2024-01-31 00:40:26

by Judith Mendez

[permalink] [raw]
Subject: [RFC PATCH 03/13] drivers: mmc: host: sdhci_am654: Add missing OTAP/ITAP enable

Currently the OTAP/ITAP delay enable functionality is missing in
the am654_set_clock function which is used for MMC0 on AM62p
and AM64x devices. The OTAP delay is not enabled when timing <
SDR25 bus speed mode. The ITAP delay is not enabled for all bus
speed modes.

Add this OTAP/ITAP delay functionality according to the datasheet
[1] OTAPDLYENA and ITAPDLYENA for MMC0.

[1] https://www.ti.com/lit/ds/symlink/am62p.pdf

Signed-off-by: Judith Mendez <[email protected]>
---
drivers/mmc/host/sdhci_am654.c | 48 +++++++++++++++++++---------------
1 file changed, 27 insertions(+), 21 deletions(-)

diff --git a/drivers/mmc/host/sdhci_am654.c b/drivers/mmc/host/sdhci_am654.c
index 0a1ed2ae2eef..35e02f4128a7 100644
--- a/drivers/mmc/host/sdhci_am654.c
+++ b/drivers/mmc/host/sdhci_am654.c
@@ -143,6 +143,7 @@ struct sdhci_am654_data {
struct regmap *base;
int otap_del_sel[ARRAY_SIZE(td)];
int itap_del_sel[ARRAY_SIZE(td)];
+ u8 itap_del_ena[ARRAY_SIZE(td)];
int clkbuf_sel;
int trm_icp;
int drv_strength;
@@ -171,11 +172,13 @@ struct sdhci_am654_driver_data {
};

static void sdhci_am654_write_itapdly(struct sdhci_am654_data *sdhci_am654,
- u32 itapdly)
+ u32 itapdly, u32 enable)
{
/* Set ITAPCHGWIN before writing to ITAPDLY */
regmap_update_bits(sdhci_am654->base, PHY_CTRL4, ITAPCHGWIN_MASK,
0x1 << ITAPCHGWIN_SHIFT);
+ regmap_update_bits(sdhci_am654->base, PHY_CTRL4, ITAPDLYENA_MASK,
+ enable << ITAPDLYENA_SHIFT);
regmap_update_bits(sdhci_am654->base, PHY_CTRL4, ITAPDLYSEL_MASK,
itapdly << ITAPDLYSEL_SHIFT);
regmap_update_bits(sdhci_am654->base, PHY_CTRL4, ITAPCHGWIN_MASK, 0);
@@ -249,7 +252,8 @@ static void sdhci_am654_setup_dll(struct sdhci_host *host, unsigned int clock,
return;
}

- sdhci_am654_write_itapdly(sdhci_am654, sdhci_am654->itap_del_sel[timing]);
+ sdhci_am654_write_itapdly(sdhci_am654, sdhci_am654->itap_del_sel[timing],
+ sdhci_am654->itap_del_ena[timing]);
}

static void sdhci_am654_setup_delay_chain(struct sdhci_am654_data *sdhci_am654,
@@ -263,8 +267,8 @@ static void sdhci_am654_setup_delay_chain(struct sdhci_am654_data *sdhci_am654,
mask = SELDLYTXCLK_MASK | SELDLYRXCLK_MASK;
regmap_update_bits(sdhci_am654->base, PHY_CTRL5, mask, val);

- sdhci_am654_write_itapdly(sdhci_am654,
- sdhci_am654->itap_del_sel[timing]);
+ sdhci_am654_write_itapdly(sdhci_am654, sdhci_am654->itap_del_sel[timing],
+ sdhci_am654->itap_del_ena[timing]);
}

static void sdhci_am654_set_clock(struct sdhci_host *host, unsigned int clock)
@@ -273,20 +277,17 @@ static void sdhci_am654_set_clock(struct sdhci_host *host, unsigned int clock)
struct sdhci_am654_data *sdhci_am654 = sdhci_pltfm_priv(pltfm_host);
unsigned char timing = host->mmc->ios.timing;
u32 otap_del_sel;
- u32 otap_del_ena;
u32 mask, val;

regmap_update_bits(sdhci_am654->base, PHY_CTRL1, ENDLL_MASK, 0);

sdhci_set_clock(host, clock);

- /* Setup DLL Output TAP delay */
+ /* Setup Output TAP delay */
otap_del_sel = sdhci_am654->otap_del_sel[timing];
- otap_del_ena = (timing > MMC_TIMING_UHS_SDR25) ? 1 : 0;

mask = OTAPDLYENA_MASK | OTAPDLYSEL_MASK;
- val = (otap_del_ena << OTAPDLYENA_SHIFT) |
- (otap_del_sel << OTAPDLYSEL_SHIFT);
+ val = (0x1 << OTAPDLYENA_SHIFT) | (otap_del_sel << OTAPDLYSEL_SHIFT);

/* Write to STRBSEL for HS400 speed mode */
if (timing == MMC_TIMING_MMC_HS400) {
@@ -319,14 +320,20 @@ static void sdhci_j721e_4bit_set_clock(struct sdhci_host *host,
struct sdhci_am654_data *sdhci_am654 = sdhci_pltfm_priv(pltfm_host);
unsigned char timing = host->mmc->ios.timing;
u32 otap_del_sel;
+ u32 itap_del_ena;
u32 mask, val;

- /* Setup DLL Output TAP delay */
+ /* Setup Output TAP delay */
otap_del_sel = sdhci_am654->otap_del_sel[timing];

mask = OTAPDLYENA_MASK | OTAPDLYSEL_MASK;
- val = (0x1 << OTAPDLYENA_SHIFT) |
- (otap_del_sel << OTAPDLYSEL_SHIFT);
+ val = (0x1 << OTAPDLYENA_SHIFT) | (otap_del_sel << OTAPDLYSEL_SHIFT);
+
+ itap_del_ena = sdhci_am654->itap_del_ena[timing];
+
+ mask |= ITAPDLYENA_MASK;
+ val |= (itap_del_ena << ITAPDLYENA_SHIFT);
+
regmap_update_bits(sdhci_am654->base, PHY_CTRL4, mask, val);

regmap_update_bits(sdhci_am654->base, PHY_CTRL5, CLKBUFSEL_MASK,
@@ -503,12 +510,8 @@ static int sdhci_am654_platform_execute_tuning(struct sdhci_host *host,
for (i = 0; i < ITAPDLY_LENGTH; i++)
memset(&fail_window[i], 0, sizeof(fail_window[0]));

- /* Enable ITAPDLY */
- regmap_update_bits(sdhci_am654->base, PHY_CTRL4, ITAPDLYENA_MASK,
- 1 << ITAPDLYENA_SHIFT);
-
for (itap = 0; itap < ITAPDLY_LENGTH; itap++) {
- sdhci_am654_write_itapdly(sdhci_am654, itap);
+ sdhci_am654_write_itapdly(sdhci_am654, itap, 1);

curr_pass = !mmc_send_tuning(host->mmc, opcode, NULL);

@@ -532,7 +535,7 @@ static int sdhci_am654_platform_execute_tuning(struct sdhci_host *host,
itap = calculate_itap(host, &fail_window[0], fail_index,
(sdhci_am654->dll_enable ? true : false));

- sdhci_am654_write_itapdly(sdhci_am654, itap);
+ sdhci_am654_write_itapdly(sdhci_am654, itap, 1);

return 0;
}
@@ -681,9 +684,12 @@ static int sdhci_am654_get_otap_delay(struct sdhci_host *host,
host->mmc->caps2 &= ~td[i].capability;
}

- if (td[i].itap_binding)
- device_property_read_u32(dev, td[i].itap_binding,
- &sdhci_am654->itap_del_sel[i]);
+ if (td[i].itap_binding) {
+ ret = device_property_read_u32(dev, td[i].itap_binding,
+ &sdhci_am654->itap_del_sel[i]);
+ if (!ret)
+ sdhci_am654->itap_del_ena[i] = 0x1;
+ }
}

return 0;
--
2.34.1