Messages in this thread Patch in this message | | | Subject | Re: [PATCH] mmc: mmci: add variant property to send stop cmd if a command fail | From | Ludovic BARRE <> | Date | Fri, 2 Nov 2018 14:57:25 +0100 |
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hi Ulf
On 10/31/18 4:16 PM, Ulf Hansson wrote: > On 30 October 2018 at 11:16, Ludovic Barre <ludovic.Barre@st.com> wrote: >> From: Ludovic Barre <ludovic.barre@st.com> >> >> The mmc framework follows the requirement of SD_Specification: >> the STOP_TRANSMISSION is sent on multiple write/read commands >> and the stop command (alone), not needed on other ADTC commands. > > Well, there is a bit more to it than that. > > Host drivers may set MMC_CAP_CMD23 support, which means pre-defined > multi-block transfers, becomes preferable to open-ended ones. > > However, even for pre-defined transfers, a CM12 (stop transmission) > should be sent, in case of data transfer errors. At least if I > understand the specs correctly.
About CMD23 (sbc) yes are right, if you refer to "4.15 Set Block Count Command" of sd specification: -CMD23 is useful for the host to stop multiple read/write operation instead of CMD12. -"Host needs to issue CMD12 if any error is detected in the CMD18 and CMD25 operations" (multiple block read/write).
> > By looking at the code in mmci_data_irq(), I realize that it's not > considering this case - so I think that need to be fixed as to start > with.
for "it's not considering this case" you're referring to line: if (!data->stop || host->mrq->sbc) { mmci_request_end(host, data->mrq); } else { mmci_start_command(host, data->stop, 0); }
MMC framework, sets a data->stop command for requests read/write multi block: mmc_blk_data_prep: brq->stop.opcode = MMC_STOP_TRANSMISSION; mmc_blk_rw_rq_prep: brq->mrq.stop = &brq->stop
mmc_start_request mmc_mrq_prep if (mrq->stop) { mrq->data->stop = mrq->stop;
Normally, the framework set a data->stop command for sbc request. so we could replace the previous line by:
if (!data->stop || (host->mrq->sbc && !data->error)) mmci_request_end(host, data->mrq); else mmci_start_command(host, data->stop, 0);
> >> >> But, if an error happens on command or data step, some variants >> require a stop command "STOP_TRANSMISION" to clear the DPSM >> "Data Path State Machine". If it's not done the next data >> command freezes hardware block. >> Needed to support the STM32 sdmmc variant. > > I don't really follow this, sorry. Could you start by clarifying what > you mean by "data step", according to the above?
perhaps more explicit with: "if an error happens while command/data transmission
> > As far as I understand, you need to send a CMD12 to clear the DPSM, in > case of any errors happening during a data transfer (which includes > ADTC commands as well), right?
yes, that's right.
Regards Ludo
> > Or is there anything else to it? > > Kind regards > Uffe > >> >> Signed-off-by: Ludovic Barre <ludovic.barre@st.com> >> --- >> drivers/mmc/host/mmci.c | 33 +++++++++++++++++++++++++++++++++ >> drivers/mmc/host/mmci.h | 4 ++++ >> 2 files changed, 37 insertions(+) >> >> diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c >> index 19650ed..ecedca3 100644 >> --- a/drivers/mmc/host/mmci.c >> +++ b/drivers/mmc/host/mmci.c >> @@ -21,6 +21,7 @@ >> #include <linux/err.h> >> #include <linux/highmem.h> >> #include <linux/log2.h> >> +#include <linux/mmc/mmc.h> >> #include <linux/mmc/pm.h> >> #include <linux/mmc/host.h> >> #include <linux/mmc/card.h> >> @@ -57,6 +58,8 @@ void sdmmc_variant_init(struct mmci_host *host); >> #else >> static inline void sdmmc_variant_init(struct mmci_host *host) {} >> #endif >> +static void >> +mmci_start_command(struct mmci_host *host, struct mmc_command *cmd, u32 c); >> >> static unsigned int fmax = 515633; >> >> @@ -274,6 +277,7 @@ static struct variant_data variant_stm32_sdmmc = { >> .cmdreg_lrsp_crc = MCI_CPSM_STM32_LRSP_CRC, >> .cmdreg_srsp_crc = MCI_CPSM_STM32_SRSP_CRC, >> .cmdreg_srsp = MCI_CPSM_STM32_SRSP, >> + .cmdreg_stop = MCI_CPSM_STM32_CMDSTOP, >> .data_cmd_enable = MCI_CPSM_STM32_CMDTRANS, >> .irq_pio_mask = MCI_IRQ_PIO_STM32_MASK, >> .datactrl_first = true, >> @@ -574,6 +578,24 @@ void mmci_dma_error(struct mmci_host *host) >> static void >> mmci_request_end(struct mmci_host *host, struct mmc_request *mrq) >> { >> + /* >> + * If an error happens on command or data step, some variants >> + * require a stop command to reinit the DPSM. >> + * If it's not done the next data command freeze hardware block. >> + */ >> + if (host->variant->cmdreg_stop) { >> + u32 dpsm; >> + >> + dpsm = readl_relaxed(host->base + MMCISTATUS); >> + dpsm &= MCI_STM32_DPSMACTIVE; >> + >> + if (dpsm && ((mrq->cmd && mrq->cmd->error) || >> + (mrq->data && mrq->data->error))) { >> + mmci_start_command(host, &host->stop_abort, 0); >> + return; >> + } >> + } >> + >> writel(0, host->base + MMCICOMMAND); >> >> BUG_ON(host->data); >> @@ -1106,6 +1128,10 @@ mmci_start_command(struct mmci_host *host, struct mmc_command *cmd, u32 c) >> mmci_reg_delay(host); >> } >> >> + if (host->variant->cmdreg_stop && >> + cmd->opcode == MMC_STOP_TRANSMISSION) >> + c |= host->variant->cmdreg_stop; >> + >> c |= cmd->opcode | host->variant->cmdreg_cpsm_enable; >> if (cmd->flags & MMC_RSP_PRESENT) { >> if (cmd->flags & MMC_RSP_136) >> @@ -1957,6 +1983,13 @@ static int mmci_probe(struct amba_device *dev, >> mmc->max_busy_timeout = 0; >> } >> >> + /* prepare the stop command, used to abort and reinitialized the DPSM */ >> + if (variant->cmdreg_stop) { >> + host->stop_abort.opcode = MMC_STOP_TRANSMISSION; >> + host->stop_abort.arg = 0; >> + host->stop_abort.flags = MMC_RSP_R1B | MMC_CMD_AC; >> + } >> + >> mmc->ops = &mmci_ops; >> >> /* We support these PM capabilities. */ >> diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h >> index ec13d90..afb6ec4 100644 >> --- a/drivers/mmc/host/mmci.h >> +++ b/drivers/mmc/host/mmci.h >> @@ -166,6 +166,7 @@ >> #define MCI_ST_CEATAEND (1 << 23) >> #define MCI_ST_CARDBUSY (1 << 24) >> /* Extended status bits for the STM32 variants */ >> +#define MCI_STM32_DPSMACTIVE BIT(12) >> #define MCI_STM32_BUSYD0 BIT(20) >> >> #define MMCICLEAR 0x038 >> @@ -269,6 +270,7 @@ struct mmci_host; >> * @cmdreg_lrsp_crc: enable value for long response with crc >> * @cmdreg_srsp_crc: enable value for short response with crc >> * @cmdreg_srsp: enable value for short response without crc >> + * @cmdreg_stop: enable value for stop and abort transmission >> * @datalength_bits: number of bits in the MMCIDATALENGTH register >> * @fifosize: number of bytes that can be written when MMCI_TXFIFOEMPTY >> * is asserted (likewise for RX) >> @@ -322,6 +324,7 @@ struct variant_data { >> unsigned int cmdreg_lrsp_crc; >> unsigned int cmdreg_srsp_crc; >> unsigned int cmdreg_srsp; >> + unsigned int cmdreg_stop; >> unsigned int datalength_bits; >> unsigned int fifosize; >> unsigned int fifohalfsize; >> @@ -384,6 +387,7 @@ struct mmci_host { >> void __iomem *base; >> struct mmc_request *mrq; >> struct mmc_command *cmd; >> + struct mmc_command stop_abort; >> struct mmc_data *data; >> struct mmc_host *mmc; >> struct clk *clk; >> -- >> 2.7.4 >>
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