// 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");
