On Fri, Mar 4, 2011 at 6:32 AM, Arindam Nath <arindam.nath@xxxxxxx> wrote:
> Host Controller needs tuning during initialization to operate SDR50
> and SDR104 UHS-I cards. Whether SDR50 mode actually needs tuning is
> indicated by bit 45 of the Host Controller Capabilities register.
> A new command CMD19 has been defined in the Physical Layer spec
> v3.01 to request the card to send tuning pattern.
>
> We enable Buffer Read Ready interrupt at the very begining of tuning
> procedure, because that is the only interrupt generated by the Host
> Controller during tuning. The tuning block is sent by the card to the
> Host Controller using DAT lines, so we set Data Present Select (bit 5)
> in the Command register. The Host Controller is responsible for doing
> the verfication of tuning block sent by the card at the hardware level.
> After sending CMD19, we wait for Buffer Read Ready interrupt. In case
> we don't receive an interrupt after the specified timeout value, we
> fall back on fixed sampling clock by setting Execute Tuning (bit 6)
> and Sampling Clock Seletc (bit 7) of Host Control2 register to 0.
> Before exiting the tuning procedure, we disable Buffer Read Ready
> interrupt.
>
> Signed-off-by: Arindam Nath <arindam.nath@xxxxxxx>
> ---
> drivers/mmc/core/sd.c | 4 +
> drivers/mmc/host/sdhci.c | 137 ++++++++++++++++++++++++++++++++++++++++++++-
> drivers/mmc/host/sdhci.h | 3 +
> include/linux/mmc/host.h | 1 +
> include/linux/mmc/mmc.h | 1 +
> include/linux/mmc/sdhci.h | 4 +
> 6 files changed, 149 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
> index be01397..1e2d157 100644
> --- a/drivers/mmc/core/sd.c
> +++ b/drivers/mmc/core/sd.c
> @@ -637,6 +637,10 @@ static int mmc_sd_init_uhs_card(struct mmc_card *card)
> /* Set current limit for the card */
> err = sd_set_current_limit(card, status);
>
> + /* SPI mode doesn't define CMD19 */
> + if (!mmc_host_is_spi(card->host) && card->host->ops->execute_tuning)
> + card->host->ops->execute_tuning(card->host);
> +
> out:
> kfree(status);
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 245cc39..8f4f102 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -39,6 +39,8 @@
> #define SDHCI_USE_LEDS_CLASS
> #endif
>
> +#define MAX_TUNING_LOOP 40
> +
> static unsigned int debug_quirks = 0;
>
> static void sdhci_prepare_data(struct sdhci_host *, struct mmc_data *);
> @@ -985,7 +987,9 @@ static void sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd)
> flags |= SDHCI_CMD_CRC;
> if (cmd->flags & MMC_RSP_OPCODE)
> flags |= SDHCI_CMD_INDEX;
> - if (cmd->data)
> +
> + /* CMD19 is special in that the Data Present Select should be set */
> + if (cmd->data || (cmd->opcode == MMC_SEND_TUNING_BLOCK))
> flags |= SDHCI_CMD_DATA;
>
> sdhci_writew(host, SDHCI_MAKE_CMD(cmd->opcode, flags), SDHCI_COMMAND);
> @@ -1485,6 +1489,119 @@ static int sdhci_get_max_current_180(struct mmc_host *mmc)
> return max_current_180;
> }
>
> +static void sdhci_execute_tuning(struct mmc_host *mmc)
> +{
> + struct sdhci_host *host;
> + u16 ctrl;
> + int tuning_loop_counter = MAX_TUNING_LOOP;
> + unsigned long flags;
> + unsigned long timeout;
> +
> + host = mmc_priv(mmc);
> +
> + spin_lock_irqsave(&host->lock, flags);
> +
> + ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
> +
> + /*
> + * Host Controller needs tuning only in case of SDR104 mode
> + * and for SDR50 mode when Use Tuning for SDR50 is set in
> + * Capabilities register.
> + */
> + if ((ctrl & SDHCI_CTRL_UHS_SDR104) ||
> + ((ctrl & SDHCI_CTRL_UHS_SDR50) &&
> + (host->flags & SDHCI_SDR50_NEEDS_TUNING)))
> + ctrl |= SDHCI_CTRL_EXEC_TUNING;
> + else {
> + spin_unlock_irqrestore(&host->lock, flags);
> + return;
> + }
> +
> + sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
> +
> + /*
> + * As per the Host Controller spec v3.00, tuning command
> + * generates Buffer Read Ready interrupt, so enable that.
> + */
> + sdhci_unmask_irqs(host, SDHCI_INT_DATA_AVAIL);
> +
> + /*
> + * Issue CMD19 repeatedly till Execute Tuning is set to 0 or the number
> + * of loops reaches 40 times or a timeout of 150ms occurs.
> + */
> + timeout = 150;
> + do {
> + struct mmc_command cmd;
> + struct mmc_request mrq;
> +
> + if (!tuning_loop_counter && !timeout)
> + break;
> +
> + memset(&cmd, 0, sizeof(struct mmc_command));
> + cmd.opcode = MMC_SEND_TUNING_BLOCK;
> + cmd.arg = 0;
> + cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;
> +
> + memset(&cmd.resp, 0, sizeof(cmd.resp));
> + cmd.retries = 0;
> +
> + cmd.data = NULL;
> + cmd.error = 0;
> +
> + memset(&mrq, 0, sizeof(struct mmc_request));
> + mrq.cmd = &cmd;
> + host->mrq = &mrq;
Tune may fail since SDHCI_TRNS_DMA is set in SDHCI_TRANSFER_MODE,
SDHCI_TRNS_DMA required to be cleared before send_command, such as
sdhci_writew(host, 0x12, SDHCI_TRANSFER_MODE);
> + sdhci_send_command(host, &cmd);
> +
> + host->cmd = NULL;
> + host->mrq = NULL;
> +
> + spin_unlock_irqrestore(&host->lock, flags);
> +
> + /* Wait for Buffer Read Ready interrupt */
> + wait_event_interruptible_timeout(host->buf_ready_int,
> + (host->tuning_done == 1),
> + msecs_to_jiffies(50));
> + spin_lock_irqsave(&host->lock, flags);
> +
> + if (!host->tuning_done) {
> + printk(KERN_INFO DRIVER_NAME ": Tuning procedure"
> + " failed, falling back to fixed sampling"
> + " clock\n");
> + ctrl &= ~SDHCI_CTRL_TUNED_CLK;
> + ctrl &= ~SDHCI_CTRL_EXEC_TUNING;
> + sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
> +
> + goto out;
> + }
> +
> + host->tuning_done = 0;
> +
> + ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
> + tuning_loop_counter--;
> + timeout--;
> + mdelay(1);
> + } while (ctrl & SDHCI_CTRL_EXEC_TUNING);
> +
> + /*
> + * The Host Driver has exhausted the maximum number of loops allowed,
> + * so use fixed sampling frequency.
> + */
> + if (!tuning_loop_counter || !timeout) {
> + ctrl &= ~SDHCI_CTRL_TUNED_CLK;
> + sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
> + } else {
> + if (!(ctrl & SDHCI_CTRL_TUNED_CLK))
> + printk(KERN_INFO DRIVER_NAME ": Tuning procedure"
> + " failed, falling back to fixed sampling"
> + " clock\n");
> + }
> +
> +out:
> + sdhci_mask_irqs(host, SDHCI_INT_DATA_AVAIL);
> + spin_unlock_irqrestore(&host->lock, flags);
> +}
> +
> static const struct mmc_host_ops sdhci_ops = {
> .request = sdhci_request,
> .set_ios = sdhci_set_ios,
> @@ -1492,6 +1609,7 @@ static const struct mmc_host_ops sdhci_ops = {
> .enable_sdio_irq = sdhci_enable_sdio_irq,
> .start_signal_voltage_switch = sdhci_start_signal_voltage_switch,
> .get_max_current_180 = sdhci_get_max_current_180,
> + .execute_tuning = sdhci_execute_tuning,
> };
>
> /*****************************************************************************\
> @@ -1703,6 +1821,16 @@ static void sdhci_data_irq(struct sdhci_host *host, u32 intmask)
> {
> BUG_ON(intmask == 0);
>
> + /* CMD19 generates _only_ Buffer Read Ready interrupt */
> + if (intmask & SDHCI_INT_DATA_AVAIL) {
> + if (SDHCI_GET_CMD(sdhci_readw(host, SDHCI_COMMAND))
> + == MMC_SEND_TUNING_BLOCK) {
> + host->tuning_done = 1;
> + wake_up(&host->buf_ready_int);
> + return;
> + }
> + }
> +
> if (!host->data) {
> /*
> * The "data complete" interrupt is also used to
> @@ -2126,6 +2254,10 @@ int sdhci_add_host(struct sdhci_host *host)
> if (caps[1] & SDHCI_SUPPORT_DDR50)
> mmc->caps |= MMC_CAP_UHS_DDR50;
>
> + /* Does the host needs tuning for SDR50? */
> + if (caps[1] & SDHCI_USE_SDR50_TUNING)
> + host->flags |= SDHCI_SDR50_NEEDS_TUNING;
> +
> /* Driver Type(s) (A, C, D) supported by the host */
> if (caps[1] & SDHCI_DRIVER_TYPE_A)
> mmc->caps |= MMC_CAP_DRIVER_TYPE_A;
> @@ -2269,6 +2401,9 @@ int sdhci_add_host(struct sdhci_host *host)
>
> setup_timer(&host->timer, sdhci_timeout_timer, (unsigned long)host);
>
> + if (host->version >= SDHCI_SPEC_300)
> + init_waitqueue_head(&host->buf_ready_int);
> +
> ret = request_irq(host->irq, sdhci_irq, IRQF_SHARED,
> mmc_hostname(mmc), host);
> if (ret)
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index 5bf244d..4746879 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -160,6 +160,8 @@
> #define SDHCI_CTRL_DRV_TYPE_A 0x0010
> #define SDHCI_CTRL_DRV_TYPE_C 0x0020
> #define SDHCI_CTRL_DRV_TYPE_D 0x0030
> +#define SDHCI_CTRL_EXEC_TUNING 0x0040
> +#define SDHCI_CTRL_TUNED_CLK 0x0080
> #define SDHCI_CTRL_PRESET_VAL_ENABLE 0x8000
>
> #define SDHCI_CAPABILITIES 0x40
> @@ -187,6 +189,7 @@
> #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_CAPABILITIES_1 0x44
>
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index e84cd05..651e40b 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -129,6 +129,7 @@ struct mmc_host_ops {
>
> int (*start_signal_voltage_switch)(struct mmc_host *host);
> int (*get_max_current_180)(struct mmc_host *mmc);
> + void (*execute_tuning)(struct mmc_host *host);
> };
>
> struct mmc_card;
> diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
> index 612301f..9194f9e 100644
> --- a/include/linux/mmc/mmc.h
> +++ b/include/linux/mmc/mmc.h
> @@ -50,6 +50,7 @@
> #define MMC_SET_BLOCKLEN 16 /* ac [31:0] block len R1 */
> #define MMC_READ_SINGLE_BLOCK 17 /* adtc [31:0] data addr R1 */
> #define MMC_READ_MULTIPLE_BLOCK 18 /* adtc [31:0] data addr R1 */
> +#define MMC_SEND_TUNING_BLOCK 19 /* adtc R1 */
>
> /* class 3 */
> #define MMC_WRITE_DAT_UNTIL_STOP 20 /* adtc [31:0] data addr R1 */
> diff --git a/include/linux/mmc/sdhci.h b/include/linux/mmc/sdhci.h
> index 282d158..5203b97 100644
> --- a/include/linux/mmc/sdhci.h
> +++ b/include/linux/mmc/sdhci.h
> @@ -109,6 +109,7 @@ struct sdhci_host {
> #define SDHCI_USE_ADMA (1<<1) /* Host is ADMA capable */
> #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 */
>
> unsigned int version; /* SDHCI spec. version */
>
> @@ -147,6 +148,9 @@ struct sdhci_host {
>
> struct mmc_command *saved_abort_cmd; /* Abort command saved for data error recovery */
>
> + wait_queue_head_t buf_ready_int; /* Waitqueue for Buffer Read Ready interrupt */
> + unsigned int tuning_done; /* Condition flag set when CMD19 succeeds */
> +
> unsigned long private[0] ____cacheline_aligned;
> };
> #endif /* __SDHCI_H */
> --
> 1.7.1
>
>
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