[PATCH 1/4] mmc: mediatek: Fix CMD6 timeout issue
From: Ulf Hansson <hidden>
Date: 2016-12-01 09:52:50
Also in:
linux-devicetree, linux-mediatek, linux-mmc, lkml
On 8 November 2016 at 07:08, Yong Mao [off-list ref] wrote:
From: yong mao <redacted> When initializing EMMC, after switch to HS400, it will issue CMD6 to change ext_csd, if first CMD6 got CRC error, the repeat CMD6 may get timeout, that's because SDCBSY was cleared by msdc_reset_hw()
Sorry for the delay! We have recently been re-working the sequence for how to deal more properly with CMD6 in the mmc core. The changes done so far should mostly concern switches to HS and HS DDR, but I think you should run a re-test to make sure you still hit the same problems.
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Signed-off-by: Yong Mao <redacted> Signed-off-by: Chaotian Jing <chaotian.jing@mediatek.com> --- drivers/mmc/host/mtk-sd.c | 77 ++++++++++++++++++++++++++++++--------------- 1 file changed, 51 insertions(+), 26 deletions(-)diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c index 84e9afc..b29683b 100644 --- a/drivers/mmc/host/mtk-sd.c +++ b/drivers/mmc/host/mtk-sd.c@@ -826,6 +826,15 @@ static bool msdc_cmd_done(struct msdc_host *host, int events, return true; } +static int msdc_card_busy(struct mmc_host *mmc) +{ + struct msdc_host *host = mmc_priv(mmc); + u32 status = readl(host->base + MSDC_PS); + + /* check if data0 is low */ + return !(status & BIT(16)); +} + /* It is the core layer's responsibility to ensure card status * is correct before issue a request. but host design do below * checks recommended.
Hmm. Why? I think you should rely on the mmc core to invoke the ->card_busy() ops instead. The core knows better when it's needed. Perhaps that may also resolve some of these issues for you!?
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@@ -835,10 +844,20 @@ static inline bool msdc_cmd_is_ready(struct msdc_host *host, { /* The max busy time we can endure is 20ms */ unsigned long tmo = jiffies + msecs_to_jiffies(20); + u32 count = 0; + + if (in_interrupt()) { + while ((readl(host->base + SDC_STS) & SDC_STS_CMDBUSY) && + (count < 1000)) { + udelay(1); + count++;
This seems like a bad idea, "busy-wait" in irq context is never a good idea.
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+ } + } else { + while ((readl(host->base + SDC_STS) & SDC_STS_CMDBUSY) && + time_before(jiffies, tmo)) + cpu_relax(); + } - while ((readl(host->base + SDC_STS) & SDC_STS_CMDBUSY) && - time_before(jiffies, tmo)) - cpu_relax(); if (readl(host->base + SDC_STS) & SDC_STS_CMDBUSY) { dev_err(host->dev, "CMD bus busy detected\n"); host->error |= REQ_CMD_BUSY;@@ -846,17 +865,35 @@ static inline bool msdc_cmd_is_ready(struct msdc_host *host, return false; } - if (mmc_resp_type(cmd) == MMC_RSP_R1B || cmd->data) { - tmo = jiffies + msecs_to_jiffies(20); - /* R1B or with data, should check SDCBUSY */ - while ((readl(host->base + SDC_STS) & SDC_STS_SDCBUSY) && - time_before(jiffies, tmo)) - cpu_relax(); - if (readl(host->base + SDC_STS) & SDC_STS_SDCBUSY) { - dev_err(host->dev, "Controller busy detected\n"); - host->error |= REQ_CMD_BUSY; - msdc_cmd_done(host, MSDC_INT_CMDTMO, mrq, cmd); - return false; + if (cmd->opcode != MMC_SEND_STATUS) { + count = 0; + /* Consider that CMD6 crc error before card was init done, + * mmc_retune() will return directly as host->card is null. + * and CMD6 will retry 3 times, must ensure card is in transfer + * state when retry. + */ + tmo = jiffies + msecs_to_jiffies(60 * 1000); + while (1) { + if (msdc_card_busy(host->mmc)) { + if (in_interrupt()) { + udelay(1); + count++; + } else { + msleep_interruptible(10); + } + } else { + break; + } + /* Timeout if the device never + * leaves the program state. + */ + if (count > 1000 || time_after(jiffies, tmo)) { + pr_err("%s: Card stuck in programming state! %s\n", + mmc_hostname(host->mmc), __func__); + host->error |= REQ_CMD_BUSY; + msdc_cmd_done(host, MSDC_INT_CMDTMO, mrq, cmd); + return false; + }
This hole new code is a hack, that shouldn't be needed in the host driver. I think we need to investigate and fix the issue in the mmc core layer, to make this work for your host driver. That instead of doing a work around in the host.
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} } return true;@@ -1070,18 +1107,6 @@ static int msdc_ops_switch_volt(struct mmc_host *mmc, struct mmc_ios *ios) return ret; } -static int msdc_card_busy(struct mmc_host *mmc) -{ - struct msdc_host *host = mmc_priv(mmc); - u32 status = readl(host->base + MSDC_PS); - - /* check if any pin between dat[0:3] is low */ - if (((status >> 16) & 0xf) != 0xf) - return 1; - - return 0; -} - static void msdc_request_timeout(struct work_struct *work) { struct msdc_host *host = container_of(work, struct msdc_host, --1.7.9.5
Kind regards Uffe