Hi Philip, > -----Original Message----- > From: Philip Rakity [mailto:prakity@xxxxxxxxxxx] > Sent: Saturday, March 05, 2011 12:04 AM > To: Nath, Arindam > Cc: cjb@xxxxxxxxxx; zhangfei.gao@xxxxxxxxx; subhashj@xxxxxxxxxxxxxx; > linux-mmc@xxxxxxxxxxxxxxx; Su, Henry; Lu, Aaron; anath.amd@xxxxxxxxx > Subject: Re: [PATCH v2 09/12] mmc: sd: add support for tuning during > uhs initialization > > > On Mar 4, 2011, at 3:32 AM, Arindam Nath 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; > > + 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) { > > safer to > reread > + ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2); > and now clear bits ? Agree on this. Will be fixed in next version. > > > + 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); > > msleep is better then mdelay ? The delay in this case is short enough, and also we have acquired spinlock, so I don't think msleep() is a good idea here. > > other option is to disable device interrupt > and check every ms if SDHCI_INT_DATA_AVAIL is set > and then enable device interrupt. The controller is supposed to > disable all other interrupts when doing tuning. > no need to mask interrupts. The unmask_irqs() at the beginning of function is to enable the controller to generate Buffer Read Ready interrupt, and we just disable it again before leaving the function using mask_irqs(). Thanks, Arindam > > > + > > + /* > > + * 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 > > > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
