Re: [PATCH V2 03/27] mmc: mmci: convert dma_setup callback to return an int

From: Ulf Hansson
Date: Wed Sep 26 2018 - 19:50:23 EST


On 24 September 2018 at 18:12, Ludovic BARRE <ludovic.barre@xxxxxx> wrote:
> hi Ulf
>
>
> On 09/24/2018 04:28 PM, Ulf Hansson wrote:
>>
>> On 21 September 2018 at 11:45, Ludovic Barre <ludovic.Barre@xxxxxx> wrote:
>>>
>>> From: Ludovic Barre <ludovic.barre@xxxxxx>
>>>
>>> This patch converts dma_setup callback to return an integer
>>> This patch is needed to prepare sdmmc variant with internal dma
>>>
>>> Signed-off-by: Ludovic Barre <ludovic.barre@xxxxxx>
>>> ---
>>> drivers/mmc/host/mmci.c | 14 ++++++++++----
>>> drivers/mmc/host/mmci.h | 2 +-
>>> drivers/mmc/host/mmci_qcom_dml.c | 6 ++++--
>>> 3 files changed, 15 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
>>> index cbd67bc..2f845f3 100644
>>> --- a/drivers/mmc/host/mmci.c
>>> +++ b/drivers/mmc/host/mmci.c
>>> @@ -415,7 +415,7 @@ static void mmci_init_sg(struct mmci_host *host,
>>> struct mmc_data *data)
>>> * no custom DMA interfaces are supported.
>>> */
>>> #ifdef CONFIG_DMA_ENGINE
>>> -static void mmci_dma_setup(struct mmci_host *host)
>>> +static int mmci_dma_setup(struct mmci_host *host)
>>> {
>>> const char *rxname, *txname;
>>>
>>> @@ -466,7 +466,9 @@ static void mmci_dma_setup(struct mmci_host *host)
>>> }
>>>
>>> if (host->ops && host->ops->dma_setup)
>>> - host->ops->dma_setup(host);
>>> + return host->ops->dma_setup(host);
>>> +
>>
>>
>> Looks like you need to implement a error handling, instead of just
>> returning the error code.
>
>
> yes, today if a dma_setup is defined, we can't fallback to pio mode.
> A use_dma variable (defined in mmci_host) could be setted follow the return
> code of ops->dma_setup
>
> example:
>
> void mmci_dma_setup(struct mmci_host *host)
> {
> int err;
>
> if (!host->ops || !host->ops->dma_setup)
> return;
>
> err = host->ops->dma_setup(host);
> if (err)
> return;
>
> host->use_dma = true;
>
> /* initialize pre request cookie */
> host->next_cookie = 1;
> }
>
> use_dma variable could be check by mmci_host_ops variant functions.
>
> are you agree with this proposal?
>

Yep, makes sense!

>
>>
>>> + return 0;
>>> }
>>>
>>> /*
>>> @@ -741,8 +743,10 @@ static void mmci_post_request(struct mmc_host *mmc,
>>> struct mmc_request *mrq,
>>> static void mmci_get_next_data(struct mmci_host *host, struct mmc_data
>>> *data)
>>> {
>>> }
>>> -static inline void mmci_dma_setup(struct mmci_host *host)
>>> +
>>> +static inline int mmci_dma_setup(struct mmci_host *host)
>>> {
>>> + return 0;
>>> }
>>>
>>> static inline void mmci_dma_release(struct mmci_host *host)
>>> @@ -1796,7 +1800,9 @@ static int mmci_probe(struct amba_device *dev,
>>> amba_rev(dev), (unsigned long long)dev->res.start,
>>> dev->irq[0], dev->irq[1]);
>>>
>>> - mmci_dma_setup(host);
>>> + ret = mmci_dma_setup(host);
>>> + if (ret)
>>> + goto clk_disable;
>>>
>>> pm_runtime_set_autosuspend_delay(&dev->dev, 50);
>>> pm_runtime_use_autosuspend(&dev->dev);
>>> diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
>>> index 21aaf9a..06299ac 100644
>>> --- a/drivers/mmc/host/mmci.h
>>> +++ b/drivers/mmc/host/mmci.h
>>> @@ -273,7 +273,7 @@ struct variant_data {
>>>
>>> /* mmci variant callbacks */
>>> struct mmci_host_ops {
>>> - void (*dma_setup)(struct mmci_host *host);
>>> + int (*dma_setup)(struct mmci_host *host);
>>> };
>>>
>>> struct mmci_host_next {
>>> diff --git a/drivers/mmc/host/mmci_qcom_dml.c
>>> b/drivers/mmc/host/mmci_qcom_dml.c
>>> index be3fab5..1bb59cf 100644
>>> --- a/drivers/mmc/host/mmci_qcom_dml.c
>>> +++ b/drivers/mmc/host/mmci_qcom_dml.c
>>> @@ -119,7 +119,7 @@ static int of_get_dml_pipe_index(struct device_node
>>> *np, const char *name)
>>> }
>>>
>>> /* Initialize the dml hardware connected to SD Card controller */
>>> -static void qcom_dma_setup(struct mmci_host *host)
>>> +static int qcom_dma_setup(struct mmci_host *host)
>>> {
>>> u32 config;
>>> void __iomem *base;
>>> @@ -131,7 +131,7 @@ static void qcom_dma_setup(struct mmci_host *host)
>>>
>>> if (producer_id < 0 || consumer_id < 0) {
>>> host->variant->qcom_dml = false;
>>
>>
>> It seems like the existing code is an attempt to fallback to use pio
>> mode. However, I doubt it works as is.
>
>
> oops, I seen that like a variant identification issue, so if it's a
> fallback to pio mode it doesn't work.

Right. Let's see if we can get some input from Srinivas, else I will
run some test on my 410c board to see the behavior - very soon.

[...]

Kind regards
Uffe