Re: [PATCH] mfd:rtsx: do retry when dma transfer error

From: Lee Jones
Date: Tue Jan 03 2017 - 12:15:28 EST


On Fri, 09 Dec 2016, steven_feng@xxxxxxxxxxxxxx wrote:

> From: steven_feng <steven_feng@xxxxxxxxxxxxxx>
>
> the request should be reissued when dma transfer error.
> for rts5227, the clock freq need to step reduce when error occurred.
>
> Signed-off-by: steven_feng <steven_feng@xxxxxxxxxxxxxx>
> ---
> drivers/mfd/rtsx_pcr.c | 15 +++++++++++++--
> include/linux/mfd/rtsx_pci.h | 2 ++
> 2 files changed, 15 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mfd/rtsx_pcr.c b/drivers/mfd/rtsx_pcr.c
> index 98029ee..1684e61 100644
> --- a/drivers/mfd/rtsx_pcr.c
> +++ b/drivers/mfd/rtsx_pcr.c
> @@ -30,6 +30,7 @@
> #include <linux/platform_device.h>
> #include <linux/mfd/core.h>
> #include <linux/mfd/rtsx_pci.h>
> +#include <linux/mmc/card.h>
> #include <asm/unaligned.h>
>
> #include "rtsx_pcr.h"
> @@ -452,8 +453,12 @@ int rtsx_pci_dma_transfer(struct rtsx_pcr *pcr, struct scatterlist *sglist,
> }
>
> spin_lock_irqsave(&pcr->lock, flags);
> - if (pcr->trans_result == TRANS_RESULT_FAIL)
> - err = -EINVAL;
> + if (pcr->trans_result == TRANS_RESULT_FAIL) {
> + err = -EILSEQ;

This seems strange. What is the reason for using this error?

> + if (pcr->dma_error_count < 8)

Why 8?

> + pcr->dma_error_count++;
> + }
> +
> else if (pcr->trans_result == TRANS_NO_DEVICE)
> err = -ENODEV;
> spin_unlock_irqrestore(&pcr->lock, flags);
> @@ -659,6 +664,11 @@ int rtsx_pci_switch_clock(struct rtsx_pcr *pcr, unsigned int card_clock,
> if (err < 0)
> return err;
>
> + if (card_clock == UHS_SDR104_MAX_DTR &&
> + pcr->dma_error_count && PCI_PID(pcr) == 0x5227)

Tabbing is off here.

What does 0x5227 mean? No magic numbers. Please define it.

> + card_clock = UHS_SDR104_MAX_DTR -
> + pcr->dma_error_count * 20000000;

What does this do?

Looks like you need a comment to describe what you're trying to
achieve.

> card_clock /= 1000000;
> pcr_dbg(pcr, "Switch card clock to %dMHz\n", card_clock);
>
> @@ -894,6 +904,7 @@ static irqreturn_t rtsx_pci_isr(int irq, void *dev_id)
> pcr->card_removed |= SD_EXIST;
> pcr->card_inserted &= ~SD_EXIST;
> }
> + pcr->dma_error_count = 0;
> }
>
> if (int_reg & MS_INT) {
> diff --git a/include/linux/mfd/rtsx_pci.h b/include/linux/mfd/rtsx_pci.h
> index 7eb7cba..1d65f4e 100644
> --- a/include/linux/mfd/rtsx_pci.h
> +++ b/include/linux/mfd/rtsx_pci.h
> @@ -957,6 +957,8 @@ struct rtsx_pcr {
>
> int num_slots;
> struct rtsx_slot *slots;
> +
> + u8 dma_error_count;
> };
>
> #define CHK_PCI_PID(pcr, pid) ((pcr)->pci->device == (pid))

--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org â Open source software for ARM SoCs
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