Re: [PATCHv2] mmc: dw_mmc: change to use recommended reset procedure
On Mon, May 19, 2014 at 6:49 PM, Seungwon Jeon wrote:
> On Sat, May 17, 2014, Sonny Rao wrote:
>> On Tue, May 13, 2014 at 4:09 AM, Seungwon Jeon wrote:
>> > On Tuesday, May 13, Sonny Rao wrote:
>> >> On Mon, May 12, 2014 at 10:02 PM, Seungwon Jeon
>> >> wrote:
>> >> > As I mentioned in previous version, you put all reset stuff in existing
>> >> > fifo_reset function.
>> >> > Although databook mentions ciu_reset case for SBE error, it's not
>> >> > obvious when ciu_reset is
>> needed
>> >> in other error cases.
>> >> > If you intend to add some robust error handing, it would be better to
>> >> > make another function.
>> >>
>> >> The document I have actually doesn't mention error cases, it describes
>> >> this procedure as "Controller/DMA/FIFO Reset Usage" so I believe it is
>> >> saying this is the correct procedure in all cases, and based on our
>> >> testing it seems to work. I understand the skepticism, as I shared it
>> >> initially when I saw this, but based on our experience, this is
>> >> correct and it doesn't need to live in a separate function.
>> > I agree this active error handling.
>> > But, existing fifo_reset function is focused on fifo reset purely.
>> > I think your change is close to error recovery and it seems overloaded to
>> > basic function.
>> > So, you suggest renaming function for new sequence.
>>
>> I think the documentation says it should always be done, not just in
>> error recovery. I can rename the function to dw_mci_reset rather than
>> dw_mci_fifo_reset. Is that what you mean? Or do you mean make a new
>> function that is only called in error cases?
> Both are okay.
>
Ok
>>
>> > And look into dw_mci_work_routine_card(). dw_mci_idmac_reset() is
>> > redundancy.
>> > I expect it can be cleaned.
>> >
>> >
>> > /* Clear down the FIFO */
>> > dw_mci_fifo_reset(host);
>> > #ifdef CONFIG_MMC_DW_IDMAC
>> > dw_mci_idmac_reset(host);
>> > #endif
>> >
>> >
>>
>> Ok, I'll remove that extra reset, thanks for catching.
>>
>> >>
>> >> > Please check my comments below.
>> >> >
>> >> > On Tue, May 13, 2014, Sonny Rao wrote:
>> >> >> This patch changes the fifo reset code to follow the reset procedure
>> >> >> outlined in the documentation of Synopsys Mobile storage host databook
>> >> >> 7.2.13.
>> > Please remove this section number.
>> > No needed. It's old version.
>> >
>>
>> Ok
>>
>> >> >>
>> >> >> v2: Add Generic DMA support
>> >> >> per the documentation, move interrupt clear before wait
>> >> >> make the test for DMA host->use_dma rather than host->using_dma
>> >> >> add proper return values (although it appears no caller checks)
>> >> >>
>> >> >> Signed-off-by: Sonny Rao
>> >> >> Signed-off-by: Yuvaraj Kumar C D
>> >> >> ---
>> >> >> drivers/mmc/host/dw_mmc.c | 55
>> >> >> ++-
>> >> >> drivers/mmc/host/dw_mmc.h | 1 +
>> >> >> 2 files changed, 55 insertions(+), 1 deletion(-)
>> >> >>
>> >> >> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
>> >> >> index 55cd110..aff57e1 100644
>> >> >> --- a/drivers/mmc/host/dw_mmc.c
>> >> >> +++ b/drivers/mmc/host/dw_mmc.c
>> >> >> @@ -2325,6 +2325,7 @@ static bool dw_mci_ctrl_reset(struct dw_mci
>> >> >> *host, u32 reset)
>> >> >>
>> >> >> static inline bool dw_mci_fifo_reset(struct dw_mci *host)
>> >> >> {
>> >> >> + u32 flags = SDMMC_CTRL_RESET | SDMMC_CTRL_FIFO_RESET;
>> >> >> /*
>> >> >>* Reseting generates a block interrupt, hence setting
>> >> >>* the scatter-gather pointer to NULL.
>> >> >> @@ -2334,7 +2335,59 @@ static inline bool dw_mci_fifo_reset(struct
>> >> >> dw_mci *host)
>> >> >> host->sg = NULL;
>> >> >> }
>> >> >>
>> >> >> - return dw_mci_ctrl_reset(host, SDMMC_CTRL_FIFO_RESET);
>> >> >> + /*
>> >> >> + * The recommended method for resetting is to always reset the
>> >> >> + * controller and the fifo, but differs slightly depending on
>> >> >> the mode.
>> >> >> + * The Generic DMA mode (non IDMAC) also needs to reset DMA
>> >> >> where IDMAC
>> >> >> + * mode resets IDMAC at the end.
>> >> >> + *
>> >> >> + */
>> >> >> +#ifndef CONFIG_MMC_DW_IDMAC
>> >> > Is it added for generic DMA?
>> >> > IDMAC should be considered for dma_reseet as well.
>> >> > Please check databook.
>> >> >
>> >>
>> >> Yeah it's a little unclear. In the "7.2.13 Controller/DMA/FIFO Reset
>> >> Usage" part of the document they mention It is set for what they call
>> >> "generic" DMA, which I think is when there is an external DMA
>> >> controller, and the part below that it says for "DW-DMA/Non-DW-DMA"
>> >> that controller_reset and fifo_reset should be set. I believe this
>> >> "DW-DMA" case refers to what is called IDMAC. So, I think it's not
>> >> required for this case, but I admit I'm not sure why they also say
>> >> "Non-DW-DMA". If you know of a good way to differentia
RE: [PATCHv2] mmc: dw_mmc: change to use recommended reset procedure
On Sat, May 17, 2014, Sonny Rao wrote:
> On Tue, May 13, 2014 at 4:09 AM, Seungwon Jeon wrote:
> > On Tuesday, May 13, Sonny Rao wrote:
> >> On Mon, May 12, 2014 at 10:02 PM, Seungwon Jeon
> >> wrote:
> >> > As I mentioned in previous version, you put all reset stuff in existing
> >> > fifo_reset function.
> >> > Although databook mentions ciu_reset case for SBE error, it's not
> >> > obvious when ciu_reset is
> needed
> >> in other error cases.
> >> > If you intend to add some robust error handing, it would be better to
> >> > make another function.
> >>
> >> The document I have actually doesn't mention error cases, it describes
> >> this procedure as "Controller/DMA/FIFO Reset Usage" so I believe it is
> >> saying this is the correct procedure in all cases, and based on our
> >> testing it seems to work. I understand the skepticism, as I shared it
> >> initially when I saw this, but based on our experience, this is
> >> correct and it doesn't need to live in a separate function.
> > I agree this active error handling.
> > But, existing fifo_reset function is focused on fifo reset purely.
> > I think your change is close to error recovery and it seems overloaded to
> > basic function.
> > So, you suggest renaming function for new sequence.
>
> I think the documentation says it should always be done, not just in
> error recovery. I can rename the function to dw_mci_reset rather than
> dw_mci_fifo_reset. Is that what you mean? Or do you mean make a new
> function that is only called in error cases?
Both are okay.
>
> > And look into dw_mci_work_routine_card(). dw_mci_idmac_reset() is
> > redundancy.
> > I expect it can be cleaned.
> >
> >
> > /* Clear down the FIFO */
> > dw_mci_fifo_reset(host);
> > #ifdef CONFIG_MMC_DW_IDMAC
> > dw_mci_idmac_reset(host);
> > #endif
> >
> >
>
> Ok, I'll remove that extra reset, thanks for catching.
>
> >>
> >> > Please check my comments below.
> >> >
> >> > On Tue, May 13, 2014, Sonny Rao wrote:
> >> >> This patch changes the fifo reset code to follow the reset procedure
> >> >> outlined in the documentation of Synopsys Mobile storage host databook
> >> >> 7.2.13.
> > Please remove this section number.
> > No needed. It's old version.
> >
>
> Ok
>
> >> >>
> >> >> v2: Add Generic DMA support
> >> >> per the documentation, move interrupt clear before wait
> >> >> make the test for DMA host->use_dma rather than host->using_dma
> >> >> add proper return values (although it appears no caller checks)
> >> >>
> >> >> Signed-off-by: Sonny Rao
> >> >> Signed-off-by: Yuvaraj Kumar C D
> >> >> ---
> >> >> drivers/mmc/host/dw_mmc.c | 55
> >> >> ++-
> >> >> drivers/mmc/host/dw_mmc.h | 1 +
> >> >> 2 files changed, 55 insertions(+), 1 deletion(-)
> >> >>
> >> >> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> >> >> index 55cd110..aff57e1 100644
> >> >> --- a/drivers/mmc/host/dw_mmc.c
> >> >> +++ b/drivers/mmc/host/dw_mmc.c
> >> >> @@ -2325,6 +2325,7 @@ static bool dw_mci_ctrl_reset(struct dw_mci
> >> >> *host, u32 reset)
> >> >>
> >> >> static inline bool dw_mci_fifo_reset(struct dw_mci *host)
> >> >> {
> >> >> + u32 flags = SDMMC_CTRL_RESET | SDMMC_CTRL_FIFO_RESET;
> >> >> /*
> >> >>* Reseting generates a block interrupt, hence setting
> >> >>* the scatter-gather pointer to NULL.
> >> >> @@ -2334,7 +2335,59 @@ static inline bool dw_mci_fifo_reset(struct
> >> >> dw_mci *host)
> >> >> host->sg = NULL;
> >> >> }
> >> >>
> >> >> - return dw_mci_ctrl_reset(host, SDMMC_CTRL_FIFO_RESET);
> >> >> + /*
> >> >> + * The recommended method for resetting is to always reset the
> >> >> + * controller and the fifo, but differs slightly depending on the
> >> >> mode.
> >> >> + * The Generic DMA mode (non IDMAC) also needs to reset DMA where
> >> >> IDMAC
> >> >> + * mode resets IDMAC at the end.
> >> >> + *
> >> >> + */
> >> >> +#ifndef CONFIG_MMC_DW_IDMAC
> >> > Is it added for generic DMA?
> >> > IDMAC should be considered for dma_reseet as well.
> >> > Please check databook.
> >> >
> >>
> >> Yeah it's a little unclear. In the "7.2.13 Controller/DMA/FIFO Reset
> >> Usage" part of the document they mention It is set for what they call
> >> "generic" DMA, which I think is when there is an external DMA
> >> controller, and the part below that it says for "DW-DMA/Non-DW-DMA"
> >> that controller_reset and fifo_reset should be set. I believe this
> >> "DW-DMA" case refers to what is called IDMAC. So, I think it's not
> >> required for this case, but I admit I'm not sure why they also say
> >> "Non-DW-DMA". If you know of a good way to differentiate the "Generic
> >> DMA" case I can implement it. It wasn't clear to me if the driver
> >> even supported this "generic" dma case, but it sounds like it might,
> >> so I
Re: [PATCHv2] mmc: dw_mmc: change to use recommended reset procedure
On Tue, May 13, 2014 at 4:09 AM, Seungwon Jeon wrote:
> On Tuesday, May 13, Sonny Rao wrote:
>> On Mon, May 12, 2014 at 10:02 PM, Seungwon Jeon wrote:
>> > As I mentioned in previous version, you put all reset stuff in existing
>> > fifo_reset function.
>> > Although databook mentions ciu_reset case for SBE error, it's not obvious
>> > when ciu_reset is needed
>> in other error cases.
>> > If you intend to add some robust error handing, it would be better to make
>> > another function.
>>
>> The document I have actually doesn't mention error cases, it describes
>> this procedure as "Controller/DMA/FIFO Reset Usage" so I believe it is
>> saying this is the correct procedure in all cases, and based on our
>> testing it seems to work. I understand the skepticism, as I shared it
>> initially when I saw this, but based on our experience, this is
>> correct and it doesn't need to live in a separate function.
> I agree this active error handling.
> But, existing fifo_reset function is focused on fifo reset purely.
> I think your change is close to error recovery and it seems overloaded to
> basic function.
> So, you suggest renaming function for new sequence.
I think the documentation says it should always be done, not just in
error recovery. I can rename the function to dw_mci_reset rather than
dw_mci_fifo_reset. Is that what you mean? Or do you mean make a new
function that is only called in error cases?
> And look into dw_mci_work_routine_card(). dw_mci_idmac_reset() is redundancy.
> I expect it can be cleaned.
>
>
> /* Clear down the FIFO */
> dw_mci_fifo_reset(host);
> #ifdef CONFIG_MMC_DW_IDMAC
> dw_mci_idmac_reset(host);
> #endif
>
>
Ok, I'll remove that extra reset, thanks for catching.
>>
>> > Please check my comments below.
>> >
>> > On Tue, May 13, 2014, Sonny Rao wrote:
>> >> This patch changes the fifo reset code to follow the reset procedure
>> >> outlined in the documentation of Synopsys Mobile storage host databook
>> >> 7.2.13.
> Please remove this section number.
> No needed. It's old version.
>
Ok
>> >>
>> >> v2: Add Generic DMA support
>> >> per the documentation, move interrupt clear before wait
>> >> make the test for DMA host->use_dma rather than host->using_dma
>> >> add proper return values (although it appears no caller checks)
>> >>
>> >> Signed-off-by: Sonny Rao
>> >> Signed-off-by: Yuvaraj Kumar C D
>> >> ---
>> >> drivers/mmc/host/dw_mmc.c | 55
>> >> ++-
>> >> drivers/mmc/host/dw_mmc.h | 1 +
>> >> 2 files changed, 55 insertions(+), 1 deletion(-)
>> >>
>> >> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
>> >> index 55cd110..aff57e1 100644
>> >> --- a/drivers/mmc/host/dw_mmc.c
>> >> +++ b/drivers/mmc/host/dw_mmc.c
>> >> @@ -2325,6 +2325,7 @@ static bool dw_mci_ctrl_reset(struct dw_mci *host,
>> >> u32 reset)
>> >>
>> >> static inline bool dw_mci_fifo_reset(struct dw_mci *host)
>> >> {
>> >> + u32 flags = SDMMC_CTRL_RESET | SDMMC_CTRL_FIFO_RESET;
>> >> /*
>> >>* Reseting generates a block interrupt, hence setting
>> >>* the scatter-gather pointer to NULL.
>> >> @@ -2334,7 +2335,59 @@ static inline bool dw_mci_fifo_reset(struct dw_mci
>> >> *host)
>> >> host->sg = NULL;
>> >> }
>> >>
>> >> - return dw_mci_ctrl_reset(host, SDMMC_CTRL_FIFO_RESET);
>> >> + /*
>> >> + * The recommended method for resetting is to always reset the
>> >> + * controller and the fifo, but differs slightly depending on the
>> >> mode.
>> >> + * The Generic DMA mode (non IDMAC) also needs to reset DMA where
>> >> IDMAC
>> >> + * mode resets IDMAC at the end.
>> >> + *
>> >> + */
>> >> +#ifndef CONFIG_MMC_DW_IDMAC
>> > Is it added for generic DMA?
>> > IDMAC should be considered for dma_reseet as well.
>> > Please check databook.
>> >
>>
>> Yeah it's a little unclear. In the "7.2.13 Controller/DMA/FIFO Reset
>> Usage" part of the document they mention It is set for what they call
>> "generic" DMA, which I think is when there is an external DMA
>> controller, and the part below that it says for "DW-DMA/Non-DW-DMA"
>> that controller_reset and fifo_reset should be set. I believe this
>> "DW-DMA" case refers to what is called IDMAC. So, I think it's not
>> required for this case, but I admit I'm not sure why they also say
>> "Non-DW-DMA". If you know of a good way to differentiate the "Generic
>> DMA" case I can implement it. It wasn't clear to me if the driver
>> even supported this "generic" dma case, but it sounds like it might,
>> so I added this code. In practice, on the Exynos Systems we have,
>> which are using IDMAC, the reset procedure seems to work okay without
>> the dma_reset bit set, but I cannot test this "generic dma" case.
>>
>> The other places in the doc where I see them mention the dma_reset bit
>> are "7.2.21
RE: [PATCHv2] mmc: dw_mmc: change to use recommended reset procedure
On Tuesday, May 13, Sonny Rao wrote:
> On Mon, May 12, 2014 at 10:02 PM, Seungwon Jeon wrote:
> > As I mentioned in previous version, you put all reset stuff in existing
> > fifo_reset function.
> > Although databook mentions ciu_reset case for SBE error, it's not obvious
> > when ciu_reset is needed
> in other error cases.
> > If you intend to add some robust error handing, it would be better to make
> > another function.
>
> The document I have actually doesn't mention error cases, it describes
> this procedure as "Controller/DMA/FIFO Reset Usage" so I believe it is
> saying this is the correct procedure in all cases, and based on our
> testing it seems to work. I understand the skepticism, as I shared it
> initially when I saw this, but based on our experience, this is
> correct and it doesn't need to live in a separate function.
I agree this active error handling.
But, existing fifo_reset function is focused on fifo reset purely.
I think your change is close to error recovery and it seems overloaded to basic
function.
So, you suggest renaming function for new sequence.
And look into dw_mci_work_routine_card(). dw_mci_idmac_reset() is redundancy.
I expect it can be cleaned.
/* Clear down the FIFO */
dw_mci_fifo_reset(host);
#ifdef CONFIG_MMC_DW_IDMAC
dw_mci_idmac_reset(host);
#endif
>
> > Please check my comments below.
> >
> > On Tue, May 13, 2014, Sonny Rao wrote:
> >> This patch changes the fifo reset code to follow the reset procedure
> >> outlined in the documentation of Synopsys Mobile storage host databook
> >> 7.2.13.
Please remove this section number.
No needed. It's old version.
> >>
> >> v2: Add Generic DMA support
> >> per the documentation, move interrupt clear before wait
> >> make the test for DMA host->use_dma rather than host->using_dma
> >> add proper return values (although it appears no caller checks)
> >>
> >> Signed-off-by: Sonny Rao
> >> Signed-off-by: Yuvaraj Kumar C D
> >> ---
> >> drivers/mmc/host/dw_mmc.c | 55
> >> ++-
> >> drivers/mmc/host/dw_mmc.h | 1 +
> >> 2 files changed, 55 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> >> index 55cd110..aff57e1 100644
> >> --- a/drivers/mmc/host/dw_mmc.c
> >> +++ b/drivers/mmc/host/dw_mmc.c
> >> @@ -2325,6 +2325,7 @@ static bool dw_mci_ctrl_reset(struct dw_mci *host,
> >> u32 reset)
> >>
> >> static inline bool dw_mci_fifo_reset(struct dw_mci *host)
> >> {
> >> + u32 flags = SDMMC_CTRL_RESET | SDMMC_CTRL_FIFO_RESET;
> >> /*
> >>* Reseting generates a block interrupt, hence setting
> >>* the scatter-gather pointer to NULL.
> >> @@ -2334,7 +2335,59 @@ static inline bool dw_mci_fifo_reset(struct dw_mci
> >> *host)
> >> host->sg = NULL;
> >> }
> >>
> >> - return dw_mci_ctrl_reset(host, SDMMC_CTRL_FIFO_RESET);
> >> + /*
> >> + * The recommended method for resetting is to always reset the
> >> + * controller and the fifo, but differs slightly depending on the
> >> mode.
> >> + * The Generic DMA mode (non IDMAC) also needs to reset DMA where
> >> IDMAC
> >> + * mode resets IDMAC at the end.
> >> + *
> >> + */
> >> +#ifndef CONFIG_MMC_DW_IDMAC
> > Is it added for generic DMA?
> > IDMAC should be considered for dma_reseet as well.
> > Please check databook.
> >
>
> Yeah it's a little unclear. In the "7.2.13 Controller/DMA/FIFO Reset
> Usage" part of the document they mention It is set for what they call
> "generic" DMA, which I think is when there is an external DMA
> controller, and the part below that it says for "DW-DMA/Non-DW-DMA"
> that controller_reset and fifo_reset should be set. I believe this
> "DW-DMA" case refers to what is called IDMAC. So, I think it's not
> required for this case, but I admit I'm not sure why they also say
> "Non-DW-DMA". If you know of a good way to differentiate the "Generic
> DMA" case I can implement it. It wasn't clear to me if the driver
> even supported this "generic" dma case, but it sounds like it might,
> so I added this code. In practice, on the Exynos Systems we have,
> which are using IDMAC, the reset procedure seems to work okay without
> the dma_reset bit set, but I cannot test this "generic dma" case.
>
> The other places in the doc where I see them mention the dma_reset bit
> are "7.2.21 Transmission and Reception with Internal DMAC (IDMAC)"
> and the description of the CTRL register, and in "7.1
> Software/Hardware Restrictions" where they say it will terminate any
> pending transfer.
"DW-DMA" means Synopsys's DMA controller not IDMAC.
SDMMC_CTRL_DMA_RESET can apply in all type DMA interface.
>
> >> + if (host->use_dma)
> >> + flags |= SDMMC_CTRL_DMA_RESET;
> >> +#endif
> >> + if (dw_mci_ctrl_reset(host, flags)) {
> >> + /*
> >> +
Re: [PATCHv2] mmc: dw_mmc: change to use recommended reset procedure
On Monday 12 May 2014 18:38:41 Sonny Rao wrote: > +#ifndef CONFIG_MMC_DW_IDMAC > + if (host->use_dma) > + flags |= SDMMC_CTRL_DMA_RESET; > +#endif Can you change the above like this? if (IS_ENABLED(CONFIG_MMC_DW_IDMAC) && host->use_dma) flags |= SDMMC_CTRL_DMA_RESET; That is generally considered the preferred style these days. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCHv2] mmc: dw_mmc: change to use recommended reset procedure
On Mon, May 12, 2014 at 10:02 PM, Seungwon Jeon wrote:
> As I mentioned in previous version, you put all reset stuff in existing
> fifo_reset function.
> Although databook mentions ciu_reset case for SBE error, it's not obvious
> when ciu_reset is needed in other error cases.
> If you intend to add some robust error handing, it would be better to make
> another function.
The document I have actually doesn't mention error cases, it describes
this procedure as "Controller/DMA/FIFO Reset Usage" so I believe it is
saying this is the correct procedure in all cases, and based on our
testing it seems to work. I understand the skepticism, as I shared it
initially when I saw this, but based on our experience, this is
correct and it doesn't need to live in a separate function.
> Please check my comments below.
>
> On Tue, May 13, 2014, Sonny Rao wrote:
>> This patch changes the fifo reset code to follow the reset procedure
>> outlined in the documentation of Synopsys Mobile storage host databook
>> 7.2.13.
>>
>> v2: Add Generic DMA support
>> per the documentation, move interrupt clear before wait
>> make the test for DMA host->use_dma rather than host->using_dma
>> add proper return values (although it appears no caller checks)
>>
>> Signed-off-by: Sonny Rao
>> Signed-off-by: Yuvaraj Kumar C D
>> ---
>> drivers/mmc/host/dw_mmc.c | 55
>> ++-
>> drivers/mmc/host/dw_mmc.h | 1 +
>> 2 files changed, 55 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
>> index 55cd110..aff57e1 100644
>> --- a/drivers/mmc/host/dw_mmc.c
>> +++ b/drivers/mmc/host/dw_mmc.c
>> @@ -2325,6 +2325,7 @@ static bool dw_mci_ctrl_reset(struct dw_mci *host, u32
>> reset)
>>
>> static inline bool dw_mci_fifo_reset(struct dw_mci *host)
>> {
>> + u32 flags = SDMMC_CTRL_RESET | SDMMC_CTRL_FIFO_RESET;
>> /*
>>* Reseting generates a block interrupt, hence setting
>>* the scatter-gather pointer to NULL.
>> @@ -2334,7 +2335,59 @@ static inline bool dw_mci_fifo_reset(struct dw_mci
>> *host)
>> host->sg = NULL;
>> }
>>
>> - return dw_mci_ctrl_reset(host, SDMMC_CTRL_FIFO_RESET);
>> + /*
>> + * The recommended method for resetting is to always reset the
>> + * controller and the fifo, but differs slightly depending on the mode.
>> + * The Generic DMA mode (non IDMAC) also needs to reset DMA where IDMAC
>> + * mode resets IDMAC at the end.
>> + *
>> + */
>> +#ifndef CONFIG_MMC_DW_IDMAC
> Is it added for generic DMA?
> IDMAC should be considered for dma_reseet as well.
> Please check databook.
>
Yeah it's a little unclear. In the "7.2.13 Controller/DMA/FIFO Reset
Usage" part of the document they mention It is set for what they call
"generic" DMA, which I think is when there is an external DMA
controller, and the part below that it says for "DW-DMA/Non-DW-DMA"
that controller_reset and fifo_reset should be set. I believe this
"DW-DMA" case refers to what is called IDMAC. So, I think it's not
required for this case, but I admit I'm not sure why they also say
"Non-DW-DMA". If you know of a good way to differentiate the "Generic
DMA" case I can implement it. It wasn't clear to me if the driver
even supported this "generic" dma case, but it sounds like it might,
so I added this code. In practice, on the Exynos Systems we have,
which are using IDMAC, the reset procedure seems to work okay without
the dma_reset bit set, but I cannot test this "generic dma" case.
The other places in the doc where I see them mention the dma_reset bit
are "7.2.21 Transmission and Reception with Internal DMAC (IDMAC)"
and the description of the CTRL register, and in "7.1
Software/Hardware Restrictions" where they say it will terminate any
pending transfer.
>> + if (host->use_dma)
>> + flags |= SDMMC_CTRL_DMA_RESET;
>> +#endif
>> + if (dw_mci_ctrl_reset(host, flags)) {
>> + /*
>> + * In all cases we clear the RAWINTS register to clear any
>> + * interrupts.
>> + */
> I think interrupt masking is needed before reset because we will not handle
> it anymore.
> And Is there any reason to move interrupt clear here compared with previous
> version?
Yeah I moved it to match the description in the document more closely.
The documents mentioned doing the interrupt clear after setting the
reset bits, and before waiting for the dma_req bit in the status
register to clear. We've been running it with the interrupt clear
below the loop, for a while, and I just tested it with the clear above
the wait to make sure it still works properly and I was able to pass
the tuning process with some errors, so I believe this works fine too,
and more closely matches the description in the doc that I have.
>> + mci_writel(host, RINTSTS, 0x);
>> +
>> + /* if using dma we wait for dma_req to clear *
RE: [PATCHv2] mmc: dw_mmc: change to use recommended reset procedure
Sonny Rao wrote: > > This patch changes the fifo reset code to follow the reset procedure > outlined in the documentation of Synopsys Mobile storage host databook > 7.2.13. > > v2: Add Generic DMA support > per the documentation, move interrupt clear before wait > make the test for DMA host->use_dma rather than host->using_dma > add proper return values (although it appears no caller checks) Above changes should be put after following '---'. > > Signed-off-by: Sonny Rao > Signed-off-by: Yuvaraj Kumar C D > --- Here. - Kukjin > drivers/mmc/host/dw_mmc.c | 55 > ++- > drivers/mmc/host/dw_mmc.h | 1 + > 2 files changed, 55 insertions(+), 1 deletion(-) -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
RE: [PATCHv2] mmc: dw_mmc: change to use recommended reset procedure
As I mentioned in previous version, you put all reset stuff in existing
fifo_reset function.
Although databook mentions ciu_reset case for SBE error, it's not obvious when
ciu_reset is needed in other error cases.
If you intend to add some robust error handing, it would be better to make
another function.
Please check my comments below.
On Tue, May 13, 2014, Sonny Rao wrote:
> This patch changes the fifo reset code to follow the reset procedure
> outlined in the documentation of Synopsys Mobile storage host databook
> 7.2.13.
>
> v2: Add Generic DMA support
> per the documentation, move interrupt clear before wait
> make the test for DMA host->use_dma rather than host->using_dma
> add proper return values (although it appears no caller checks)
>
> Signed-off-by: Sonny Rao
> Signed-off-by: Yuvaraj Kumar C D
> ---
> drivers/mmc/host/dw_mmc.c | 55
> ++-
> drivers/mmc/host/dw_mmc.h | 1 +
> 2 files changed, 55 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index 55cd110..aff57e1 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -2325,6 +2325,7 @@ static bool dw_mci_ctrl_reset(struct dw_mci *host, u32
> reset)
>
> static inline bool dw_mci_fifo_reset(struct dw_mci *host)
> {
> + u32 flags = SDMMC_CTRL_RESET | SDMMC_CTRL_FIFO_RESET;
> /*
>* Reseting generates a block interrupt, hence setting
>* the scatter-gather pointer to NULL.
> @@ -2334,7 +2335,59 @@ static inline bool dw_mci_fifo_reset(struct dw_mci
> *host)
> host->sg = NULL;
> }
>
> - return dw_mci_ctrl_reset(host, SDMMC_CTRL_FIFO_RESET);
> + /*
> + * The recommended method for resetting is to always reset the
> + * controller and the fifo, but differs slightly depending on the mode.
> + * The Generic DMA mode (non IDMAC) also needs to reset DMA where IDMAC
> + * mode resets IDMAC at the end.
> + *
> + */
> +#ifndef CONFIG_MMC_DW_IDMAC
Is it added for generic DMA?
IDMAC should be considered for dma_reseet as well.
Please check databook.
> + if (host->use_dma)
> + flags |= SDMMC_CTRL_DMA_RESET;
> +#endif
> + if (dw_mci_ctrl_reset(host, flags)) {
> + /*
> + * In all cases we clear the RAWINTS register to clear any
> + * interrupts.
> + */
I think interrupt masking is needed before reset because we will not handle it
anymore.
And Is there any reason to move interrupt clear here compared with previous
version?
> + mci_writel(host, RINTSTS, 0x);
> +
> + /* if using dma we wait for dma_req to clear */
> + if (host->use_dma) {
> + unsigned long timeout = jiffies + msecs_to_jiffies(500);
> + u32 status;
> + do {
> + status = mci_readl(host, STATUS);
> + if (!(status & SDMMC_STATUS_DMA_REQ))
> + break;
> + cpu_relax();
What did you intend here?
If you intent busy-wait, how about using sleep instead?
> + } while (time_before(jiffies, timeout));
> +
> + if (status & SDMMC_STATUS_DMA_REQ) {
> + dev_err(host->dev,
> + "%s: Timeout waiting for dma_req to "
> + "clear during reset", __func__);
> + return false;
> + }
> +
> + /* when using DMA next we reset the fifo again */
> + dw_mci_ctrl_reset(host, SDMMC_CTRL_FIFO_RESET);
> + }
> + } else {
> + dev_err(host->dev, "%s: Reset bits didn't clear", __func__);
If ciu_reset is cleared, clk update below is needed?
Thanks,
Seungwon Jeon
> + return false;
> + }
> +
> +#ifdef CONFIG_MMC_DW_IDMAC
> + /* It is also recommended that we reset and reprogram idmac */
> + dw_mci_idmac_reset(host);
> +#endif
> +
> + /* After a CTRL reset we need to have CIU set clock registers */
> + mci_send_cmd(host->cur_slot, SDMMC_CMD_UPD_CLK, 0);
> +
> + return true;
> }
>
> static inline bool dw_mci_ctrl_all_reset(struct dw_mci *host)
> diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
> index 6bf24ab..2505804 100644
> --- a/drivers/mmc/host/dw_mmc.h
> +++ b/drivers/mmc/host/dw_mmc.h
> @@ -129,6 +129,7 @@
> #define SDMMC_CMD_INDX(n)((n) & 0x1F)
> /* Status register defines */
> #define SDMMC_GET_FCNT(x)(((x)>>17) & 0x1FFF)
> +#define SDMMC_STATUS_DMA_REQ BIT(31)
> /* FIFOTH register defines */
> #define SDMMC_SET_FIFOTH(m, r, t)(((m) & 0x7) << 28 | \
>((r) & 0xFFF) << 16 | \
> --
> 1.9.1.423.g4596e3a
>
> --
> To unsubscrib
