Host Controller v3.00 can support retuning modes 1,2 or 3 depending on
the bits 46-47 of the Capabilities register. Also, the timer count for
retuning is indicated by bits 40-43 of the same register. We initialize
timer_list for retuning the first time we execute tuning procedure. This
condition is indicated by SDHCI_NEEDS_RETUNING not being set. Since
retuning mode 1 sets a limit of 4MB on the maximum data length, we set
max_blk_count appropriately. Once the tuning timer expires, we set
SDHCI_NEEDS_RETUNING flag, and if the flag is set, we execute tuning
procedure before sending the next command. We need to restore mmc_request
structure after executing retuning procedure since host->mrq is used
inside the procedure to send CMD19. We also disable and re-enable this
flag during suspend and resume respectively, as per the spec v3.00.
Signed-off-by: Arindam Nath <arindam.nath@xxxxxxx>
---
drivers/mmc/host/sdhci.c | 113 ++++++++++++++++++++++++++++++++++++++++++++-
drivers/mmc/host/sdhci.h | 6 ++-
include/linux/mmc/sdhci.h | 6 ++
3 files changed, 122 insertions(+), 3 deletions(-)
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index d11e577..37fdbcb 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -47,6 +47,8 @@ static void sdhci_finish_data(struct sdhci_host *);
static void sdhci_send_command(struct sdhci_host *, struct mmc_command *);
static void sdhci_finish_command(struct sdhci_host *);
+static int sdhci_execute_tuning(struct mmc_host *mmc);
+static void sdhci_tuning_timer(unsigned long data);
static void sdhci_dumpregs(struct sdhci_host *host)
{
@@ -1249,8 +1251,28 @@ static void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
if (!present || host->flags & SDHCI_DEVICE_DEAD) {
host->mrq->cmd->error = -ENOMEDIUM;
tasklet_schedule(&host->finish_tasklet);
- } else
+ } else {
+ u32 present_state;
+
+ present_state = sdhci_readl(host, SDHCI_PRESENT_STATE);
+ /*
+ * Check if the re-tuning timer has already expired and there
+ * is no on-going data transfer. If so, we need to execute
+ * tuning procedure before sending command.
+ */
+ if ((host->flags & SDHCI_NEEDS_RETUNING) &&
+ !(present_state & (SDHCI_DOING_WRITE |
+ SDHCI_DOING_READ))) {
+ spin_unlock_irqrestore(&host->lock, flags);
+ sdhci_execute_tuning(mmc);
+ spin_lock_irqsave(&host->lock, flags);
+
+ /* Restore original mmc_request structure */
+ host->mrq = mrq;
+ }
+
sdhci_send_command(host, mrq->cmd);
+ }
mmiowb();
spin_unlock_irqrestore(&host->lock, flags);
@@ -1682,6 +1704,37 @@ static int sdhci_execute_tuning(struct mmc_host *mmc)
}
out:
+ /*
+ * If this is the very first time we are here, we start the retuning
+ * timer. Since only during the first time, SDHCI_NEEDS_RETUNING
+ * flag won't be set, we check this condition before actually starting
+ * the timer.
+ */
+ if (!(host->flags & SDHCI_NEEDS_RETUNING) && host->tuning_count &&
+ (host->tuning_mode == SDHCI_TUNING_MODE_1)) {
+ mod_timer(&host->tuning_timer, jiffies + host->tuning_count *
+ HZ);
+ /* Tuning mode 1 limits the maximum data length to 4MB */
+ mmc->max_blk_count = (4 * 1024 * 1024) / mmc->max_blk_size;
+ } else {
+ host->flags &= ~SDHCI_NEEDS_RETUNING;
+ /* Reload the new initial value for timer */
+ if (host->tuning_mode == SDHCI_TUNING_MODE_1)
+ mod_timer(&host->tuning_timer, jiffies +
+ host->tuning_count * HZ);
+ }
+
+ /*
+ * In case tuning fails, host controllers which support re-tuning can
+ * try tuning again at a later time, when the re-tuning timer expires.
+ * So for these controllers, we return 0. Since there might be other
+ * controllers who do not have this capability, we return error for
+ * them.
+ */
+ if (err && host->tuning_count &&
+ (host->tuning_mode == SDHCI_TUNING_MODE_1))
+ err = 0;
+
sdhci_mask_irqs(host, SDHCI_INT_DATA_AVAIL);
spin_unlock(&host->lock);
enable_irq(host->irq);
@@ -1777,6 +1830,10 @@ static void sdhci_tasklet_finish(unsigned long param)
del_timer(&host->timer);
+ if (host->version >= SDHCI_SPEC_300)
+ del_timer(&host->tuning_timer);
+
+
mrq = host->mrq;
/*
@@ -1852,6 +1909,20 @@ static void sdhci_timeout_timer(unsigned long data)
spin_unlock_irqrestore(&host->lock, flags);
}
+static void sdhci_tuning_timer(unsigned long data)
+{
+ struct sdhci_host *host;
+ unsigned long flags;
+
+ host = (struct sdhci_host *)data;
+
+ spin_lock_irqsave(&host->lock, flags);
+
+ host->flags |= SDHCI_NEEDS_RETUNING;
+
+ spin_unlock_irqrestore(&host->lock, flags);
+}
+
/*****************************************************************************\
* *
* Interrupt handling *
@@ -2128,6 +2199,15 @@ int sdhci_suspend_host(struct sdhci_host *host, pm_message_t state)
sdhci_disable_card_detection(host);
+ /* Disable tuning since we are suspending */
+ if ((host->version >= SDHCI_SPEC_300) &&
+ host->tuning_count &&
+ (host->tuning_mode == SDHCI_TUNING_MODE_1)) {
+ host->flags &= ~SDHCI_NEEDS_RETUNING;
+ mod_timer(&host->tuning_timer, jiffies +
+ host->tuning_count * HZ);
+ }
+
ret = mmc_suspend_host(host->mmc);
if (ret)
return ret;
@@ -2169,6 +2249,12 @@ int sdhci_resume_host(struct sdhci_host *host)
ret = mmc_resume_host(host->mmc);
sdhci_enable_card_detection(host);
+ /* Set the re-tuning expiration flag */
+ if ((host->version >= SDHCI_SPEC_300) &&
+ host->tuning_count &&
+ (host->tuning_mode == SDHCI_TUNING_MODE_1))
+ host->flags |= SDHCI_NEEDS_RETUNING;
+
return ret;
}
@@ -2427,6 +2513,21 @@ int sdhci_add_host(struct sdhci_host *host)
if (caps[1] & SDHCI_DRIVER_TYPE_D)
mmc->caps |= MMC_CAP_DRIVER_TYPE_D;
+ /* Initial value for re-tuning timer count */
+ host->tuning_count = (caps[1] & SDHCI_RETUNING_TIMER_COUNT_MASK) >>
+ SDHCI_RETUNING_TIMER_COUNT_SHIFT;
+
+ /*
+ * In case Re-tuning Timer is not disabled, the actual value of
+ * re-tuning timer will be 2 ^ (n - 1).
+ */
+ if (host->tuning_count)
+ host->tuning_count = 1 << (host->tuning_count - 1);
+
+ /* Re-tuning mode supported by the Host Controller */
+ host->tuning_mode = (caps[1] & SDHCI_RETUNING_MODE_MASK) >>
+ SDHCI_RETUNING_MODE_SHIFT;
+
ocr_avail = 0;
/*
* According to SD Host Controller spec v3.00, if the Host System
@@ -2572,9 +2673,15 @@ int sdhci_add_host(struct sdhci_host *host)
setup_timer(&host->timer, sdhci_timeout_timer, (unsigned long)host);
- if (host->version >= SDHCI_SPEC_300)
+ if (host->version >= SDHCI_SPEC_300) {
init_waitqueue_head(&host->buf_ready_int);
+ /* Initialize re-tuning timer */
+ init_timer(&host->tuning_timer);
+ host->tuning_timer.data = (unsigned long)host;
+ host->tuning_timer.function = sdhci_tuning_timer;
+ }
+
ret = request_irq(host->irq, sdhci_irq, IRQF_SHARED,
mmc_hostname(mmc), host);
if (ret)
@@ -2668,6 +2775,8 @@ void sdhci_remove_host(struct sdhci_host *host, int dead)
free_irq(host->irq, host);
del_timer_sync(&host->timer);
+ if (host->version >= SDHCI_SPEC_300)
+ del_timer_sync(&host->tuning_timer);
tasklet_kill(&host->card_tasklet);
tasklet_kill(&host->finish_tasklet);
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index 4709091..376d56e 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -193,7 +193,11 @@
#define SDHCI_DRIVER_TYPE_A 0x00000010
#define SDHCI_DRIVER_TYPE_C 0x00000020
#define SDHCI_DRIVER_TYPE_D 0x00000040
-#define SDHCI_USE_SDR50_TUNING 0x00002000
+#define SDHCI_RETUNING_TIMER_COUNT_MASK 0x00000F00
+#define SDHCI_RETUNING_TIMER_COUNT_SHIFT 8
+#define SDHCI_USE_SDR50_TUNING 0x00002000
+#define SDHCI_RETUNING_MODE_MASK 0x0000C000
+#define SDHCI_RETUNING_MODE_SHIFT 14
#define SDHCI_CLOCK_MUL_MASK 0x00FF0000
#define SDHCI_CLOCK_MUL_SHIFT 16
diff --git a/include/linux/mmc/sdhci.h b/include/linux/mmc/sdhci.h
index 4be4022..c6539be 100644
--- a/include/linux/mmc/sdhci.h
+++ b/include/linux/mmc/sdhci.h
@@ -110,6 +110,7 @@ struct sdhci_host {
#define SDHCI_REQ_USE_DMA (1<<2) /* Use DMA for this req. */
#define SDHCI_DEVICE_DEAD (1<<3) /* Device unresponsive */
#define SDHCI_SDR50_NEEDS_TUNING (1<<4) /* SDR50 needs tuning */
+#define SDHCI_NEEDS_RETUNING (1<<5) /* Host needs retuning */
unsigned int version; /* SDHCI spec. version */
@@ -152,6 +153,11 @@ struct sdhci_host {
wait_queue_head_t buf_ready_int; /* Waitqueue for Buffer Read Ready interrupt */
unsigned int tuning_done; /* Condition flag set when CMD19 succeeds */
+ unsigned int tuning_count; /* Timer count for re-tuning */
+ unsigned int tuning_mode; /* Re-tuning mode supported by host */
+#define SDHCI_TUNING_MODE_1 0
+ struct timer_list tuning_timer; /* Timer for tuning */
+
unsigned long private[0] ____cacheline_aligned;
};
#endif /* __SDHCI_H */
--
1.7.1
--
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