On Fri, Aug 17, 2012 at 12:28 PM, S, Venkatraman <svenkatr@xxxxxx> wrote:
> On Fri, Aug 17, 2012 at 9:35 PM, Semen Protsenko <semen.protsenko@xxxxxx> wrote:
>> Errata description:
>> Due to a bad behavior of an internal signal, the Card Error interrupt bit
>> MMCHS_STAT[28] CERR may not be set sometimes when an error occurred in the
>> card response.
>>
>> Workaround:
>> After responses of type R1/R1b for all cards and responses of type R5/R5b/R6
>> for SD and SDIO cards, software must read two registers: MMCHS_RSP10 and
>> MMCHS_CSRE. When a MMCHS_CSRE[i] bit is set to 1, if the corresponding bit at
>> the same position in the response MMCHS_RSP10[i] is set to 1, the host
>> controller indicates a card error and software should proceed in the same way
>> as if a CERR interrupt would have been detected in the MMCHS_STAT register.
>>
>> Note:
>> This errata is applicable for omap44xx.
>>
>> Signed-off-by: Semen Protsenko <semen.protsenko@xxxxxx>
>
> The implementation looks fine, but can we simply not set the errata
> flag and make this as default
> behaviour ? I suppose the documented behaviour with CSRE and RSP10 is
> independent of the
> errata..
>
> Also, please send it to the linux-mmc list as well.
Vish>> We don't know if this errata effects OMAP5 as well. So, I think
we should only do this if we are OMAP4.
>
>> ---
>> drivers/mmc/host/omap_hsmmc.c | 38 ++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 38 insertions(+)
>>
>> diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
>> index 3a09f93..17803de 100644
>> --- a/drivers/mmc/host/omap_hsmmc.c
>> +++ b/drivers/mmc/host/omap_hsmmc.c
>> @@ -34,6 +34,7 @@
>> #include <linux/mmc/host.h>
>> #include <linux/mmc/core.h>
>> #include <linux/mmc/mmc.h>
>> +#include <linux/mmc/card.h>
>> #include <linux/io.h>
>> #include <linux/semaphore.h>
>> #include <linux/gpio.h>
>> @@ -47,6 +48,7 @@
>> /* OMAP HSMMC Host Controller Registers */
>> #define OMAP_HSMMC_SYSCONFIG 0x0010
>> #define OMAP_HSMMC_SYSSTATUS 0x0014
>> +#define OMAP_HSMMC_CSRE 0x0024
>> #define OMAP_HSMMC_CON 0x002C
>> #define OMAP_HSMMC_BLK 0x0104
>> #define OMAP_HSMMC_ARG 0x0108
>> @@ -117,6 +119,9 @@
>> #define OMAP_MMC_MAX_CLOCK 52000000
>> #define DRIVER_NAME "omap_hsmmc"
>>
>> +/* Errata definitions */
>> +#define OMAP_HSMMC_ERRATA_I761 BIT(0)
>> +
>> /*
>> * One controller can have multiple slots, like on some omap boards using
>> * omap.c controller driver. Luckily this is not currently done on any known
>> @@ -177,6 +182,7 @@ struct omap_hsmmc_host {
>> int reqs_blocked;
>> int use_reg;
>> int req_in_progress;
>> + unsigned int errata;
>> struct omap_hsmmc_next next_data;
>>
>> struct omap_mmc_platform_data *pdata;
>> @@ -857,6 +863,23 @@ omap_hsmmc_xfer_done(struct omap_hsmmc_host *host, struct mmc_data *data)
>> omap_hsmmc_start_command(host, data->stop, NULL);
>> }
>>
>> +static int
>> +omap_hsmmc_errata_i761(struct omap_hsmmc_host *host, struct mmc_command *cmd)
>> +{
>> + u32 rsp10, csre;
>> +
>> + if ((cmd->flags & MMC_RSP_R1) == MMC_RSP_R1
>> + || (host->mmc->card && (mmc_card_sd(host->mmc->card)
>> + || mmc_card_sdio(host->mmc->card))
>> + && (cmd->flags & MMC_RSP_R5))) {
>> + rsp10 = OMAP_HSMMC_READ(host->base, RSP10);
>> + csre = OMAP_HSMMC_READ(host->base, CSRE);
>> + return rsp10 & csre;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> /*
>> * Notify the core about command completion
>> */
>> @@ -1046,6 +1069,17 @@ static void omap_hsmmc_do_irq(struct omap_hsmmc_host *host, int status)
>> }
>> }
>>
>> + /* Errata i761 */
>> + if ((host->errata & OMAP_HSMMC_ERRATA_I761) && host->cmd
>> + && omap_hsmmc_errata_i761(host, host->cmd)) {
>> + /* Do the same as for CARD_ERR case */
>> + dev_dbg(mmc_dev(host->mmc), "Ignoring card err CMD%d\n",
>> + host->cmd->opcode);
>> + end_cmd = 1;
>> + if (host->data)
>> + end_trans = 1;
>> + }
>> +
>> OMAP_HSMMC_WRITE(host->base, STAT, status);
>>
>> if (end_cmd || ((status & CC) && host->cmd))
>> @@ -1829,6 +1863,10 @@ static int __devinit omap_hsmmc_probe(struct platform_device *pdev)
>> host->power_mode = MMC_POWER_OFF;
>> host->next_data.cookie = 1;
>>
>> + host->errata = 0;
>> + if (cpu_is_omap44xx())
>> + host->errata |= OMAP_HSMMC_ERRATA_I761;
>> +
>> platform_set_drvdata(pdev, host);
>>
>> mmc->ops = &omap_hsmmc_ops;
>> --
>> 1.7.10.4
>>
--
Regards,
Viswanath Puttagunta (Vish)
Android Kernel Software Engineer,
Texas Instruments
214-567-0838
vishp@xxxxxx
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