) { + dev_err(dev, "failed to set rate range [%lu-%lu] for %pC\n", + emc->debugfs.min_rate, emc->debugfs.max_rate, + emc->clk); + } + + emc->debugfs.root = debugfs_create_dir("emc", NULL); + + debugfs_create_file("available_rates", 0444, emc->debugfs.root, + emc, &tegra_emc_debug_available_rates_fops); + debugfs_create_file("min_rate", 0644, emc->debugfs.root, + emc, &tegra_emc_debug_min_rate_fops); + debugfs_create_file("max_rate", 0644, emc->debugfs.root, + emc, &tegra_emc_debug_max_rate_fops); +} + +static inline struct tegra_emc * +to_tegra_emc_provider(struct icc_provider *provider) +{ + return container_of(provider, struct tegra_emc, provider); +} + +static struct icc_node_data * +emc_of_icc_xlate_extended(struct of_phandle_args *spec, void *data) +{ + struct icc_provider *provider = data; + struct icc_node_data *ndata; + struct icc_node *node; + + /* External Memory is the only possible ICC route */ + list_for_each_entry(node, &provider->nodes, node_list) { + if (node->id != TEGRA_ICC_EMEM) + continue; + + ndata = kzalloc(sizeof(*ndata), GFP_KERNEL); + if (!ndata) + return ERR_PTR(-ENOMEM); + + /* + * SRC and DST nodes should have matching TAG in order to have + * it set by default for a requested path. + */ + ndata->tag = TEGRA_MC_ICC_TAG_ISO; + ndata->node = node; + + return ndata; + } + + return ERR_PTR(-EPROBE_DEFER); +} + +static int emc_icc_set(struct icc_node *src, struct icc_node *dst) +{ + struct tegra_emc *emc = to_tegra_emc_provider(dst->provider); + unsigned long long peak_bw = icc_units_to_bps(dst->peak_bw); + unsigned long long avg_bw = icc_units_to_bps(dst->avg_bw); + unsigned long long rate = max(avg_bw, peak_bw); + unsigned int dram_data_bus_width_bytes; + int err; + + /* + * Tegra20 EMC runs on x2 clock rate of SDRAM bus because DDR data + * is sampled on both clock edges. This means that EMC clock rate + * equals to the peak data-rate. + */ + dram_data_bus_width_bytes = emc->dram_bus_width / 8; + do_div(rate, dram_data_bus_width_bytes); + rate = min_t(u64, rate, U32_MAX); + + err = emc_set_min_rate(emc, rate, EMC_RATE_ICC); + if (err) + return err; + + return 0; +} + +static int tegra_emc_interconnect_init(struct tegra_emc *emc) +{ + const struct tegra_mc_soc *soc; + struct icc_node *node; + int err; + + emc->mc = devm_tegra_memory_controller_get(emc->dev); + if (IS_ERR(emc->mc)) + return PTR_ERR(emc->mc); + + soc = emc->mc->soc; + + emc->provider.dev = emc->dev; + emc->provider.set = emc_icc_set; + emc->provider.data = &emc->provider; + emc->provider.aggregate = soc->icc_ops->aggregate; + emc->provider.xlate_extended = emc_of_icc_xlate_extended; + + icc_provider_init(&emc->provider); + + /* create External Memory Controller node */ + node = icc_node_create(TEGRA_ICC_EMC); + if (IS_ERR(node)) { + err = PTR_ERR(node); + goto err_msg; + } + + node->name = "External Memory Controller"; + icc_node_add(node, &emc->provider); + + /* link External Memory Controller to External Memory (DRAM) */ + err = icc_link_create(node, TEGRA_ICC_EMEM); + if (err) + goto remove_nodes; + + /* create External Memory node */ + node = icc_node_create(TEGRA_ICC_EMEM); + if (IS_ERR(node)) { + err = PTR_ERR(node); + goto remove_nodes; + } + + node->name = "External Memory (DRAM)"; + icc_node_add(node, &emc->provider); + + err = icc_provider_register(&emc->provider); + if (err) + goto remove_nodes; + + return 0; + +remove_nodes: + icc_nodes_remove(&emc->provider); +err_msg: + dev_err(emc->dev, "failed to initialize ICC: %d\n", err); + + return err; +} + +static void devm_tegra_emc_unset_callback(void *data) +{ + tegra20_clk_set_emc_round_callback(NULL, NULL); +} + +static void devm_tegra_emc_unreg_clk_notifier(void *data) +{ + struct tegra_emc *emc = data; + + clk_notifier_unregister(emc->clk, &emc->clk_nb); +} + +static int tegra_emc_init_clk(struct tegra_emc *emc) +{ + int err; + + tegra20_clk_set_emc_round_callback(emc_round_rate, emc); + + err = devm_add_action_or_reset(emc->dev, devm_tegra_emc_unset_callback, + NULL); + if (err) + return err; + + emc->clk = devm_clk_get(emc->dev, NULL); + if (IS_ERR(emc->clk)) { + dev_err(emc->dev, "failed to get EMC clock: %pe\n", emc->clk); + return PTR_ERR(emc->clk); + } + + err = clk_notifier_register(emc->clk, &emc->clk_nb); + if (err) { + dev_err(emc->dev, "failed to register clk notifier: %d\n", err); + return err; + } + + err = devm_add_action_or_reset(emc->dev, + devm_tegra_emc_unreg_clk_notifier, emc); + if (err) + return err; + + return 0; +} + +static int tegra_emc_devfreq_target(struct device *dev, unsigned long *freq, + u32 flags) +{ + struct tegra_emc *emc = dev_get_drvdata(dev); + struct dev_pm_opp *opp; + unsigned long rate; + + opp = devfreq_recommended_opp(dev, freq, flags); + if (IS_ERR(opp)) { + dev_err(dev, "failed to find opp for %lu Hz\n", *freq); + return PTR_ERR(opp); + } + + rate = dev_pm_opp_get_freq(opp); + dev_pm_opp_put(opp); + + return emc_set_min_rate(emc, rate, EMC_RATE_DEVFREQ); +} + +static int tegra_emc_devfreq_get_dev_status(struct device *dev, + struct devfreq_dev_status *stat) +{ + struct tegra_emc *emc = dev_get_drvdata(dev); + + /* freeze counters */ + writel_relaxed(EMC_PWR_GATHER_DISABLE, emc->regs + EMC_STAT_CONTROL); + + /* + * busy_time: number of clocks EMC request was accepted + * total_time: number of clocks PWR_GATHER control was set to ENABLE + */ + stat->busy_time = readl_relaxed(emc->regs + EMC_STAT_PWR_COUNT); + stat->total_time = readl_relaxed(emc->regs + EMC_STAT_PWR_CLOCKS); + stat->current_frequency = clk_get_rate(emc->clk); + + /* clear counters and restart */ + writel_relaxed(EMC_PWR_GATHER_CLEAR, emc->regs + EMC_STAT_CONTROL); + writel_relaxed(EMC_PWR_GATHER_ENABLE, emc->regs + EMC_STAT_CONTROL); + + return 0; +} + +static struct devfreq_dev_profile tegra_emc_devfreq_profile = { + .polling_ms = 30, + .target = tegra_emc_devfreq_target, + .get_dev_status = tegra_emc_devfreq_get_dev_status, +}; + +static int tegra_emc_devfreq_init(struct tegra_emc *emc) +{ + struct devfreq *devfreq; + + /* + * PWR_COUNT is 1/2 of PWR_CLOCKS at max, and thus, the up-threshold + * should be less than 50. Secondly, multiple active memory clients + * may cause over 20% of lost clock cycles due to stalls caused by + * competing memory accesses. This means that threshold should be + * set to a less than 30 in order to have a properly working governor. + */ + emc->ondemand_data.upthreshold = 20; + + /* + * Reset statistic gathers state, select global bandwidth for the + * statistics collection mode and set clocks counter saturation + * limit to maximum. + */ + writel_relaxed(0x00000000, emc->regs + EMC_STAT_CONTROL); + writel_relaxed(0x00000000, emc->regs + EMC_STAT_LLMC_CONTROL); + writel_relaxed(0xffffffff, emc->regs + EMC_STAT_PWR_CLOCK_LIMIT); + + devfreq = devm_devfreq_add_device(emc->dev, &tegra_emc_devfreq_profile, + DEVFREQ_GOV_SIMPLE_ONDEMAND, + &emc->ondemand_data); + if (IS_ERR(devfreq)) { + dev_err(emc->dev, "failed to initialize devfreq: %pe", devfreq); + return PTR_ERR(devfreq); + } + + return 0; +} + +static int tegra_emc_probe(struct platform_device *pdev) +{ + struct tegra_core_opp_params opp_params = {}; + struct device_node *np; + struct tegra_emc *emc; + int irq, err; + + irq = platform_get_irq(pdev, 0); + if (irq < 0) { + dev_err(&pdev->dev, "please update your device tree\n"); + return irq; + } + + emc = devm_kzalloc(&pdev->dev, sizeof(*emc), GFP_KERNEL); + if (!emc) + return -ENOMEM; + + mutex_init(&emc->rate_lock); + emc->clk_nb.notifier_call = tegra_emc_clk_change_notify; + emc->dev = &pdev->dev; + + emc->regs = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(emc->regs)) + return PTR_ERR(emc->regs); + + err = emc_setup_hw(emc); + if (err) + return err; + + np = tegra_emc_find_node_by_ram_code(emc); + if (np) { + err = tegra_emc_load_timings_from_dt(emc, np); + of_node_put(np); + if (err) + return err; + } + + err = devm_request_irq(&pdev->dev, irq, tegra_emc_isr, 0, + dev_name(&pdev->dev), emc); + if (err) { + dev_err(&pdev->dev, "failed to request IRQ: %d\n", err); + return err; + } + + err = tegra_emc_init_clk(emc); + if (err) + return err; + + opp_params.init_state = true; + + err = devm_tegra_core_dev_init_opp_table(&pdev->dev, &opp_params); + if (err) + return err; + + platform_set_drvdata(pdev, emc); + tegra_emc_rate_requests_init(emc); + tegra_emc_debugfs_init(emc); + tegra_emc_interconnect_init(emc); + tegra_emc_devfreq_init(emc); + + /* + * Don't allow the kernel module to be unloaded. Unloading adds some + * extra complexity which doesn't really worth the effort in a case of + * this driver. + */ + try_module_get(THIS_MODULE); + + return 0; +} + +static const struct of_device_id tegra_emc_of_match[] = { + { .compatible = "nvidia,tegra20-emc", }, + {}, +}; +MODULE_DEVICE_TABLE(of, tegra_emc_of_match); + +static struct platform_driver tegra_emc_driver = { + .probe = tegra_emc_probe, + .driver = { + .name = "tegra20-emc", + .of_match_table = tegra_emc_of_match, + .suppress_bind_attrs = true, + .sync_state = icc_sync_state, + }, +}; +module_platform_driver(tegra_emc_driver); + +MODULE_AUTHOR("Dmitry Osipenko <digetx@gmail.com>"); +MODULE_DESCRIPTION("NVIDIA Tegra20 EMC driver"); +MODULE_SOFTDEP("pre: governor_simpleondemand"); +MODULE_LICENSE("GPL v2"); |