diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/devfreq/sun8i-a33-mbus.c | 511 |
1 files changed, 511 insertions, 0 deletions
diff --git a/drivers/devfreq/sun8i-a33-mbus.c b/drivers/devfreq/sun8i-a33-mbus.c new file mode 100644 index 000000000000..13d32213139f --- /dev/null +++ b/drivers/devfreq/sun8i-a33-mbus.c @@ -0,0 +1,511 @@ +// SPDX-License-Identifier: GPL-2.0-only +// +// Copyright (C) 2020-2021 Samuel Holland <samuel@sholland.org> +// + +#include <linux/clk.h> +#include <linux/devfreq.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/iopoll.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/property.h> + +#define MBUS_CR 0x0000 +#define MBUS_CR_GET_DRAM_TYPE(x) (((x) >> 16) & 0x7) +#define MBUS_CR_DRAM_TYPE_DDR2 2 +#define MBUS_CR_DRAM_TYPE_DDR3 3 +#define MBUS_CR_DRAM_TYPE_DDR4 4 +#define MBUS_CR_DRAM_TYPE_LPDDR2 6 +#define MBUS_CR_DRAM_TYPE_LPDDR3 7 + +#define MBUS_TMR 0x000c +#define MBUS_TMR_PERIOD(x) ((x) - 1) + +#define MBUS_PMU_CFG 0x009c +#define MBUS_PMU_CFG_PERIOD(x) (((x) - 1) << 16) +#define MBUS_PMU_CFG_UNIT (0x3 << 1) +#define MBUS_PMU_CFG_UNIT_B (0x0 << 1) +#define MBUS_PMU_CFG_UNIT_KB (0x1 << 1) +#define MBUS_PMU_CFG_UNIT_MB (0x2 << 1) +#define MBUS_PMU_CFG_ENABLE (0x1 << 0) + +#define MBUS_PMU_BWCR(n) (0x00a0 + (0x04 * (n))) + +#define MBUS_TOTAL_BWCR MBUS_PMU_BWCR(5) +#define MBUS_TOTAL_BWCR_H616 MBUS_PMU_BWCR(13) + +#define MBUS_MDFSCR 0x0100 +#define MBUS_MDFSCR_BUFFER_TIMING (0x1 << 15) +#define MBUS_MDFSCR_PAD_HOLD (0x1 << 13) +#define MBUS_MDFSCR_BYPASS (0x1 << 4) +#define MBUS_MDFSCR_MODE (0x1 << 1) +#define MBUS_MDFSCR_MODE_DFS (0x0 << 1) +#define MBUS_MDFSCR_MODE_CFS (0x1 << 1) +#define MBUS_MDFSCR_START (0x1 << 0) + +#define MBUS_MDFSMRMR 0x0108 + +#define DRAM_PWRCTL 0x0004 +#define DRAM_PWRCTL_SELFREF_EN (0x1 << 0) + +#define DRAM_RFSHTMG 0x0090 +#define DRAM_RFSHTMG_TREFI(x) ((x) << 16) +#define DRAM_RFSHTMG_TRFC(x) ((x) << 0) + +#define DRAM_VTFCR 0x00b8 +#define DRAM_VTFCR_VTF_ENABLE (0x3 << 8) + +#define DRAM_ODTMAP 0x0120 + +#define DRAM_DX_MAX 4 + +#define DRAM_DXnGCR0(n) (0x0344 + 0x80 * (n)) +#define DRAM_DXnGCR0_DXODT (0x3 << 4) +#define DRAM_DXnGCR0_DXODT_DYNAMIC (0x0 << 4) +#define DRAM_DXnGCR0_DXODT_ENABLED (0x1 << 4) +#define DRAM_DXnGCR0_DXODT_DISABLED (0x2 << 4) +#define DRAM_DXnGCR0_DXEN (0x1 << 0) + +struct sun8i_a33_mbus_variant { + u32 min_dram_divider; + u32 max_dram_divider; + u32 odt_freq_mhz; +}; + +struct sun8i_a33_mbus { + const struct sun8i_a33_mbus_variant *variant; + void __iomem *reg_dram; + void __iomem *reg_mbus; + struct clk *clk_bus; + struct clk *clk_dram; + struct clk *clk_mbus; + struct devfreq *devfreq_dram; + struct devfreq_simple_ondemand_data gov_data; + struct devfreq_dev_profile profile; + u32 data_width; + u32 nominal_bw; + u32 odtmap; + u32 tREFI_ns; + u32 tRFC_ns; + unsigned long freq_table[]; +}; + +/* + * The unit for this value is (MBUS clock cycles / MBUS_TMR_PERIOD). When + * MBUS_TMR_PERIOD is programmed to match the MBUS clock frequency in MHz, as + * it is during DRAM init and during probe, the resulting unit is microseconds. + */ +static int pmu_period = 50000; +module_param(pmu_period, int, 0644); +MODULE_PARM_DESC(pmu_period, "Bandwidth measurement period (microseconds)"); + +static u32 sun8i_a33_mbus_get_peak_bw(struct sun8i_a33_mbus *priv) +{ + /* Returns the peak transfer (in KiB) during any single PMU period. */ + return readl_relaxed(priv->reg_mbus + MBUS_TOTAL_BWCR); +} + +static void sun8i_a33_mbus_restart_pmu_counters(struct sun8i_a33_mbus *priv) +{ + u32 pmu_cfg = MBUS_PMU_CFG_PERIOD(pmu_period) | MBUS_PMU_CFG_UNIT_KB; + + /* All PMU counters are cleared on a disable->enable transition. */ + writel_relaxed(pmu_cfg, + priv->reg_mbus + MBUS_PMU_CFG); + writel_relaxed(pmu_cfg | MBUS_PMU_CFG_ENABLE, + priv->reg_mbus + MBUS_PMU_CFG); + +} + +static void sun8i_a33_mbus_update_nominal_bw(struct sun8i_a33_mbus *priv, + u32 ddr_freq_mhz) +{ + /* + * Nominal bandwidth (KiB per PMU period): + * + * DDR transfers microseconds KiB + * ------------- * ------------ * -------- + * microsecond PMU period transfer + */ + priv->nominal_bw = ddr_freq_mhz * pmu_period * priv->data_width / 1024; +} + +static int sun8i_a33_mbus_set_dram_freq(struct sun8i_a33_mbus *priv, + unsigned long freq) +{ + u32 ddr_freq_mhz = freq / USEC_PER_SEC; /* DDR */ + u32 dram_freq_mhz = ddr_freq_mhz / 2; /* SDR */ + u32 mctl_freq_mhz = dram_freq_mhz / 2; /* HDR */ + u32 dxodt, mdfscr, pwrctl, vtfcr; + u32 i, tREFI_32ck, tRFC_ck; + int ret; + + /* The rate change is not effective until the MDFS process runs. */ + ret = clk_set_rate(priv->clk_dram, freq); + if (ret) + return ret; + + /* Disable automatic self-refesh and VTF before starting MDFS. */ + pwrctl = readl_relaxed(priv->reg_dram + DRAM_PWRCTL) & + ~DRAM_PWRCTL_SELFREF_EN; + writel_relaxed(pwrctl, priv->reg_dram + DRAM_PWRCTL); + vtfcr = readl_relaxed(priv->reg_dram + DRAM_VTFCR); + writel_relaxed(vtfcr & ~DRAM_VTFCR_VTF_ENABLE, + priv->reg_dram + DRAM_VTFCR); + + /* Set up MDFS and enable double buffering for timing registers. */ + mdfscr = MBUS_MDFSCR_MODE_DFS | + MBUS_MDFSCR_BYPASS | + MBUS_MDFSCR_PAD_HOLD | + MBUS_MDFSCR_BUFFER_TIMING; + writel(mdfscr, priv->reg_mbus + MBUS_MDFSCR); + + /* Update the buffered copy of RFSHTMG. */ + tREFI_32ck = priv->tREFI_ns * mctl_freq_mhz / 1000 / 32; + tRFC_ck = DIV_ROUND_UP(priv->tRFC_ns * mctl_freq_mhz, 1000); + writel(DRAM_RFSHTMG_TREFI(tREFI_32ck) | DRAM_RFSHTMG_TRFC(tRFC_ck), + priv->reg_dram + DRAM_RFSHTMG); + + /* Enable ODT if needed, or disable it to save power. */ + if (priv->odtmap && dram_freq_mhz > priv->variant->odt_freq_mhz) { + dxodt = DRAM_DXnGCR0_DXODT_DYNAMIC; + writel(priv->odtmap, priv->reg_dram + DRAM_ODTMAP); + } else { + dxodt = DRAM_DXnGCR0_DXODT_DISABLED; + writel(0, priv->reg_dram + DRAM_ODTMAP); + } + for (i = 0; i < DRAM_DX_MAX; ++i) { + void __iomem *reg = priv->reg_dram + DRAM_DXnGCR0(i); + + writel((readl(reg) & ~DRAM_DXnGCR0_DXODT) | dxodt, reg); + } + + dev_dbg(priv->devfreq_dram->dev.parent, + "Setting DRAM to %u MHz, tREFI=%u, tRFC=%u, ODT=%s\n", + dram_freq_mhz, tREFI_32ck, tRFC_ck, + dxodt == DRAM_DXnGCR0_DXODT_DYNAMIC ? "dynamic" : "disabled"); + + /* Trigger hardware MDFS. */ + writel(mdfscr | MBUS_MDFSCR_START, priv->reg_mbus + MBUS_MDFSCR); + ret = readl_poll_timeout_atomic(priv->reg_mbus + MBUS_MDFSCR, mdfscr, + !(mdfscr & MBUS_MDFSCR_START), 10, 1000); + if (ret) + return ret; + + /* Disable double buffering. */ + writel(0, priv->reg_mbus + MBUS_MDFSCR); + + /* Restore VTF configuration. */ + writel_relaxed(vtfcr, priv->reg_dram + DRAM_VTFCR); + + /* Enable automatic self-refresh at the lowest frequency only. */ + if (freq == priv->freq_table[0]) + pwrctl |= DRAM_PWRCTL_SELFREF_EN; + writel_relaxed(pwrctl, priv->reg_dram + DRAM_PWRCTL); + + sun8i_a33_mbus_restart_pmu_counters(priv); + sun8i_a33_mbus_update_nominal_bw(priv, ddr_freq_mhz); + + return 0; +} + +static int sun8i_a33_mbus_set_dram_target(struct device *dev, + unsigned long *freq, u32 flags) +{ + struct sun8i_a33_mbus *priv = dev_get_drvdata(dev); + struct devfreq *devfreq = priv->devfreq_dram; + struct dev_pm_opp *opp; + int ret; + + opp = devfreq_recommended_opp(dev, freq, flags); + if (IS_ERR(opp)) + return PTR_ERR(opp); + + dev_pm_opp_put(opp); + + if (*freq == devfreq->previous_freq) + return 0; + + ret = sun8i_a33_mbus_set_dram_freq(priv, *freq); + if (ret) { + dev_warn(dev, "failed to set DRAM frequency: %d\n", ret); + *freq = devfreq->previous_freq; + } + + return ret; +} + +static int sun8i_a33_mbus_get_dram_status(struct device *dev, + struct devfreq_dev_status *stat) +{ + struct sun8i_a33_mbus *priv = dev_get_drvdata(dev); + + stat->busy_time = sun8i_a33_mbus_get_peak_bw(priv); + stat->total_time = priv->nominal_bw; + stat->current_frequency = priv->devfreq_dram->previous_freq; + + sun8i_a33_mbus_restart_pmu_counters(priv); + + dev_dbg(dev, "Using %lu/%lu (%lu%%) at %lu MHz\n", + stat->busy_time, stat->total_time, + DIV_ROUND_CLOSEST(stat->busy_time * 100, stat->total_time), + stat->current_frequency / USEC_PER_SEC); + + return 0; +} + +static int sun8i_a33_mbus_hw_init(struct device *dev, + struct sun8i_a33_mbus *priv, + unsigned long ddr_freq) +{ + u32 i, mbus_cr, mbus_freq_mhz; + + /* Choose tREFI and tRFC to match the configured DRAM type. */ + mbus_cr = readl_relaxed(priv->reg_mbus + MBUS_CR); + switch (MBUS_CR_GET_DRAM_TYPE(mbus_cr)) { + case MBUS_CR_DRAM_TYPE_DDR2: + case MBUS_CR_DRAM_TYPE_DDR3: + case MBUS_CR_DRAM_TYPE_DDR4: + priv->tREFI_ns = 7800; + priv->tRFC_ns = 350; + break; + case MBUS_CR_DRAM_TYPE_LPDDR2: + case MBUS_CR_DRAM_TYPE_LPDDR3: + priv->tREFI_ns = 3900; + priv->tRFC_ns = 210; + break; + default: + return -EINVAL; + } + + /* Save ODTMAP so it can be restored when raising the frequency. */ + priv->odtmap = readl_relaxed(priv->reg_dram + DRAM_ODTMAP); + + /* Compute the DRAM data bus width by counting enabled DATx8 blocks. */ + for (i = 0; i < DRAM_DX_MAX; ++i) { + void __iomem *reg = priv->reg_dram + DRAM_DXnGCR0(i); + + if (!(readl_relaxed(reg) & DRAM_DXnGCR0_DXEN)) + break; + } + priv->data_width = i; + + dev_dbg(dev, "Detected %u-bit %sDDRx with%s ODT\n", + priv->data_width * 8, + MBUS_CR_GET_DRAM_TYPE(mbus_cr) > 4 ? "LP" : "", + priv->odtmap ? "" : "out"); + + /* Program MBUS_TMR such that the PMU period unit is microseconds. */ + mbus_freq_mhz = clk_get_rate(priv->clk_mbus) / USEC_PER_SEC; + writel_relaxed(MBUS_TMR_PERIOD(mbus_freq_mhz), + priv->reg_mbus + MBUS_TMR); + + /* "Master Ready Mask Register" bits must be set or MDFS will block. */ + writel_relaxed(0xffffffff, priv->reg_mbus + MBUS_MDFSMRMR); + + sun8i_a33_mbus_restart_pmu_counters(priv); + sun8i_a33_mbus_update_nominal_bw(priv, ddr_freq / USEC_PER_SEC); + + return 0; +} + +static int __maybe_unused sun8i_a33_mbus_suspend(struct device *dev) +{ + struct sun8i_a33_mbus *priv = dev_get_drvdata(dev); + + clk_disable_unprepare(priv->clk_bus); + + return 0; +} + +static int __maybe_unused sun8i_a33_mbus_resume(struct device *dev) +{ + struct sun8i_a33_mbus *priv = dev_get_drvdata(dev); + + return clk_prepare_enable(priv->clk_bus); +} + +static int sun8i_a33_mbus_probe(struct platform_device *pdev) +{ + const struct sun8i_a33_mbus_variant *variant; + struct device *dev = &pdev->dev; + struct sun8i_a33_mbus *priv; + unsigned long base_freq; + unsigned int max_state; + const char *err; + int i, ret; + + variant = device_get_match_data(dev); + if (!variant) + return -EINVAL; + + max_state = variant->max_dram_divider - variant->min_dram_divider + 1; + + priv = devm_kzalloc(dev, struct_size(priv, freq_table, max_state), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + platform_set_drvdata(pdev, priv); + + priv->variant = variant; + + priv->reg_dram = devm_platform_ioremap_resource_byname(pdev, "dram"); + if (IS_ERR(priv->reg_dram)) + return PTR_ERR(priv->reg_dram); + + priv->reg_mbus = devm_platform_ioremap_resource_byname(pdev, "mbus"); + if (IS_ERR(priv->reg_mbus)) + return PTR_ERR(priv->reg_mbus); + + priv->clk_bus = devm_clk_get(dev, "bus"); + if (IS_ERR(priv->clk_bus)) + return dev_err_probe(dev, PTR_ERR(priv->clk_bus), + "failed to get bus clock\n"); + + priv->clk_dram = devm_clk_get(dev, "dram"); + if (IS_ERR(priv->clk_dram)) + return dev_err_probe(dev, PTR_ERR(priv->clk_dram), + "failed to get dram clock\n"); + + priv->clk_mbus = devm_clk_get(dev, "mbus"); + if (IS_ERR(priv->clk_mbus)) + return dev_err_probe(dev, PTR_ERR(priv->clk_mbus), + "failed to get mbus clock\n"); + + ret = clk_prepare_enable(priv->clk_bus); + if (ret) + return dev_err_probe(dev, ret, + "failed to enable bus clock\n"); + + /* Lock the DRAM clock rate to keep priv->nominal_bw in sync. */ + ret = clk_rate_exclusive_get(priv->clk_dram); + if (ret) { + err = "failed to lock dram clock rate\n"; + goto err_disable_bus; + } + + /* Lock the MBUS clock rate to keep MBUS_TMR_PERIOD in sync. */ + ret = clk_rate_exclusive_get(priv->clk_mbus); + if (ret) { + err = "failed to lock mbus clock rate\n"; + goto err_unlock_dram; + } + + priv->gov_data.upthreshold = 10; + priv->gov_data.downdifferential = 5; + + priv->profile.initial_freq = clk_get_rate(priv->clk_dram); + priv->profile.polling_ms = 1000; + priv->profile.target = sun8i_a33_mbus_set_dram_target; + priv->profile.get_dev_status = sun8i_a33_mbus_get_dram_status; + priv->profile.freq_table = priv->freq_table; + priv->profile.max_state = max_state; + + ret = devm_pm_opp_set_clkname(dev, "dram"); + if (ret) { + err = "failed to add OPP table\n"; + goto err_unlock_mbus; + } + + base_freq = clk_get_rate(clk_get_parent(priv->clk_dram)); + for (i = 0; i < max_state; ++i) { + unsigned int div = variant->max_dram_divider - i; + + priv->freq_table[i] = base_freq / div; + + ret = dev_pm_opp_add(dev, priv->freq_table[i], 0); + if (ret) { + err = "failed to add OPPs\n"; + goto err_remove_opps; + } + } + + ret = sun8i_a33_mbus_hw_init(dev, priv, priv->profile.initial_freq); + if (ret) { + err = "failed to init hardware\n"; + goto err_remove_opps; + } + + priv->devfreq_dram = devfreq_add_device(dev, &priv->profile, + DEVFREQ_GOV_SIMPLE_ONDEMAND, + &priv->gov_data); + if (IS_ERR(priv->devfreq_dram)) { + ret = PTR_ERR(priv->devfreq_dram); + err = "failed to add devfreq device\n"; + goto err_remove_opps; + } + + /* + * This must be set manually after registering the devfreq device, + * because there is no way to select a dynamic OPP as the suspend OPP. + */ + priv->devfreq_dram->suspend_freq = priv->freq_table[0]; + + return 0; + +err_remove_opps: + dev_pm_opp_remove_all_dynamic(dev); +err_unlock_mbus: + clk_rate_exclusive_put(priv->clk_mbus); +err_unlock_dram: + clk_rate_exclusive_put(priv->clk_dram); +err_disable_bus: + clk_disable_unprepare(priv->clk_bus); + + return dev_err_probe(dev, ret, err); +} + +static int sun8i_a33_mbus_remove(struct platform_device *pdev) +{ + struct sun8i_a33_mbus *priv = platform_get_drvdata(pdev); + unsigned long initial_freq = priv->profile.initial_freq; + struct device *dev = &pdev->dev; + int ret; + + devfreq_remove_device(priv->devfreq_dram); + + ret = sun8i_a33_mbus_set_dram_freq(priv, initial_freq); + if (ret) + dev_warn(dev, "failed to restore DRAM frequency: %d\n", ret); + + dev_pm_opp_remove_all_dynamic(dev); + clk_rate_exclusive_put(priv->clk_mbus); + clk_rate_exclusive_put(priv->clk_dram); + clk_disable_unprepare(priv->clk_bus); + + return 0; +} + +static const struct sun8i_a33_mbus_variant sun50i_a64_mbus = { + .min_dram_divider = 1, + .max_dram_divider = 4, + .odt_freq_mhz = 400, +}; + +static const struct of_device_id sun8i_a33_mbus_of_match[] = { + { .compatible = "allwinner,sun50i-a64-mbus", .data = &sun50i_a64_mbus }, + { .compatible = "allwinner,sun50i-h5-mbus", .data = &sun50i_a64_mbus }, + { }, +}; +MODULE_DEVICE_TABLE(of, sun8i_a33_mbus_of_match); + +static SIMPLE_DEV_PM_OPS(sun8i_a33_mbus_pm_ops, + sun8i_a33_mbus_suspend, sun8i_a33_mbus_resume); + +static struct platform_driver sun8i_a33_mbus_driver = { + .probe = sun8i_a33_mbus_probe, + .remove = sun8i_a33_mbus_remove, + .driver = { + .name = "sun8i-a33-mbus", + .of_match_table = sun8i_a33_mbus_of_match, + .pm = pm_ptr(&sun8i_a33_mbus_pm_ops), + }, +}; +module_platform_driver(sun8i_a33_mbus_driver); + +MODULE_AUTHOR("Samuel Holland <samuel@sholland.org>"); +MODULE_DESCRIPTION("Allwinner sun8i/sun50i MBUS DEVFREQ Driver"); +MODULE_LICENSE("GPL v2"); |