[PATCH 2/3] mmc: dw_mmc-rockchip: Add v2 tuning support

Detlev Casanova
2024-08-02T15:36:47Z

From: Shawn Lin <shawn.lin@rock-chips.com>

v2 tuning will inherit pre-stage loader's phase settings for the first
time, and do re-tune if necessary.
Re-tune will still try the rough degrees, for instance, 90, 180, 270,
360 but continue to do the fine tuning if sample window isn't good
enough.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
---
drivers/mmc/host/dw_mmc-rockchip.c | 48 ++++++++++++++++++++++++++++++
1 file changed, 48 insertions(+)

diff --git a/drivers/mmc/host/dw_mmc-rockchip.c b/drivers/mmc/host/dw_mmc-rockchip.c
index b07190ba4b7ac..c47b93d99a1b3 100644
--- a/drivers/mmc/host/dw_mmc-rockchip.c
+++ b/drivers/mmc/host/dw_mmc-rockchip.c
@@ -24,6 +24,8 @@ struct dw_mci_rockchip_priv_data {
struct clk *sample_clk;
int default_sample_phase;
int num_phases;
+ bool use_v2_tuning;
+ int last_degree;
};

static void dw_mci_rk3288_set_ios(struct dw_mci *host, struct mmc_ios *ios)
@@ -134,6 +136,42 @@ static void dw_mci_rk3288_set_ios(struct dw_mci *host, struct mmc_ios *ios)
#define TUNING_ITERATION_TO_PHASE(i, num_phases) \
(DIV_ROUND_UP((i) * 360, num_phases))

+static int dw_mci_v2_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
+{
+ struct dw_mci *host = slot->host;
+ struct dw_mci_rockchip_priv_data *priv = host->priv;
+ struct mmc_host *mmc = slot->mmc;
+ u32 degrees[4] = {90, 180, 270, 360};
+ int i;
+ static bool inherit = true;
+
+ if (inherit) {
+ inherit = false;
+ i = clk_get_phase(priv->sample_clk) / 90 - 1;
+ goto done;
+ }
+
+ /* v2 only support 4 degrees in theory */
+ for (i = 0; i < ARRAY_SIZE(degrees); i++) {
+ if (degrees[i] == priv->last_degree)
+ continue;
+
+ clk_set_phase(priv->sample_clk, degrees[i]);
+ if (!mmc_send_tuning(mmc, opcode, NULL))
+ break;
+ }
+
+ if (i == ARRAY_SIZE(degrees)) {
+ dev_warn(host->dev, "All phases bad!");
+ return -EIO;
+ }
+
+done:
+ dev_info(host->dev, "Successfully tuned phase to %d\n", degrees[i]);
+ priv->last_degree = degrees[i];
+ return 0;
+}
+
static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
{
struct dw_mci *host = slot->host;
@@ -157,6 +195,13 @@ static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
return -EIO;
}

+ if (priv->use_v2_tuning) {
+ ret = dw_mci_v2_execute_tuning(slot, opcode);
+ if (!ret)
+ return 0;
+ /* Otherwise we continue using fine tuning */
+ }
+
ranges = kmalloc_array(priv->num_phases / 2 + 1,
sizeof(*ranges), GFP_KERNEL);
if (!ranges)
@@ -277,6 +322,9 @@ static int dw_mci_rk3288_parse_dt(struct dw_mci *host)
&priv->default_sample_phase))
priv->default_sample_phase = 0;

+ if (of_property_read_bool(np, "rockchip,use-v2-tuning"))
+ priv->use_v2_tuning = true;
+
priv->drv_clk = devm_clk_get(host->dev, "ciu-drive");
if (IS_ERR(priv->drv_clk))
dev_dbg(host->dev, "ciu-drive not available\n");
--
2.46.0