Messages in this thread Patch in this message | | | Subject | Re: [PATCH V5 1/3] mmc: mmci: add hardware busy timeout feature | From | Ludovic BARRE <> | Date | Wed, 4 Sep 2019 17:04:17 +0200 |
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hi Ulf
On 8/26/19 1:39 PM, Ulf Hansson wrote: > On Tue, 13 Aug 2019 at 12:00, Ludovic Barre <ludovic.Barre@st.com> wrote: >> >> From: Ludovic Barre <ludovic.barre@st.com> >> >> In some variants, the data timer starts and decrements >> when the DPSM enters in Wait_R or Busy state >> (while data transfer or MMC_RSP_BUSY), and generates a >> data timeout error if the counter reach 0. > > I don't quite follow here, sorry. Can you please try to elaborate on > the use case(s) more exactly? > > For example, what happens when a data transfer has just finished (for > example when MCI_DATAEND has been received) and we are going to send a > CMD12 to stop it? In this case the CMD12 has the MMC_RSP_BUSY flag > set. >
example with cmd25 (write multi block) mmci_request - mmci_start_data set MMCIDATATIMER, MMCIDATALENGTH, MMCIMASK0 - mmci_start_command: set MMCIARGUMENT, MMCICOMMAND (cmd25)
mmci_irq: - irq MCI_CMDRESPEND - irq MCI_DATAEND - send cmd12 => mmci_start_command(host->stop_abort or data->stop) these cmds have flag rsp_busy and no data associate host->cmd = cmd (host->stop_abort or data->stop) for next irq
mmci_irq: - irq MCI_CMDRESPEND - irq BUSYD0END - mmci_request_end
> Another example is the CMD5, which has no data with it. > >> >> -Define max_busy_timeout (in ms) according to clock. >> -Set data timer register if the command has rsp_busy flag. >> If busy_timeout is not defined by framework, the busy >> length after Data Burst is defined as 1 second >> (refer: 4.6.2.2 Write of sd specification part1 v6-0). > > One second is not sufficient for all operations, like ERASE for > example. However, I understand that you want to pick some value, as a > safety. I guess that's fine. > > I am thinking that if the command has the MMC_RSP_BUSY flag set, the > core should really provide a busy timeout for it. That said, maybe the > host driver should splat a WARN in case there is not busy timeout > specified.
Today, I just see a busy_timeout not defined on write request. On erase request, the timeout is defined in function mmc_do_erase. In core, there are several paths to done a write request, and I not be sure to fix all. For safety, I preferred fix with the max value of write request.
> >> -Add MCI_DATATIMEOUT error management in mmci_cmd_irq. >> >> Signed-off-by: Ludovic Barre <ludovic.barre@st.com> >> --- >> drivers/mmc/host/mmci.c | 37 ++++++++++++++++++++++++++++++++----- >> drivers/mmc/host/mmci.h | 3 +++ >> 2 files changed, 35 insertions(+), 5 deletions(-) >> >> diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c >> index c37e70dbe250..c50586540765 100644 >> --- a/drivers/mmc/host/mmci.c >> +++ b/drivers/mmc/host/mmci.c >> @@ -1075,6 +1075,7 @@ static void >> mmci_start_command(struct mmci_host *host, struct mmc_command *cmd, u32 c) >> { >> void __iomem *base = host->base; >> + unsigned long long clks = 0; >> >> dev_dbg(mmc_dev(host->mmc), "op %02x arg %08x flags %08x\n", >> cmd->opcode, cmd->arg, cmd->flags); >> @@ -1097,6 +1098,19 @@ mmci_start_command(struct mmci_host *host, struct mmc_command *cmd, u32 c) >> else >> c |= host->variant->cmdreg_srsp; >> } >> + >> + if (host->variant->busy_timeout && !host->mrq->data) { > > Suppose this is a CMD12 command, having the MMC_RSP_BUSY flag set. The > command would then be sent to stop the transmission and then > host->mrq->data would also be set.
Sorry, it's a mistake introduce by v5. I would keep the clear of datatimer when is not needed (no data & no rsp busy, see below). But on cmd23 (set_block_count) with datactrl_first variant property the datatimer should be protected.
To simplify and fix the code, I will remove the clear of datatimer when there is no data & no rsp busy.
- if (host->variant->busy_timeout && !host->mrq->data) { + if (host->variant->busy_timeout && !cmd->flags & MMC_RSP_BUSY) { + .... + writel_relaxed(clks, host->base + MMCIDATATIMER); + }
> > If I recall earlier what you stated about the new sdmmc variant, the > CMD12 is needed to exit the DPSM. Hence don't you need to re-program a > new value for the MMCIDATATIMER register for this scenario? > >> + if (cmd->flags & MMC_RSP_BUSY) { >> + if (!cmd->busy_timeout) >> + cmd->busy_timeout = 1000; >> + >> + clks = (unsigned long long)cmd->busy_timeout; >> + clks *= host->cclk; > > Any problems with putting the above on one line?
No, it was just to not exceed 80 characters.
> >> + do_div(clks, MSEC_PER_SEC); >> + } >> + writel_relaxed(clks, host->base + MMCIDATATIMER); > > This is writing zero to MMCIDATATIMER in case the MMC_RSP_BUSY isn't > set, is that on purpose?
It was to clear the datatimer when the command has no data & no rsp_busy. This allowed to look if the datatimer was used and not correctly set with the right value (with datatimeout).
Like said above, I will remove this and set datatimer only on rsp_busy flag.
> >> + } >> + >> if (/*interrupt*/0) >> c |= MCI_CPSM_INTERRUPT; >> >> @@ -1203,6 +1217,7 @@ mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd, >> { >> void __iomem *base = host->base; >> bool sbc, busy_resp; >> + u32 err_msk; >> >> if (!cmd) >> return; >> @@ -1215,8 +1230,12 @@ mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd, >> * handling. Note that we tag on any latent IRQs postponed >> * due to waiting for busy status. >> */ >> - if (!((status|host->busy_status) & >> - (MCI_CMDCRCFAIL|MCI_CMDTIMEOUT|MCI_CMDSENT|MCI_CMDRESPEND))) >> + err_msk = MCI_CMDCRCFAIL | MCI_CMDTIMEOUT; > > You might as well move the initial assignment of err_msk to the its > declaration above. >
OK, thx
>> + if (host->variant->busy_timeout && busy_resp) >> + err_msk |= MCI_DATATIMEOUT; >> + >> + if (!((status | host->busy_status) & >> + (err_msk | MCI_CMDSENT | MCI_CMDRESPEND))) >> return; >> >> /* Handle busy detection on DAT0 if the variant supports it. */ >> @@ -1235,8 +1254,7 @@ mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd, >> * while, to allow it to be set, but tests indicates that it >> * isn't needed. >> */ >> - if (!host->busy_status && >> - !(status & (MCI_CMDCRCFAIL|MCI_CMDTIMEOUT)) && >> + if (!host->busy_status && !(status & err_msk) && >> (readl(base + MMCISTATUS) & host->variant->busy_detect_flag)) { >> >> writel(readl(base + MMCIMASK0) | >> @@ -1290,6 +1308,9 @@ mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd, >> cmd->error = -ETIMEDOUT; >> } else if (status & MCI_CMDCRCFAIL && cmd->flags & MMC_RSP_CRC) { >> cmd->error = -EILSEQ; >> + } else if (host->variant->busy_timeout && busy_resp && >> + status & MCI_DATATIMEOUT) { >> + cmd->error = -ETIMEDOUT; >> } else { >> cmd->resp[0] = readl(base + MMCIRESPONSE0); >> cmd->resp[1] = readl(base + MMCIRESPONSE1); >> @@ -1948,6 +1969,8 @@ static int mmci_probe(struct amba_device *dev, >> * Enable busy detection. >> */ >> if (variant->busy_detect) { >> + u32 max_busy_timeout = 0; >> + >> mmci_ops.card_busy = mmci_card_busy; >> /* >> * Not all variants have a flag to enable busy detection >> @@ -1957,7 +1980,11 @@ static int mmci_probe(struct amba_device *dev, >> mmci_write_datactrlreg(host, >> host->variant->busy_dpsm_flag); >> mmc->caps |= MMC_CAP_WAIT_WHILE_BUSY; >> - mmc->max_busy_timeout = 0; >> + >> + if (variant->busy_timeout) >> + max_busy_timeout = ~0UL / (mmc->f_max / MSEC_PER_SEC); > > It looks like the max busy timeout is depending on the current picked > clock rate, right? > > In such case, perhaps it's better to update mmc->max_busy_timeout as > part of the ->set_ios() callback, as it's from there the clock rate > gets updated. Or what do you think?
yes, it's possible
> >> + >> + mmc->max_busy_timeout = max_busy_timeout; >> } >> >> /* Prepare a CMD12 - needed to clear the DPSM on some variants. */ >> diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h >> index 833236ecb31e..d8b7f6774e8f 100644 >> --- a/drivers/mmc/host/mmci.h >> +++ b/drivers/mmc/host/mmci.h >> @@ -287,6 +287,8 @@ struct mmci_host; >> * @signal_direction: input/out direction of bus signals can be indicated >> * @pwrreg_clkgate: MMCIPOWER register must be used to gate the clock >> * @busy_detect: true if the variant supports busy detection on DAT0. >> + * @busy_timeout: true if the variant starts data timer when the DPSM >> + * enter in Wait_R or Busy state. >> * @busy_dpsm_flag: bitmask enabling busy detection in the DPSM >> * @busy_detect_flag: bitmask identifying the bit in the MMCISTATUS register >> * indicating that the card is busy >> @@ -333,6 +335,7 @@ struct variant_data { >> u8 signal_direction:1; >> u8 pwrreg_clkgate:1; >> u8 busy_detect:1; >> + u8 busy_timeout:1; >> u32 busy_dpsm_flag; >> u32 busy_detect_flag; >> u32 busy_detect_mask; >> -- >> 2.17.1 >> > > Kind regards > Uffe >
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