This patch adds implementation for platform specific tuning in order to support
HS200 bus speed mode on Qualcomm SDHCI controller.

Signed-off-by: Asutosh Das <asuto...@codeaurora.org>
Signed-off-by: Venkat Gopalakrishnan <venk...@codeaurora.org>
Signed-off-by: Georgi Djakov <gdja...@mm-sol.com>
---
 drivers/mmc/host/sdhci-msm.c |  424 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 418 insertions(+), 6 deletions(-)

diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
index b4490a2..69f6887 100644
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c
@@ -18,6 +18,8 @@
 #include <linux/of_device.h>
 #include <linux/regulator/consumer.h>
 #include <linux/delay.h>
+#include <linux/mmc/mmc.h>
+#include <linux/slab.h>
 
 #include "sdhci-pltfm.h"
 
@@ -43,7 +45,45 @@
 #define CORE_PWRCTL_IO_FAIL    BIT(3)
 
 #define INT_MASK               0xf
+#define MAX_PHASES             16
+
+#define CORE_DLL_LOCK          BIT(7)
+#define CORE_DLL_EN            BIT(16)
+#define CORE_CDR_EN            BIT(17)
+#define CORE_CK_OUT_EN         BIT(18)
+#define CORE_CDR_EXT_EN                BIT(19)
+#define CORE_DLL_PDN           BIT(29)
+#define CORE_DLL_RST           BIT(30)
+#define CORE_DLL_CONFIG                0x100
+#define CORE_DLL_TEST_CTL      0x104
+#define CORE_DLL_STATUS                0x108
+
+#define CORE_VENDOR_SPEC       0x10c
+#define CORE_CLK_PWRSAVE       BIT(1)
+#define CORE_IO_PAD_PWR_SWITCH BIT(16)
+
+#define CDR_SELEXT_SHIFT       20
+#define CDR_SELEXT_MASK                (0xf << CDR_SELEXT_SHIFT)
+#define CMUX_SHIFT_PHASE_SHIFT 24
+#define CMUX_SHIFT_PHASE_MASK  (7 << CMUX_SHIFT_PHASE_SHIFT)
+
+static const u32 tuning_block_64[] = {
+       0x00ff0fff, 0xccc3ccff, 0xffcc3cc3, 0xeffefffe,
+       0xddffdfff, 0xfbfffbff, 0xff7fffbf, 0xefbdf777,
+       0xf0fff0ff, 0x3cccfc0f, 0xcfcc33cc, 0xeeffefff,
+       0xfdfffdff, 0xffbfffdf, 0xfff7ffbb, 0xde7b7ff7
+};
 
+static const u32 tuning_block_128[] = {
+       0xff00ffff, 0x0000ffff, 0xccccffff, 0xcccc33cc,
+       0xcc3333cc, 0xffffcccc, 0xffffeeff, 0xffeeeeff,
+       0xffddffff, 0xddddffff, 0xbbffffff, 0xbbffffff,
+       0xffffffbb, 0xffffff77, 0x77ff7777, 0xffeeddbb,
+       0x00ffffff, 0x00ffffff, 0xccffff00, 0xcc33cccc,
+       0x3333cccc, 0xffcccccc, 0xffeeffff, 0xeeeeffff,
+       0xddffffff, 0xddffffff, 0xffffffdd, 0xffffffbb,
+       0xffffbbbb, 0xffff77ff, 0xff7777ff, 0xeeddbb77
+};
 
 /* This structure keeps information per regulator */
 struct sdhci_msm_reg_data {
@@ -73,18 +113,390 @@ struct sdhci_msm_host {
        struct sdhci_pltfm_data sdhci_msm_pdata;
 };
 
-/* MSM platform specific tuning */
-int sdhci_msm_execute_tuning(struct sdhci_host *host, u32 opcode)
+/* Platform specific tuning */
+static inline int msm_dll_poll_ck_out_en(struct sdhci_host *host, u8 poll)
+{
+       u32 wait_cnt = 50;
+       u8 ck_out_en;
+       struct mmc_host *mmc = host->mmc;
+
+       /* Poll for CK_OUT_EN bit.  max. poll time = 50us */
+       ck_out_en = !!(readl_relaxed(host->ioaddr + CORE_DLL_CONFIG) &
+                       CORE_CK_OUT_EN);
+
+       while (ck_out_en != poll) {
+               if (--wait_cnt == 0) {
+                       dev_err(mmc_dev(mmc), "%s: CK_OUT_EN bit is not %d\n",
+                              mmc_hostname(mmc), poll);
+                       return -ETIMEDOUT;
+               }
+               udelay(1);
+
+               ck_out_en = !!(readl_relaxed(host->ioaddr + CORE_DLL_CONFIG) &
+                               CORE_CK_OUT_EN);
+       }
+
+       return 0;
+}
+
+static int msm_config_cm_dll_phase(struct sdhci_host *host, u8 phase)
+{
+       int rc;
+       static const u8 grey_coded_phase_table[] = {
+               0x0, 0x1, 0x3, 0x2, 0x6, 0x7, 0x5, 0x4,
+               0xc, 0xd, 0xf, 0xe, 0xa, 0xb, 0x9, 0x8
+       };
+       unsigned long flags;
+       u32 config;
+       struct mmc_host *mmc = host->mmc;
+
+       spin_lock_irqsave(&host->lock, flags);
+
+       config = readl_relaxed(host->ioaddr + CORE_DLL_CONFIG);
+       config &= ~(CORE_CDR_EN | CORE_CK_OUT_EN);
+       config |= (CORE_CDR_EXT_EN | CORE_DLL_EN);
+       writel_relaxed(config, host->ioaddr + CORE_DLL_CONFIG);
+
+       /* Wait until CK_OUT_EN bit of DLL_CONFIG register becomes '0' */
+       rc = msm_dll_poll_ck_out_en(host, 0);
+       if (rc)
+               goto err_out;
+
+       /*
+        * Write the selected DLL clock output phase (0 ... 15)
+        * to CDR_SELEXT bit field of DLL_CONFIG register.
+        */
+       config = readl_relaxed(host->ioaddr + CORE_DLL_CONFIG);
+       config &= ~CDR_SELEXT_MASK;
+       config |= grey_coded_phase_table[phase] << CDR_SELEXT_SHIFT;
+       writel_relaxed(config, host->ioaddr + CORE_DLL_CONFIG);
+
+       /* Set CK_OUT_EN bit of DLL_CONFIG register to 1. */
+       writel_relaxed((readl_relaxed(host->ioaddr + CORE_DLL_CONFIG)
+                       | CORE_CK_OUT_EN), host->ioaddr + CORE_DLL_CONFIG);
+
+       /* Wait until CK_OUT_EN bit of DLL_CONFIG register becomes '1' */
+       rc = msm_dll_poll_ck_out_en(host, 1);
+       if (rc)
+               goto err_out;
+
+       config = readl_relaxed(host->ioaddr + CORE_DLL_CONFIG);
+       config |= CORE_CDR_EN;
+       config &= ~CORE_CDR_EXT_EN;
+       writel_relaxed(config, host->ioaddr + CORE_DLL_CONFIG);
+       goto out;
+
+err_out:
+       dev_err(mmc_dev(mmc), "%s: Failed to set DLL phase: %d\n",
+              mmc_hostname(mmc), phase);
+out:
+       spin_unlock_irqrestore(&host->lock, flags);
+       return rc;
+}
+
+/*
+ * Find out the greatest range of consecuitive selected
+ * DLL clock output phases that can be used as sampling
+ * setting for SD3.0 UHS-I card read operation (in SDR104
+ * timing mode) or for eMMC4.5 card read operation (in HS200
+ * timing mode).
+ * Select the 3/4 of the range and configure the DLL with the
+ * selected DLL clock output phase.
+ */
+
+static int msm_find_most_appropriate_phase(struct sdhci_host *host,
+                                          u8 *phase_table, u8 total_phases)
+{
+       int ret;
+       u8 ranges[MAX_PHASES][MAX_PHASES] = { {0}, {0} };
+       u8 phases_per_row[MAX_PHASES] = { 0 };
+       int row_index = 0, col_index = 0, selected_row_index = 0, curr_max = 0;
+       int i, cnt, phase_0_raw_index = 0, phase_15_raw_index = 0;
+       bool phase_0_found = false, phase_15_found = false;
+       struct mmc_host *mmc = host->mmc;
+
+       if (!total_phases || (total_phases > MAX_PHASES)) {
+               dev_err(mmc_dev(mmc), "%s: Invalid argument: total_phases=%d\n",
+                      mmc_hostname(mmc), total_phases);
+               return -EINVAL;
+       }
+
+       for (cnt = 0; cnt < total_phases; cnt++) {
+               ranges[row_index][col_index] = phase_table[cnt];
+               phases_per_row[row_index] += 1;
+               col_index++;
+
+               if ((cnt + 1) == total_phases) {
+                       continue;
+               /* check if next phase in phase_table is consecutive or not */
+               } else if ((phase_table[cnt] + 1) != phase_table[cnt + 1]) {
+                       row_index++;
+                       col_index = 0;
+               }
+       }
+
+       if (row_index >= MAX_PHASES)
+               return -EINVAL;
+
+       /* Check if phase-0 is present in first valid window? */
+       if (!ranges[0][0]) {
+               phase_0_found = true;
+               phase_0_raw_index = 0;
+               /* Check if cycle exist between 2 valid windows */
+               for (cnt = 1; cnt <= row_index; cnt++) {
+                       if (phases_per_row[cnt]) {
+                               for (i = 0; i < phases_per_row[cnt]; i++) {
+                                       if (ranges[cnt][i] == 15) {
+                                               phase_15_found = true;
+                                               phase_15_raw_index = cnt;
+                                               break;
+                                       }
+                               }
+                       }
+               }
+       }
+
+       /* If 2 valid windows form cycle then merge them as single window */
+       if (phase_0_found && phase_15_found) {
+               /* number of phases in raw where phase 0 is present */
+               u8 phases_0 = phases_per_row[phase_0_raw_index];
+               /* number of phases in raw where phase 15 is present */
+               u8 phases_15 = phases_per_row[phase_15_raw_index];
+
+               if (phases_0 + phases_15 >= MAX_PHASES)
+                       /*
+                        * If there are more than 1 phase windows then total
+                        * number of phases in both the windows should not be
+                        * more than or equal to MAX_PHASES.
+                        */
+                       return -EINVAL;
+
+               /* Merge 2 cyclic windows */
+               i = phases_15;
+               for (cnt = 0; cnt < phases_0; cnt++) {
+                       ranges[phase_15_raw_index][i] =
+                           ranges[phase_0_raw_index][cnt];
+                       if (++i >= MAX_PHASES)
+                               break;
+               }
+
+               phases_per_row[phase_0_raw_index] = 0;
+               phases_per_row[phase_15_raw_index] = phases_15 + phases_0;
+       }
+
+       for (cnt = 0; cnt <= row_index; cnt++) {
+               if (phases_per_row[cnt] > curr_max) {
+                       curr_max = phases_per_row[cnt];
+                       selected_row_index = cnt;
+               }
+       }
+
+       i = (curr_max * 3) / 4;
+       if (i)
+               i--;
+
+       ret = ranges[selected_row_index][i];
+
+       if (ret >= MAX_PHASES) {
+               ret = -EINVAL;
+               dev_err(mmc_dev(mmc), "%s: Invalid phase selected=%d\n",
+                      mmc_hostname(mmc), ret);
+       }
+
+       return ret;
+}
+
+static inline void msm_cm_dll_set_freq(struct sdhci_host *host)
+{
+       u32 mclk_freq = 0, config;
+
+       /* Program the MCLK value to MCLK_FREQ bit field */
+       if (host->clock <= 112000000)
+               mclk_freq = 0;
+       else if (host->clock <= 125000000)
+               mclk_freq = 1;
+       else if (host->clock <= 137000000)
+               mclk_freq = 2;
+       else if (host->clock <= 150000000)
+               mclk_freq = 3;
+       else if (host->clock <= 162000000)
+               mclk_freq = 4;
+       else if (host->clock <= 175000000)
+               mclk_freq = 5;
+       else if (host->clock <= 187000000)
+               mclk_freq = 6;
+       else if (host->clock <= 200000000)
+               mclk_freq = 7;
+
+       config = readl_relaxed(host->ioaddr + CORE_DLL_CONFIG);
+       config &= ~CMUX_SHIFT_PHASE_MASK;
+       config |= mclk_freq << CMUX_SHIFT_PHASE_SHIFT;
+       writel_relaxed(config, host->ioaddr + CORE_DLL_CONFIG);
+}
+
+/* Initialize the DLL (Programmable Delay Line) */
+static int msm_init_cm_dll(struct sdhci_host *host)
 {
+       struct mmc_host *mmc = host->mmc;
+       int wait_cnt = 50;
+       unsigned long flags;
+
+       spin_lock_irqsave(&host->lock, flags);
+
        /*
-        * Tuning is required for SDR104, HS200 and HS400 cards and if the clock
-        * frequency greater than 100MHz in those modes. The standard tuning
-        * procedure should not be executed, but a custom implementation will be
-        * added here instead.
+        * Make sure that clock is always enabled when DLL
+        * tuning is in progress. Keeping PWRSAVE ON may
+        * turn off the clock.
         */
+       writel_relaxed((readl_relaxed(host->ioaddr + CORE_VENDOR_SPEC)
+                       & ~CORE_CLK_PWRSAVE), host->ioaddr + CORE_VENDOR_SPEC);
+
+       /* Write 1 to DLL_RST bit of DLL_CONFIG register */
+       writel_relaxed((readl_relaxed(host->ioaddr + CORE_DLL_CONFIG)
+                       | CORE_DLL_RST), host->ioaddr + CORE_DLL_CONFIG);
+
+       /* Write 1 to DLL_PDN bit of DLL_CONFIG register */
+       writel_relaxed((readl_relaxed(host->ioaddr + CORE_DLL_CONFIG)
+                       | CORE_DLL_PDN), host->ioaddr + CORE_DLL_CONFIG);
+       msm_cm_dll_set_freq(host);
+
+       /* Write 0 to DLL_RST bit of DLL_CONFIG register */
+       writel_relaxed((readl_relaxed(host->ioaddr + CORE_DLL_CONFIG)
+                       & ~CORE_DLL_RST), host->ioaddr + CORE_DLL_CONFIG);
+
+       /* Write 0 to DLL_PDN bit of DLL_CONFIG register */
+       writel_relaxed((readl_relaxed(host->ioaddr + CORE_DLL_CONFIG)
+                       & ~CORE_DLL_PDN), host->ioaddr + CORE_DLL_CONFIG);
+
+       /* Set DLL_EN bit to 1. */
+       writel_relaxed((readl_relaxed(host->ioaddr + CORE_DLL_CONFIG)
+                       | CORE_DLL_EN), host->ioaddr + CORE_DLL_CONFIG);
+
+       /* Set CK_OUT_EN bit to 1. */
+       writel_relaxed((readl_relaxed(host->ioaddr + CORE_DLL_CONFIG)
+                       | CORE_CK_OUT_EN), host->ioaddr + CORE_DLL_CONFIG);
+
+       /* Wait until DLL_LOCK bit of DLL_STATUS register becomes '1' */
+       while (!(readl_relaxed(host->ioaddr + CORE_DLL_STATUS) &
+                CORE_DLL_LOCK)) {
+               /* max. wait for 50us sec for LOCK bit to be set */
+               if (--wait_cnt == 0) {
+                       dev_err(mmc_dev(mmc), "%s: DLL failed to LOCK\n",
+                              mmc_hostname(mmc));
+                       spin_unlock_irqrestore(&host->lock, flags);
+                       return -ETIMEDOUT;
+               }
+               udelay(1);
+       }
+
+       spin_unlock_irqrestore(&host->lock, flags);
        return 0;
 }
 
+int sdhci_msm_execute_tuning(struct sdhci_host *host, u32 opcode)
+{
+       int tuning_seq_cnt = 3;
+       u8 phase, *data_buf, tuned_phases[16], tuned_phase_cnt = 0;
+       const u32 *tuning_block_pattern = tuning_block_64;
+       int size = sizeof(tuning_block_64);     /* Pattern size in bytes */
+       int rc;
+       struct mmc_host *mmc = host->mmc;
+       struct mmc_ios ios = host->mmc->ios;
+
+       /*
+        * Tuning is required for SDR104, HS200 and HS400 cards and
+        * if clock frequency is greater than 100MHz in these modes.
+        */
+       if (host->clock <= 100 * 1000 * 1000 ||
+           !((ios.timing == MMC_TIMING_MMC_HS200) ||
+             (ios.timing == MMC_TIMING_UHS_SDR104)))
+               return 0;
+
+       if ((opcode == MMC_SEND_TUNING_BLOCK_HS200) &&
+           (mmc->ios.bus_width == MMC_BUS_WIDTH_8)) {
+               tuning_block_pattern = tuning_block_128;
+               size = sizeof(tuning_block_128);
+       }
+
+       data_buf = kmalloc(size, GFP_KERNEL);
+       if (!data_buf)
+               return -ENOMEM;
+
+retry:
+       /* First of all reset the tuning block */
+       rc = msm_init_cm_dll(host);
+       if (rc)
+               goto out;
+
+       phase = 0;
+       do {
+               struct mmc_command cmd = { 0 };
+               struct mmc_data data = { 0 };
+               struct mmc_request mrq = {
+                       .cmd = &cmd,
+                       .data = &data
+               };
+               struct scatterlist sg;
+
+               /* Set the phase in delay line hw block */
+               rc = msm_config_cm_dll_phase(host, phase);
+               if (rc)
+                       goto out;
+
+               cmd.opcode = opcode;
+               cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;
+
+               data.blksz = size;
+               data.blocks = 1;
+               data.flags = MMC_DATA_READ;
+               data.timeout_ns = NSEC_PER_SEC; /* 1 second */
+
+               data.sg = &sg;
+               data.sg_len = 1;
+               sg_init_one(&sg, data_buf, sizeof(data_buf));
+               memset(data_buf, 0, sizeof(data_buf));
+               mmc_wait_for_req(mmc, &mrq);
+
+               if (!cmd.error && !data.error &&
+                   !memcmp(data_buf, tuning_block_pattern, sizeof(data_buf))) {
+                       /* Tuning is successful at this tuning point */
+                       tuned_phases[tuned_phase_cnt++] = phase;
+                       dev_dbg(mmc_dev(mmc), "%s: Found good phase = %d\n",
+                                mmc_hostname(mmc), phase);
+               }
+       } while (++phase < ARRAY_SIZE(tuned_phases));
+
+       if (tuned_phase_cnt) {
+               rc = msm_find_most_appropriate_phase(host, tuned_phases,
+                                                    tuned_phase_cnt);
+               if (rc < 0)
+                       goto out;
+               else
+                       phase = rc;
+
+               /*
+                * Finally set the selected phase in delay
+                * line hw block.
+                */
+               rc = msm_config_cm_dll_phase(host, phase);
+               if (rc)
+                       goto out;
+               dev_dbg(mmc_dev(mmc), "%s: Setting the tuning phase to %d\n",
+                        mmc_hostname(mmc), phase);
+       } else {
+               if (--tuning_seq_cnt)
+                       goto retry;
+               /* Tuning failed */
+               dev_dbg(mmc_dev(mmc), "%s: No tuning point found\n",
+                      mmc_hostname(mmc));
+               rc = -EIO;
+       }
+
+out:
+       kfree(data_buf);
+       return rc;
+}
+
 #define MAX_PROP_SIZE 32
 static int sdhci_msm_dt_parse_vreg_info(struct device *dev,
                        struct sdhci_msm_reg_data *vreg, const char *vreg_name)
-- 
1.7.9.5

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