From: Balaji T K <balaj...@ti.com>

MMC tuning procedure is required to support SD card
UHS1-SDR104 mode and EMMC HS200 mode.

The tuning function omap_execute_tuning() will only
be called by the MMC/SD core if the corresponding
speed modes are supported by the OMAP silicon which
is set in the mmc host "caps" field.

Signed-off-by: Balaji T K <balaj...@ti.com>
Signed-off-by: Viswanath Puttagunta <vi...@ti.com>
Signed-off-by: Sourav Poddar <sourav.pod...@ti.com>
[kis...@ti.com : cleanup the tuning sequence]
Signed-off-by: Kishon Vijay Abraham I <kis...@ti.com>
---
 drivers/mmc/host/omap_hsmmc.c |  234 ++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 232 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
index c042b91..43485c3 100644
--- a/drivers/mmc/host/omap_hsmmc.c
+++ b/drivers/mmc/host/omap_hsmmc.c
@@ -18,6 +18,7 @@
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
+#include <linux/slab.h>
 #include <linux/debugfs.h>
 #include <linux/dmaengine.h>
 #include <linux/seq_file.h>
@@ -49,6 +50,7 @@
 /* OMAP HSMMC Host Controller Registers */
 #define OMAP_HSMMC_SYSSTATUS   0x0014
 #define OMAP_HSMMC_CON         0x002C
+#define OMAP_HSMMC_DLL         0x0034
 #define OMAP_HSMMC_SDMASA      0x0100
 #define OMAP_HSMMC_BLK         0x0104
 #define OMAP_HSMMC_ARG         0x0108
@@ -66,6 +68,7 @@
 #define OMAP_HSMMC_ISE         0x0138
 #define OMAP_HSMMC_AC12                0x013C
 #define OMAP_HSMMC_CAPA                0x0140
+#define OMAP_HSMMC_CAPA2       0x0144
 
 #define VS18                   (1 << 26)
 #define VS30                   (1 << 25)
@@ -114,6 +117,7 @@
 
 /* AC12 */
 #define AC12_V1V8_SIGEN                (1 << 19)
+#define AC12_SCLK_SEL          (1 << 23)
 #define AC12_UHSMC_MASK                (7 << 16)
 #define AC12_UHSMC_SDR12       (0 << 16)
 #define AC12_UHSMC_SDR25       (1 << 16)
@@ -122,6 +126,18 @@
 #define AC12_UHSMC_DDR50       (4 << 16)
 #define AC12_UHSMC_RES         (0x7 << 16)
 
+/* DLL */
+#define DLL_SWT                        (1 << 20)
+#define DLL_FORCE_SR_C_SHIFT   13
+#define DLL_FORCE_SR_C_MASK    0x7f
+#define DLL_FORCE_VALUE                (1 << 12)
+#define DLL_CALIB              (1 << 1)
+
+#define MAX_PHASE_DELAY                0x7c
+
+/* CAPA2 */
+#define CAPA2_TSDR50           (1 << 13)
+
 /* Interrupt masks for IE and ISE register */
 #define CC_EN                  (1 << 0)
 #define TC_EN                  (1 << 1)
@@ -202,6 +218,7 @@ struct omap_hsmmc_host {
        int                     vqmmc_enabled;
        resource_size_t         mapbase;
        spinlock_t              irq_lock; /* Prevent races with irq handler */
+       struct completion       buf_ready;
        unsigned int            dma_len;
        unsigned int            dma_sg_idx;
        unsigned char           bus_mode;
@@ -229,6 +246,9 @@ struct omap_hsmmc_host {
        struct omap_hsmmc_next  next_data;
        struct  omap_hsmmc_platform_data        *pdata;
 
+       u32                     *tuning_data;
+       int                     tuning_size;
+
        /* return MMC cover switch state, can be NULL if not supported.
         *
         * possible return values:
@@ -245,8 +265,39 @@ struct omap_mmc_of_data {
        u8 controller_flags;
 };
 
+static const u8 ref_tuning_4bits[] = {
+       0xff, 0x0f, 0xff, 0x00, 0xff, 0xcc, 0xc3, 0xcc,
+       0xc3, 0x3c, 0xcc, 0xff, 0xfe, 0xff, 0xfe, 0xef,
+       0xff, 0xdf, 0xff, 0xdd, 0xff, 0xfb, 0xff, 0xfb,
+       0xbf, 0xff, 0x7f, 0xff, 0x77, 0xf7, 0xbd, 0xef,
+       0xff, 0xf0, 0xff, 0xf0, 0x0f, 0xfc, 0xcc, 0x3c,
+       0xcc, 0x33, 0xcc, 0xcf, 0xff, 0xef, 0xff, 0xee,
+       0xff, 0xfd, 0xff, 0xfd, 0xdf, 0xff, 0xbf, 0xff,
+       0xbb, 0xff, 0xf7, 0xff, 0xf7, 0x7f, 0x7b, 0xde,
+};
+
+static const u8 ref_tuning_8bits[] = {
+       0xff, 0xff, 0x00, 0xff, 0xff, 0xff, 0x00, 0x00,
+       0xff, 0xff, 0xcc, 0xcc, 0xcc, 0x33, 0xcc, 0xcc,
+       0xcc, 0x33, 0x33, 0xcc, 0xcc, 0xcc, 0xff, 0xff,
+       0xff, 0xee, 0xff, 0xff, 0xff, 0xee, 0xee, 0xff,
+       0xff, 0xff, 0xdd, 0xff, 0xff, 0xff, 0xdd, 0xdd,
+       0xff, 0xff, 0xff, 0xbb, 0xff, 0xff, 0xff, 0xbb,
+       0xbb, 0xff, 0xff, 0xff, 0x77, 0xff, 0xff, 0xff,
+       0x77, 0x77, 0xff, 0x77, 0xbb, 0xdd, 0xee, 0xff,
+       0xff, 0xff, 0xff, 0x00, 0xff, 0xff, 0xff, 0x00,
+       0x00, 0xff, 0xff, 0xcc, 0xcc, 0xcc, 0x33, 0xcc,
+       0xcc, 0xcc, 0x33, 0x33, 0xcc, 0xcc, 0xcc, 0xff,
+       0xff, 0xff, 0xee, 0xff, 0xff, 0xff, 0xee, 0xee,
+       0xff, 0xff, 0xff, 0xdd, 0xff, 0xff, 0xff, 0xdd,
+       0xdd, 0xff, 0xff, 0xff, 0xbb, 0xff, 0xff, 0xff,
+       0xbb, 0xbb, 0xff, 0xff, 0xff, 0x77, 0xff, 0xff,
+       0xff, 0x77, 0x77, 0xff, 0x77, 0xbb, 0xdd, 0xee,
+};
+
 static void omap_hsmmc_start_dma_transfer(struct omap_hsmmc_host *host);
 static void omap_hsmmc_conf_bus_power(struct omap_hsmmc_host *host, int iov);
+static void omap_hsmmc_disable_tuning(struct omap_hsmmc_host *host);
 
 static int omap_hsmmc_card_detect(struct device *dev)
 {
@@ -609,8 +660,12 @@ static void omap_hsmmc_enable_irq(struct omap_hsmmc_host 
*host,
 {
        u32 irq_mask = INT_EN_MASK;
        unsigned long flags;
+       bool is_tuning;
 
-       if (host->use_dma)
+       is_tuning = (cmd->opcode == MMC_SEND_TUNING_BLOCK) ||
+                   (cmd->opcode == MMC_SEND_TUNING_BLOCK_HS200);
+
+       if (!is_tuning && host->use_dma)
                irq_mask &= ~(BRR_EN | BWR_EN);
 
        /* Disable timeout for erases */
@@ -956,7 +1011,11 @@ omap_hsmmc_start_command(struct omap_hsmmc_host *host, 
struct mmc_command *cmd,
                        cmdreg &= ~(DDIR);
        }
 
-       if (host->use_dma)
+       /* Tuning command is special. Data Present Select should be set */
+       if ((cmd->opcode == MMC_SEND_TUNING_BLOCK) ||
+           (cmd->opcode == MMC_SEND_TUNING_BLOCK_HS200))
+               cmdreg |= DP_SELECT | DDIR;
+       else if (host->use_dma)
                cmdreg |= DMAE;
 
        host->req_in_progress = 1;
@@ -1187,6 +1246,7 @@ static void omap_hsmmc_do_irq(struct omap_hsmmc_host 
*host, int status)
        struct mmc_data *data;
        int end_cmd = 0, end_trans = 0;
        int error = 0;
+       int i;
 
        data = host->data;
        dev_vdbg(mmc_dev(host->mmc), "IRQ Status is %x\n", status);
@@ -1222,6 +1282,13 @@ static void omap_hsmmc_do_irq(struct omap_hsmmc_host 
*host, int status)
                }
        }
 
+       if (status & BRR_EN) {
+               for (i = 0; i < host->tuning_size / 4; i++)
+                       host->tuning_data[i] =
+                               OMAP_HSMMC_READ(host->base, DATA);
+               complete(&host->buf_ready);
+       }
+
        OMAP_HSMMC_WRITE(host->base, STAT, status);
        if (end_cmd || ((status & CC_EN) && host->cmd))
                omap_hsmmc_cmd_done(host, host->cmd);
@@ -1721,6 +1788,7 @@ static void omap_hsmmc_set_ios(struct mmc_host *mmc, 
struct mmc_ios *ios)
        if (ios->power_mode != host->power_mode) {
                switch (ios->power_mode) {
                case MMC_POWER_OFF:
+                       omap_hsmmc_disable_tuning(host);
                        mmc_pdata(host)->set_power(host->dev, 0, 0);
                        break;
                case MMC_POWER_UP:
@@ -2035,6 +2103,166 @@ static int omap_hsmmc_card_busy(struct mmc_host *mmc)
        return ret;
 }
 
+static inline void omap_hsmmc_set_dll(struct omap_hsmmc_host *host, int count)
+{
+       int i;
+       u32 dll;
+
+       dll = OMAP_HSMMC_READ(host->base, DLL);
+       dll |= DLL_FORCE_VALUE;
+       dll &= ~(DLL_FORCE_SR_C_MASK << DLL_FORCE_SR_C_SHIFT);
+       dll |= (count << DLL_FORCE_SR_C_SHIFT);
+       OMAP_HSMMC_WRITE(host->base, DLL, dll);
+
+       dll |= DLL_CALIB;
+       OMAP_HSMMC_WRITE(host->base, DLL, dll);
+       for (i = 0; i < 1000; i++) {
+               if (OMAP_HSMMC_READ(host->base, DLL) & DLL_CALIB)
+                       break;
+       }
+       dll &= ~DLL_CALIB;
+       OMAP_HSMMC_WRITE(host->base, DLL, dll);
+}
+
+static void omap_hsmmc_disable_tuning(struct omap_hsmmc_host *host)
+{
+       int val;
+
+       val = OMAP_HSMMC_READ(host->base, AC12);
+       val &= ~(AC12_SCLK_SEL);
+       OMAP_HSMMC_WRITE(host->base, AC12, val);
+
+       val = OMAP_HSMMC_READ(host->base, DLL);
+       val &= ~(DLL_FORCE_VALUE | DLL_SWT);
+       OMAP_HSMMC_WRITE(host->base, DLL, val);
+}
+
+static int omap_hsmmc_execute_tuning(struct mmc_host *mmc, u32 opcode)
+{
+       u32 val;
+       u8 cur_match, prev_match = 0;
+       int ret;
+       u32 phase_delay = 0;
+       u32 start_window = 0, max_window = 0;
+       u32 length = 0, max_len = 0;
+       const u8 *tuning_ref;
+       struct mmc_ios *ios = &mmc->ios;
+       struct omap_hsmmc_host *host;
+       struct mmc_command cmd = {0};
+       struct mmc_request mrq = {NULL};
+
+       /* clock tuning is not needed for upto 52MHz */
+       if (ios->clock <= OMAP_MMC_MAX_CLOCK)
+               return 0;
+
+       host = mmc_priv(mmc);
+
+       val = OMAP_HSMMC_READ(host->base, CAPA2);
+       if (ios->timing == MMC_TIMING_UHS_SDR50 && !(val & CAPA2_TSDR50))
+               return 0;
+
+       switch (ios->bus_width) {
+       case MMC_BUS_WIDTH_8:
+               tuning_ref = ref_tuning_8bits;
+               host->tuning_size = sizeof(ref_tuning_8bits);
+               break;
+       case MMC_BUS_WIDTH_4:
+               tuning_ref = ref_tuning_4bits;
+               host->tuning_size = sizeof(ref_tuning_4bits);
+               break;
+       default:
+               return -EINVAL;
+       }
+
+       host->tuning_data = kzalloc(host->tuning_size, GFP_KERNEL);
+       if (!host->tuning_data)
+               return -ENOMEM;
+
+       val = OMAP_HSMMC_READ(host->base, DLL);
+       val |= DLL_SWT;
+       OMAP_HSMMC_WRITE(host->base, DLL, val);
+
+       while (phase_delay <= MAX_PHASE_DELAY) {
+               omap_hsmmc_set_dll(host, phase_delay);
+
+               cmd.opcode = opcode;
+               cmd.arg = 0;
+               cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;
+               cmd.retries = 0;
+               cmd.data = NULL;
+               cmd.error = 0;
+
+               mrq.cmd = &cmd;
+               host->mrq = &mrq;
+               OMAP_HSMMC_WRITE(host->base, BLK, host->tuning_size);
+               set_data_timeout(host, 150000000, 0);
+               omap_hsmmc_start_command(host, &cmd, NULL);
+               host->cmd = NULL;
+               host->mrq = NULL;
+
+               ret = wait_for_completion_timeout(&host->buf_ready,
+                                                 msecs_to_jiffies(5000));
+               if (ret == 0) {
+                       dev_err(mmc_dev(host->mmc), "Tuning BRR timeout");
+                       ret = -ETIMEDOUT;
+                       goto tuning_error;
+               }
+
+               host->req_in_progress = false;
+
+               cur_match = !memcmp(host->tuning_data, tuning_ref,
+                                   host->tuning_size);
+               if (cur_match) {
+                       if (prev_match) {
+                               length++;
+                       } else {
+                               start_window = phase_delay;
+                               length = 1;
+                       }
+               }
+
+               if (length > max_len) {
+                       max_window = start_window;
+                       max_len = length;
+               }
+
+               prev_match = cur_match;
+               phase_delay += 4;
+       }
+
+       if (!max_len) {
+               dev_err(mmc_dev(host->mmc), "Unable to find match\n");
+               ret = -EIO;
+               goto tuning_error;
+       }
+
+       val = OMAP_HSMMC_READ(host->base, AC12);
+       if (!(val & AC12_SCLK_SEL)) {
+               ret = -EIO;
+               goto tuning_error;
+       }
+
+       phase_delay = max_window + 4 * (max_len >> 1);
+       omap_hsmmc_set_dll(host, phase_delay);
+
+       omap_hsmmc_reset_controller_fsm(host, SRD);
+       omap_hsmmc_reset_controller_fsm(host, SRC);
+
+       kfree(host->tuning_data);
+       return 0;
+
+tuning_error:
+       dev_err(mmc_dev(host->mmc),
+               "Tuning failed. Using fixed sampling clock\n");
+
+       omap_hsmmc_disable_tuning(host);
+       omap_hsmmc_reset_controller_fsm(host, SRD);
+       omap_hsmmc_reset_controller_fsm(host, SRC);
+
+       kfree(host->tuning_data);
+       return ret;
+}
+
 static struct mmc_host_ops omap_hsmmc_ops = {
        .post_req = omap_hsmmc_post_req,
        .pre_req = omap_hsmmc_pre_req,
@@ -2046,6 +2274,7 @@ static struct mmc_host_ops omap_hsmmc_ops = {
        .enable_sdio_irq = omap_hsmmc_enable_sdio_irq,
        .start_signal_voltage_switch = omap_hsmmc_start_signal_voltage_switch,
        .card_busy = omap_hsmmc_card_busy,
+       .execute_tuning = omap_hsmmc_execute_tuning,
 };
 
 #ifdef CONFIG_DEBUG_FS
@@ -2275,6 +2504,7 @@ static int omap_hsmmc_probe(struct platform_device *pdev)
                mmc->f_max = OMAP_MMC_MAX_CLOCK;
 
        spin_lock_init(&host->irq_lock);
+       init_completion(&host->buf_ready);
 
        host->fclk = devm_clk_get(&pdev->dev, "fck");
        if (IS_ERR(host->fclk)) {
-- 
1.7.9.5

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