[PATCH v2 07/11] mmc: host: omap_hsmmc: add tuning support

From: Kishon Vijay Abraham I
Date: Tue Aug 25 2015 - 05:08:12 EST

From: Balaji T K <balajitk@xxxxxx>

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 <balajitk@xxxxxx>
Signed-off-by: Viswanath Puttagunta <vishp@xxxxxx>
Signed-off-by: Sourav Poddar <sourav.poddar@xxxxxx>
[kishon@xxxxxx : cleanup the tuning sequence]
Signed-off-by: Kishon Vijay Abraham I <kishon@xxxxxx>
---
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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