Before, we used syscon to achieve tuning, but the actual measurement
showed little effect, so the tuning implementation was modified here,
and it was realized by reading and writing the UHS_REG_EXT register.
Signed-off-by: William Qiu <william.qiu@xxxxxxxxxxxxxxxx>
Reviewed-by: Emil Renner Berthing <emil.renner.berthing@xxxxxxxxxxxxx>
---
drivers/mmc/host/dw_mmc-starfive.c | 137 +++++++++--------------------
1 file changed, 40 insertions(+), 97 deletions(-)
diff --git a/drivers/mmc/host/dw_mmc-starfive.c b/drivers/mmc/host/dw_mmc-starfive.c
index fd05a648a8bb..b4d81ef0f3af 100644
--- a/drivers/mmc/host/dw_mmc-starfive.c
+++ b/drivers/mmc/host/dw_mmc-starfive.c
@@ -5,6 +5,7 @@
* Copyright (c) 2022 StarFive Technology Co., Ltd.
*/
+#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/mfd/syscon.h>
@@ -20,13 +21,7 @@
#define ALL_INT_CLR 0x1ffff
#define MAX_DELAY_CHAIN 32
-struct starfive_priv {
- struct device *dev;
- struct regmap *reg_syscon;
- u32 syscon_offset;
- u32 syscon_shift;
- u32 syscon_mask;
-};
+#define STARFIVE_SMPL_PHASE GENMASK(20, 16)
static void dw_mci_starfive_set_ios(struct dw_mci *host, struct mmc_ios *ios)
{
@@ -44,117 +39,65 @@ static void dw_mci_starfive_set_ios(struct dw_mci *host, struct mmc_ios *ios)
}
}
+static void dw_mci_starfive_set_sample_phase(struct dw_mci *host, u32 smpl_phase)
+{
+ /* change driver phase and sample phase */
+ u32 reg_value = mci_readl(host, UHS_REG_EXT);
+
+ /* In UHS_REG_EXT, only 5 bits valid in DRV_PHASE and SMPL_PHASE */
+ reg_value &= ~STARFIVE_SMPL_PHASE;
+ reg_value |= FIELD_PREP(STARFIVE_SMPL_PHASE, smpl_phase);
+ mci_writel(host, UHS_REG_EXT, reg_value);
+
+ /* We should delay 1ms wait for timing setting finished. */
+ mdelay(1);
+}
+
static int dw_mci_starfive_execute_tuning(struct dw_mci_slot *slot,
u32 opcode)
{
static const int grade = MAX_DELAY_CHAIN;
struct dw_mci *host = slot->host;
- struct starfive_priv *priv = host->priv;
- int rise_point = -1, fall_point = -1;
- int err, prev_err = 0;
- int i;
- bool found = 0;
- u32 regval;
-
- /*
- * Use grade as the max delay chain, and use the rise_point and
- * fall_point to ensure the best sampling point of a data input
- * signals.
- */
- for (i = 0; i < grade; i++) {
- regval = i << priv->syscon_shift;
- err = regmap_update_bits(priv->reg_syscon, priv->syscon_offset,
- priv->syscon_mask, regval);
- if (err)
- return err;
+ int smpl_phase, smpl_raise = -1, smpl_fall = -1;
+ int ret;
+
+ for (smpl_phase = 0; smpl_phase < grade; smpl_phase++) {
+ dw_mci_starfive_set_sample_phase(host, smpl_phase);
mci_writel(host, RINTSTS, ALL_INT_CLR);
- err = mmc_send_tuning(slot->mmc, opcode, NULL);
- if (!err)
- found = 1;
+ ret = mmc_send_tuning(slot->mmc, opcode, NULL);
- if (i > 0) {
- if (err && !prev_err)
- fall_point = i - 1;
- if (!err && prev_err)
- rise_point = i;
+ if (!ret && smpl_raise < 0) {
+ smpl_raise = smpl_phase;
+ } else if (ret && smpl_raise >= 0) {
+ smpl_fall = smpl_phase - 1;
+ break;
}
-
- if (rise_point != -1 && fall_point != -1)
- goto tuning_out;
-
- prev_err = err;
- err = 0;
}
-tuning_out:
- if (found) {
- if (rise_point == -1)
- rise_point = 0;
- if (fall_point == -1)
- fall_point = grade - 1;
- if (fall_point < rise_point) {
- if ((rise_point + fall_point) >
- (grade - 1))
- i = fall_point / 2;
- else
- i = (rise_point + grade - 1) / 2;
- } else {
- i = (rise_point + fall_point) / 2;
- }
-
- regval = i << priv->syscon_shift;
- err = regmap_update_bits(priv->reg_syscon, priv->syscon_offset,
- priv->syscon_mask, regval);
- if (err)
- return err;
- mci_writel(host, RINTSTS, ALL_INT_CLR);
+ if (smpl_phase >= grade)
+ smpl_fall = grade - 1;
- dev_info(host->dev, "Found valid delay chain! use it [delay=%d]\n", i);
- } else {
+ if (smpl_raise < 0) {
+ smpl_phase = 0;
dev_err(host->dev, "No valid delay chain! use default\n");
- err = -EINVAL;
+ ret = -EINVAL;
+ goto out;
}
- mci_writel(host, RINTSTS, ALL_INT_CLR);
- return err;
-}
-
-static int dw_mci_starfive_parse_dt(struct dw_mci *host)
-{
- struct of_phandle_args args;
- struct starfive_priv *priv;
- int ret;
-
- priv = devm_kzalloc(host->dev, sizeof(*priv), GFP_KERNEL);
- if (!priv)
- return -ENOMEM;
+ smpl_phase = (smpl_raise + smpl_fall) / 2;
+ dev_dbg(host->dev, "Found valid delay chain! use it [delay=%d]\n", smpl_phase);
+ ret = 0;
- ret = of_parse_phandle_with_fixed_args(host->dev->of_node,
- "starfive,sysreg", 3, 0, &args);
- if (ret) {
- dev_err(host->dev, "Failed to parse starfive,sysreg\n");
- return -EINVAL;
- }
-
- priv->reg_syscon = syscon_node_to_regmap(args.np);
- of_node_put(args.np);
- if (IS_ERR(priv->reg_syscon))
- return PTR_ERR(priv->reg_syscon);
-
- priv->syscon_offset = args.args[0];
- priv->syscon_shift = args.args[1];
- priv->syscon_mask = args.args[2];
-
- host->priv = priv;
-
- return 0;
+out:
+ dw_mci_starfive_set_sample_phase(host, smpl_phase);
+ mci_writel(host, RINTSTS, ALL_INT_CLR);
+ return ret;
}
static const struct dw_mci_drv_data starfive_data = {
.common_caps = MMC_CAP_CMD23,
.set_ios = dw_mci_starfive_set_ios,
- .parse_dt = dw_mci_starfive_parse_dt,
.execute_tuning = dw_mci_starfive_execute_tuning,
};
--
2.34.1
