[PATCH v2 2/4] sdhci: arasan: Add support for Versal Tap Delays

From: Manish Narani
Date: Mon Mar 30 2020 - 01:42:33 EST


Add support to set tap delays for Xilinx Versal SD controller. The tap
delay registers have moved to SD controller space in Versal. Make the
changes accordingly.

Signed-off-by: Manish Narani <manish.narani@xxxxxxxxxx>
---
drivers/mmc/host/sdhci-of-arasan.c | 175 +++++++++++++++++++++++++++++
1 file changed, 175 insertions(+)

diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
index 0146d7dd315b..34403b2cac97 100644
--- a/drivers/mmc/host/sdhci-of-arasan.c
+++ b/drivers/mmc/host/sdhci-of-arasan.c
@@ -28,15 +28,26 @@
#include "sdhci-pltfm.h"

#define SDHCI_ARASAN_VENDOR_REGISTER 0x78
+
+#define SDHCI_ARASAN_ITAPDLY_REGISTER 0xF0F8
+#define SDHCI_ARASAN_OTAPDLY_REGISTER 0xF0FC
+
#define SDHCI_ARASAN_CQE_BASE_ADDR 0x200
#define VENDOR_ENHANCED_STROBE BIT(0)

#define PHY_CLK_TOO_SLOW_HZ 400000

+#define SDHCI_ITAPDLY_CHGWIN 0x200
+#define SDHCI_ITAPDLY_ENABLE 0x100
+#define SDHCI_OTAPDLY_ENABLE 0x40
+
/* Default settings for ZynqMP Clock Phases */
#define ZYNQMP_ICLK_PHASE {0, 63, 63, 0, 63, 0, 0, 183, 54, 0, 0}
#define ZYNQMP_OCLK_PHASE {0, 72, 60, 0, 60, 72, 135, 48, 72, 135, 0}

+#define VERSAL_ICLK_PHASE {0, 132, 132, 0, 132, 0, 0, 162, 90, 0, 0}
+#define VERSAL_OCLK_PHASE {0, 60, 48, 0, 48, 72, 90, 36, 60, 90, 0}
+
/*
* On some SoCs the syscon area has a feature where the upper 16-bits of
* each 32-bit register act as a write mask for the lower 16-bits. This allows
@@ -566,6 +577,10 @@ static const struct of_device_id sdhci_arasan_of_match[] = {
.compatible = "xlnx,zynqmp-8.9a",
.data = &sdhci_arasan_zynqmp_data,
},
+ {
+ .compatible = "xlnx,versal-8.9a",
+ .data = &sdhci_arasan_zynqmp_data,
+ },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, sdhci_arasan_of_match);
@@ -768,6 +783,152 @@ static const struct clk_ops zynqmp_sampleclk_ops = {
.set_phase = sdhci_zynqmp_sampleclk_set_phase,
};

+/**
+ * sdhci_versal_sdcardclk_set_phase - Set the SD Output Clock Tap Delays
+ *
+ * Set the SD Output Clock Tap Delays for Output path
+ *
+ * @hw: Pointer to the hardware clock structure.
+ * @degrees The clock phase shift between 0 - 359.
+ * Return: 0 on success and error value on error
+ */
+static int sdhci_versal_sdcardclk_set_phase(struct clk_hw *hw, int degrees)
+{
+ struct sdhci_arasan_clk_data *clk_data =
+ container_of(hw, struct sdhci_arasan_clk_data, sdcardclk_hw);
+ struct sdhci_arasan_data *sdhci_arasan =
+ container_of(clk_data, struct sdhci_arasan_data, clk_data);
+ struct sdhci_host *host = sdhci_arasan->host;
+ u8 tap_delay, tap_max = 0;
+ int ret;
+
+ /*
+ * This is applicable for SDHCI_SPEC_300 and above
+ * Versal does not set phase for <=25MHz clock.
+ * If degrees is zero, no need to do anything.
+ */
+ if (host->version < SDHCI_SPEC_300 ||
+ host->timing == MMC_TIMING_LEGACY ||
+ host->timing == MMC_TIMING_UHS_SDR12 || !degrees)
+ return 0;
+
+ switch (host->timing) {
+ case MMC_TIMING_MMC_HS:
+ case MMC_TIMING_SD_HS:
+ case MMC_TIMING_UHS_SDR25:
+ case MMC_TIMING_UHS_DDR50:
+ case MMC_TIMING_MMC_DDR52:
+ /* For 50MHz clock, 30 Taps are available */
+ tap_max = 30;
+ break;
+ case MMC_TIMING_UHS_SDR50:
+ /* For 100MHz clock, 15 Taps are available */
+ tap_max = 15;
+ break;
+ case MMC_TIMING_UHS_SDR104:
+ case MMC_TIMING_MMC_HS200:
+ /* For 200MHz clock, 8 Taps are available */
+ tap_max = 8;
+ default:
+ break;
+ }
+
+ tap_delay = (degrees * tap_max) / 360;
+
+ /* Set the Clock Phase */
+ if (tap_delay) {
+ u32 regval;
+
+ regval = sdhci_readl(host, SDHCI_ARASAN_OTAPDLY_REGISTER);
+ regval |= SDHCI_OTAPDLY_ENABLE;
+ sdhci_writel(host, regval, SDHCI_ARASAN_OTAPDLY_REGISTER);
+ regval |= tap_delay;
+ sdhci_writel(host, regval, SDHCI_ARASAN_OTAPDLY_REGISTER);
+ }
+
+ return ret;
+}
+
+static const struct clk_ops versal_sdcardclk_ops = {
+ .recalc_rate = sdhci_arasan_sdcardclk_recalc_rate,
+ .set_phase = sdhci_versal_sdcardclk_set_phase,
+};
+
+/**
+ * sdhci_versal_sampleclk_set_phase - Set the SD Input Clock Tap Delays
+ *
+ * Set the SD Input Clock Tap Delays for Input path
+ *
+ * @hw: Pointer to the hardware clock structure.
+ * @degrees The clock phase shift between 0 - 359.
+ * Return: 0 on success and error value on error
+ */
+static int sdhci_versal_sampleclk_set_phase(struct clk_hw *hw, int degrees)
+{
+ struct sdhci_arasan_clk_data *clk_data =
+ container_of(hw, struct sdhci_arasan_clk_data, sampleclk_hw);
+ struct sdhci_arasan_data *sdhci_arasan =
+ container_of(clk_data, struct sdhci_arasan_data, clk_data);
+ struct sdhci_host *host = sdhci_arasan->host;
+ u8 tap_delay, tap_max = 0;
+ int ret;
+
+ /*
+ * This is applicable for SDHCI_SPEC_300 and above
+ * Versal does not set phase for <=25MHz clock.
+ * If degrees is zero, no need to do anything.
+ */
+ if (host->version < SDHCI_SPEC_300 ||
+ host->timing == MMC_TIMING_LEGACY ||
+ host->timing == MMC_TIMING_UHS_SDR12 || !degrees)
+ return 0;
+
+ switch (host->timing) {
+ case MMC_TIMING_MMC_HS:
+ case MMC_TIMING_SD_HS:
+ case MMC_TIMING_UHS_SDR25:
+ case MMC_TIMING_UHS_DDR50:
+ case MMC_TIMING_MMC_DDR52:
+ /* For 50MHz clock, 120 Taps are available */
+ tap_max = 120;
+ break;
+ case MMC_TIMING_UHS_SDR50:
+ /* For 100MHz clock, 60 Taps are available */
+ tap_max = 60;
+ break;
+ case MMC_TIMING_UHS_SDR104:
+ case MMC_TIMING_MMC_HS200:
+ /* For 200MHz clock, 30 Taps are available */
+ tap_max = 30;
+ default:
+ break;
+ }
+
+ tap_delay = (degrees * tap_max) / 360;
+
+ /* Set the Clock Phase */
+ if (tap_delay) {
+ u32 regval;
+
+ regval = sdhci_readl(host, SDHCI_ARASAN_ITAPDLY_REGISTER);
+ regval |= SDHCI_ITAPDLY_CHGWIN;
+ sdhci_writel(host, regval, SDHCI_ARASAN_ITAPDLY_REGISTER);
+ regval |= SDHCI_ITAPDLY_ENABLE;
+ sdhci_writel(host, regval, SDHCI_ARASAN_ITAPDLY_REGISTER);
+ regval |= tap_delay;
+ sdhci_writel(host, regval, SDHCI_ARASAN_ITAPDLY_REGISTER);
+ regval &= ~SDHCI_ITAPDLY_CHGWIN;
+ sdhci_writel(host, regval, SDHCI_ARASAN_ITAPDLY_REGISTER);
+ }
+
+ return ret;
+}
+
+static const struct clk_ops versal_sampleclk_ops = {
+ .recalc_rate = sdhci_arasan_sampleclk_recalc_rate,
+ .set_phase = sdhci_versal_sampleclk_set_phase,
+};
+
static void arasan_zynqmp_dll_reset(struct sdhci_host *host, u32 deviceid)
{
struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
@@ -965,6 +1126,16 @@ static void arasan_dt_parse_clk_phases(struct device *dev,
}
}

+ if (of_device_is_compatible(dev->of_node, "xlnx,versal-8.9a")) {
+ iclk_phase = (int [MMC_TIMING_MMC_HS400 + 1]) VERSAL_ICLK_PHASE;
+ oclk_phase = (int [MMC_TIMING_MMC_HS400 + 1]) VERSAL_OCLK_PHASE;
+
+ for (i = 0; i <= MMC_TIMING_MMC_HS400; i++) {
+ clk_data->clk_phase_in[i] = iclk_phase[i];
+ clk_data->clk_phase_out[i] = oclk_phase[i];
+ }
+ }
+
arasan_dt_read_clk_phase(dev, clk_data, MMC_TIMING_LEGACY,
"clk-phase-legacy");
arasan_dt_read_clk_phase(dev, clk_data, MMC_TIMING_MMC_HS,
@@ -1025,6 +1196,8 @@ sdhci_arasan_register_sdcardclk(struct sdhci_arasan_data *sdhci_arasan,
sdcardclk_init.flags = CLK_GET_RATE_NOCACHE;
if (of_device_is_compatible(np, "xlnx,zynqmp-8.9a"))
sdcardclk_init.ops = &zynqmp_sdcardclk_ops;
+ else if (of_device_is_compatible(np, "xlnx,versal-8.9a"))
+ sdcardclk_init.ops = &versal_sdcardclk_ops;
else
sdcardclk_init.ops = &arasan_sdcardclk_ops;

@@ -1077,6 +1250,8 @@ sdhci_arasan_register_sampleclk(struct sdhci_arasan_data *sdhci_arasan,
sampleclk_init.flags = CLK_GET_RATE_NOCACHE;
if (of_device_is_compatible(np, "xlnx,zynqmp-8.9a"))
sampleclk_init.ops = &zynqmp_sampleclk_ops;
+ else if (of_device_is_compatible(np, "xlnx,versal-8.9a"))
+ sampleclk_init.ops = &versal_sampleclk_ops;
else
sampleclk_init.ops = &arasan_sampleclk_ops;

--
2.17.1