Messages in this thread | | | Subject | Re: [PATCH 1/4] mmc: mmci: avoid fake busy polling | From | Ludovic BARRE <> | Date | Wed, 6 Mar 2019 10:04:21 +0100 |
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Hi Ulf
On 3/6/19 10:00 AM, Ulf Hansson wrote: > On Tue, 5 Mar 2019 at 17:10, Ludovic Barre <ludovic.Barre@st.com> wrote: >> >> From: Ludovic Barre <ludovic.barre@st.com> >> >> The busy status bit could occurred even if no busy response is >> expected (example cmd11). On sdmmc variant, the busy_detect_flag >> reflects inverted value of d0 state, it's sampled at the end of a >> CMD response and a second time 2 clk cycles after the CMD response. >> To avoid a fake busy, the busy status could be checked and polled >> only if the command has RSP_BUSY flag. >> >> Signed-off-by: Ludovic Barre <ludovic.barre@st.com> > > Before I review this, can you tell what HW you have tested this on?
I tested on stm32mp157c (stm32_sdmmc variant)
> > Kind regards > Uffe > >> --- >> drivers/mmc/host/mmci.c | 19 +++++++++++++------ >> 1 file changed, 13 insertions(+), 6 deletions(-) >> >> diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c >> index 387ff14..4901b73 100644 >> --- a/drivers/mmc/host/mmci.c >> +++ b/drivers/mmc/host/mmci.c >> @@ -1220,12 +1220,13 @@ mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd, >> unsigned int status) >> { >> void __iomem *base = host->base; >> - bool sbc; >> + bool sbc, busy_resp; >> >> if (!cmd) >> return; >> >> sbc = (cmd == host->mrq->sbc); >> + busy_resp = !!(cmd->flags & MMC_RSP_BUSY); >> >> /* >> * We need to be one of these interrupts to be considered worth >> @@ -1239,8 +1240,7 @@ mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd, >> /* >> * ST Micro variant: handle busy detection. >> */ >> - if (host->variant->busy_detect) { >> - bool busy_resp = !!(cmd->flags & MMC_RSP_BUSY); >> + if (busy_resp && host->variant->busy_detect) { >> >> /* We are busy with a command, return */ >> if (host->busy_status && >> @@ -1253,7 +1253,7 @@ mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd, >> * that the special busy status bit is still set before >> * proceeding. >> */ >> - if (!host->busy_status && busy_resp && >> + if (!host->busy_status && >> !(status & (MCI_CMDCRCFAIL|MCI_CMDTIMEOUT)) && >> (readl(base + MMCISTATUS) & host->variant->busy_detect_flag)) { >> >> @@ -1508,6 +1508,7 @@ static irqreturn_t mmci_irq(int irq, void *dev_id) >> { >> struct mmci_host *host = dev_id; >> u32 status; >> + bool busy_resp; >> int ret = 0; >> >> spin_lock(&host->lock); >> @@ -1550,9 +1551,15 @@ static irqreturn_t mmci_irq(int irq, void *dev_id) >> } >> >> /* >> - * Don't poll for busy completion in irq context. >> + * Don't poll for: >> + * -busy completion in irq context. >> + * -no busy response expected. >> */ >> - if (host->variant->busy_detect && host->busy_status) >> + busy_resp = host->cmd ? >> + !!(host->cmd->flags & MMC_RSP_BUSY) : false; >> + >> + if (host->variant->busy_detect && >> + (!busy_resp || host->busy_status)) >> status &= ~host->variant->busy_detect_flag; >> >> ret = 1; >> -- >> 2.7.4 >>
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