Re: [PATCH v3] mfd:rtsx: do retry when dma transfer error

[冯伟linux]

> --- 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>
> Why is this required?
>
The UHS_SER104_MAX_DTR which is in "card_clock = UHS_SER104_MAX_DTR
 - (pcr->dma_error_count *20000000)" is defined in linux/mmc/card.h, so
it is required.

>  	spin_lock_irqsave(&pcr->lock, flags);
> -	if (pcr->trans_result == TRANS_RESULT_FAIL)
> -		err = -EINVAL;
> +	if (pcr->trans_result == TRANS_RESULT_FAIL) {
> +		err = -EILSEQ;
> "Illegal byte sequence", really?
>
This errno need to be -EILSEQ.

>>> +	if (card_clock == UHS_SDR104_MAX_DTR &&
>>> +		pcr->dma_error_count &&
>>> +		PCI_PID(pcr) == RTS5227_DEVICE_ID)
>>> +		card_clock = (UHS_SDR104_MAX_DTR -
>>> +			pcr->dma_error_count * 20000000);
> ... but won't this only reduce the clock frequency just once?
>
> There is no point bracketing the whole statement.
>
> But you do need to bracket one (the second) section of it.
>
The times of DMA transfer error occurrs recorded in dma_error_count,
When DMA transfer error occurrs, the card_clock is reduced by 20MHz.


Others are updated in PATCH v4
 

steven feng
Realsil Microelectronics CO. LTD.
Mobile：181-6899-0403  Ext：57594

On 2017年04月07日 19:13, Lee Jones wrote:
> On Fri, 07 Apr 2017, 冯伟linux wrote:
>
>> HI lee.jones
>>
>>     I submitted my  patch a few months ago, but the patch was not merged.
>> I want to know what causes this, so that I can update the patch and make
>> the patch merged.
> The patch was missed.  I do not know why.
>
>> steven feng
>> Realsil Microelectronics CO. LTD.
>> Mobile：181-6899-0403  Ext：57594
>>
>> On 2017年01月05日 17:01, 冯伟linux wrote:
>>> From: steven_feng <steven_feng@xxxxxxxxxxxxxx>
> Should be "Steven Feng"
>
>>> the request should be reissued when dma transfer error.
>>> for rts5227, the clock freq need to step reduce when error occurred.
> Please use correct grammar, including full-stops and capital letters.
>
>>> Signed-off-by: steven_feng <steven_feng@xxxxxxxxxxxxxx>
> "Steven Feng"
>
>>> ---
>>>  drivers/mfd/rtsx_pcr.c       | 17 +++++++++++++++--
>>>  include/linux/mfd/rtsx_pci.h |  5 +++++
>>>  2 files changed, 20 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/mfd/rtsx_pcr.c b/drivers/mfd/rtsx_pcr.c
>>> index 98029ee..3161c46 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>
> Why is this required?
>
>>>  #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;
> "Illegal byte sequence", really?
>
>>> +		if (pcr->dma_error_count < RTS_MAX_TIMES_FREQ_REDUCTION)
>>> +			pcr->dma_error_count++;
>>> +	}
>>> +
>>>  	else if (pcr->trans_result == TRANS_NO_DEVICE)
>>>  		err = -ENODEV;
>>>  	spin_unlock_irqrestore(&pcr->lock, flags);
>>> @@ -659,6 +664,13 @@ 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 */
> s/dma/DMA/
>
> I would reword as follows:
>
> "Reduce MMC card clock by 20MHz each time a DMA transfer error occurs"
>
>>> +	if (card_clock == UHS_SDR104_MAX_DTR &&
>>> +		pcr->dma_error_count &&
>>> +		PCI_PID(pcr) == RTS5227_DEVICE_ID)
>>> +		card_clock = (UHS_SDR104_MAX_DTR -
>>> +			pcr->dma_error_count * 20000000);
> ... but won't this only reduce the clock frequency just once?
>
> There is no point bracketing the whole statement.
>
> But you do need to bracket one (the second) section of it.
>
>>>  	card_clock /= 1000000;
>>>  	pcr_dbg(pcr, "Switch card clock to %dMHz\n", card_clock);
>>>  
>>> @@ -894,6 +906,7 @@ 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..116816f 100644
>>> --- a/include/linux/mfd/rtsx_pci.h
>>> +++ b/include/linux/mfd/rtsx_pci.h
>>> @@ -850,6 +850,9 @@
>>>  
>>>  #define rtsx_pci_init_cmd(pcr)		((pcr)->ci = 0)
>>>  
>>> +#define RTS5227_DEVICE_ID		0x5227
>>> +#define RTS_MAX_TIMES_FREQ_REDUCTION	8
>>> +
>>>  struct rtsx_pcr;
>>>  
>>>  struct pcr_handle {
>>> @@ -957,6 +960,8 @@ struct rtsx_pcr {
>>>  
>>>  	int				num_slots;
>>>  	struct rtsx_slot		*slots;
>>> +
>>> +	u8				dma_error_count;
>>>  };
>>>  
>>>  #define CHK_PCI_PID(pcr, pid)		((pcr)->pci->device == (pid))
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