Re: [PATCH v2] mfd:rtsx: do retry when dma transfer error

Lee Jones
2017-01-04T12:15:57Z

On Wed, 04 Jan 2017, steven_feng@realsil.com.cn wrote:

> From: steven_feng <steven_feng@realsil.com.cn>
>
> 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@realsil.com.cn>
> ---
> drivers/mfd/rtsx_pcr.c | 16 ++++++++++++++--
> include/linux/mfd/rtsx_pci.h | 4 ++++
> 2 files changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mfd/rtsx_pcr.c b/drivers/mfd/rtsx_pcr.c
> index 98029ee..63ee0ac 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;

Why are you using this error code?

> + if (pcr->dma_error_count < 8)

Please define the 8.

RTSX_MAX_FREQ_REDUCTIONS or similar.

> + pcr->dma_error_count++;
> + }
> +
> else if (pcr->trans_result == TRANS_NO_DEVICE)
> err = -ENODEV;
> spin_unlock_irqrestore(&pcr->lock, flags);
> @@ -659,6 +664,12 @@ int rtsx_pci_switch_clock(struct rtsx_pcr *pcr, unsigned int card_clock,
> if (err < 0)
> return err;
>
> + /* each time dma transfer error occurs, card clock decreased by 20MHz */

"Each"

> + if (card_clock == UHS_SDR104_MAX_DTR &&
> + pcr->dma_error_count && PCI_PID(pcr) == RTS5227_DEVICE_ID)

Suggest placing "PCI_PID(pcr) == RTS5227_DEVICE_ID" on a new line.

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

Suggest placing parantheis around:

(UHS_SDR104_MAX_DTR - pcr->dma_error_count)

> card_clock /= 1000000;
> pcr_dbg(pcr, "Switch card clock to %dMHz\n", card_clock);
>
> @@ -894,6 +905,7 @@ 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..751c4042 100644
> --- a/include/linux/mfd/rtsx_pci.h
> +++ b/include/linux/mfd/rtsx_pci.h
> @@ -850,6 +850,8 @@
>
> #define rtsx_pci_init_cmd(pcr) ((pcr)->ci = 0)
>
> +#define RTS5227_DEVICE_ID 0x5227
> +
> struct rtsx_pcr;
>
> struct pcr_handle {
> @@ -957,6 +959,8 @@ 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 │ Open source software for ARM SoCs
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