Hi Subhash,
> -----Original Message----- > From: Subhash Jadavani [mailto:subha...@codeaurora.org] > Sent: Wednesday, March 23, 2011 11:38 AM > To: Nath, Arindam; c...@laptop.org > Cc: zhangfei....@gmail.com; prak...@marvell.com; linux- > m...@vger.kernel.org; Su, Henry; Lu, Aaron; anath....@gmail.com > Subject: RE: [PATCH v2 09/12] mmc: sd: add support for tuning during > uhs initialization > > > > > -----Original Message----- > > From: linux-mmc-ow...@vger.kernel.org [mailto:linux-mmc- > > ow...@vger.kernel.org] On Behalf Of Nath, Arindam > > Sent: Monday, March 21, 2011 4:37 PM > > To: Subhash Jadavani; c...@laptop.org > > Cc: zhangfei....@gmail.com; prak...@marvell.com; linux- > > m...@vger.kernel.org; Su, Henry; Lu, Aaron; anath....@gmail.com > > Subject: RE: [PATCH v2 09/12] mmc: sd: add support for tuning during > > uhs initialization > > > > Hi Subhash, > > > > > > > -----Original Message----- > > > From: Subhash Jadavani [mailto:subha...@codeaurora.org] > > > Sent: Monday, March 21, 2011 4:29 PM > > > To: Nath, Arindam; c...@laptop.org > > > Cc: zhangfei....@gmail.com; prak...@marvell.com; linux- > > > m...@vger.kernel.org; Su, Henry; Lu, Aaron; anath....@gmail.com > > > Subject: RE: [PATCH v2 09/12] mmc: sd: add support for tuning > during > > > uhs initialization > > > > > > > > > > > > > -----Original Message----- > > > > From: Arindam Nath [mailto:anath....@gmail.com] On Behalf Of > > Arindam > > > > Nath > > > > Sent: Friday, March 04, 2011 5:03 PM > > > > To: c...@laptop.org > > > > Cc: zhangfei....@gmail.com; prak...@marvell.com; > > > > subha...@codeaurora.org; linux-mmc@vger.kernel.org; > > henry...@amd.com; > > > > aaron...@amd.com; anath....@gmail.com; Arindam Nath > > > > Subject: [PATCH v2 09/12] mmc: sd: add support for tuning during > > uhs > > > > initialization > > > > > > > > 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.n...@amd.com> > > > > --- > > > > 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) { > > > > + 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); > > > > > > > > > Why execute_tuning ops return type is void? Will there not be any > > error > > > scenarios? What if host fails to find any tuning point? Shouldn't > it > > > return > > > error to the core layer and then core layer should not begin with > the > > > any > > > read/write operations? > > > > In case the tuning procedure fails, Host Controller falls back on > using > > Fixed Sampling clock, so data transfer can still continue. > > > > I think that's not a correct assumption. Let's say tuning fails and > host > controller falls back to fixed sampling clock and card still operates > in > SDR104 with CLK=208MHz. This means that all further read/write > transactions > will mainly result in CRC Fail errors and none of the transactions may > be > successful. So we can't just leave the host controller in state where > it > cannot perform high speed transfers (because it's tuning had failed) > and > then start issuing commands with high speed transfer conditions > (CLK=208MHz). Better way is for host to inform core layer that tuning > has > failed and then there should not be any further transactions with the > card > or fallback to low speed modes (SDR12, SDR25 or SDR50) or power cycle > the > card. The host controller spec v3.00 clearly says that the occurrence of an error during tuning procedure is indicated by Sampling Select, which will be set to 0 in case tuning fails. But that won't stop the controller to retry re-tuning procedure based on the re-tuning mode. So I don't see any reason for transaction to be stopped in case tuning fails. Thanks, Arindam > > > > Thanks, > > Arindam > > > > > > > > > > > > }; > > > > > > > > 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 majord...@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
