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-rw-r--r--drivers/devfreq/sun8i-a33-mbus.c511
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 000000000..13d322131
--- /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");
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-28 10:38:38 +0000