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Date: Wed, 3 Oct 2018 13:44:01 +0200
From: Ludovic BARRE <ludovic.barre@...com>
To: Ulf Hansson <ulf.hansson@...aro.org>
CC: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
Rob Herring <robh+dt@...nel.org>,
Maxime Coquelin <mcoquelin.stm32@...il.com>,
Alexandre Torgue <alexandre.torgue@...com>,
Benjamin Gaignard <benjamin.gaignard@...aro.org>,
Gerald Baeza <gerald.baeza@...com>,
Loic Pallardy <loic.pallardy@...com>,
Linux ARM <linux-arm-kernel@...ts.infradead.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
DTML <devicetree@...r.kernel.org>,
"linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
<linux-stm32@...md-mailman.stormreply.com>
Subject: Re: [PATCH V4 02/25] mmc: mmci: create generic mmci_dma_setup
hi Ulf
On 10/03/2018 11:22 AM, Ulf Hansson wrote:
> + Srinivas
for next series, I will add Srinivas
>
> [...]
>
>> #ifdef CONFIG_DMA_ENGINE
>> -static void mmci_dma_setup(struct mmci_host *host)
>> +static inline void mmci_dma_release(struct mmci_host *host);
>> +
>> +int mmci_dmae_setup(struct mmci_host *host)
>> {
>> const char *rxname, *txname;
>>
>> @@ -464,8 +485,12 @@ static void mmci_dma_setup(struct mmci_host *host)
>> host->mmc->max_seg_size = max_seg_size;
>> }
>>
>> - if (host->ops && host->ops->dma_setup)
>> - host->ops->dma_setup(host);
>> + if (!host->dma_tx_channel || !host->dma_rx_channel) {
>> + mmci_dma_release(host);
>
> This doesn't look right to me. The existing code allows a tx channel
> to be used, even if an rx channel could not be setup. It seems
> reasonable to still allow that.
ok, I could replace by
if (!host->dma_tx_channel && !host->dma_rx_channel)
>
>> + return -EINVAL;
>> + }
>> +
>> + return 0;
>> }
>>
>> /*
>> @@ -496,7 +521,7 @@ static void mmci_dma_unmap(struct mmci_host *host, struct mmc_data *data)
>>
>> static void mmci_dma_data_error(struct mmci_host *host)
>> {
>> - if (!dma_inprogress(host))
>> + if (!host->use_dma || !dma_inprogress(host))
>
> Adding the check for use_dma here seems like an unnecessary check,
> unless there is a reason for it due to following changes on top. In
> such case, please make it a part of the patch(es) where it's actually
> needed.
In Fact, these checks are add to ensure the pio fallback, if only this
patch it's taken. In the next commit of serie, these checks are moved to
common functions mmci_dma_XX function.
>
>> return;
>>
>> dev_err(mmc_dev(host->mmc), "error during DMA transfer!\n");
>> @@ -514,7 +539,7 @@ static void mmci_dma_finalize(struct mmci_host *host, struct mmc_data *data)
>> u32 status;
>> int i;
>>
>> - if (!dma_inprogress(host))
>> + if (!host->use_dma || !dma_inprogress(host))
>
> Ditto.
>
>> return;
>>
>> /* Wait up to 1ms for the DMA to complete */
>> @@ -546,6 +571,7 @@ static void mmci_dma_finalize(struct mmci_host *host, struct mmc_data *data)
>> if (status & MCI_RXDATAAVLBLMASK) {
>> dev_err(mmc_dev(host->mmc), "buggy DMA detected. Taking evasive action.\n");
>> mmci_dma_release(host);
>> + host->use_dma = false;
>> }
>>
>> host->dma_in_progress = false;
>> @@ -640,6 +666,9 @@ static int mmci_dma_start_data(struct mmci_host *host, unsigned int datactrl)
>> int ret;
>> struct mmc_data *data = host->data;
>>
>> + if (!host->use_dma)
>> + return -EINVAL;
>> +
>> ret = mmci_dma_prep_data(host, host->data);
>> if (ret)
>> return ret;
>> @@ -674,6 +703,9 @@ static void mmci_get_next_data(struct mmci_host *host, struct mmc_data *data)
>> {
>> struct mmci_host_next *next = &host->next_data;
>>
>> + if (!host->use_dma)
>> + return;
>> +
>> WARN_ON(data->host_cookie && data->host_cookie != next->cookie);
>> WARN_ON(!data->host_cookie && (next->dma_desc || next->dma_chan));
>>
>> @@ -689,7 +721,7 @@ static void mmci_pre_request(struct mmc_host *mmc, struct mmc_request *mrq)
>> struct mmc_data *data = mrq->data;
>> struct mmci_host_next *nd = &host->next_data;
>>
>> - if (!data)
>> + if (!host->use_dma || !data)
>> return;
>>
>> BUG_ON(data->host_cookie);
>> @@ -707,7 +739,7 @@ static void mmci_post_request(struct mmc_host *mmc, struct mmc_request *mrq,
>> struct mmci_host *host = mmc_priv(mmc);
>> struct mmc_data *data = mrq->data;
>>
>> - if (!data || !data->host_cookie)
>> + if (!host->use_dma || !data || !data->host_cookie)
>
> Ditto.
>
>> return;
>>
>> mmci_dma_unmap(host, data);
>> @@ -735,14 +767,14 @@ static void mmci_post_request(struct mmc_host *mmc, struct mmc_request *mrq,
>> }
>> }
>>
>> +static struct mmci_host_ops mmci_variant_ops = {
>> + .dma_setup = mmci_dmae_setup,
>> +};
>> #else
>> /* Blank functions if the DMA engine is not available */
>> 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 void mmci_dma_release(struct mmci_host *host)
>> {
>> @@ -765,8 +797,14 @@ static inline int mmci_dma_start_data(struct mmci_host *host, unsigned int datac
>> #define mmci_pre_request NULL
>> #define mmci_post_request NULL
>>
>> +static struct mmci_host_ops mmci_variant_ops = {};
>
> This seems a bit unnecessary. See more about why, below.
>
>> #endif
>>
>> +void mmci_variant_init(struct mmci_host *host)
>
> Looks like you should make mmci_variant_init() internal to mmci.c,
> thus covert it to static.
>
> Moreover, I suggest you define a "static inline void
> mmci_variant_init()", when CONFIG_DMA_ENGINE is unset. In that way you
> don't need to assign host->ops at all for this case.
OK, no problem
>
>> +{
>> + host->ops = &mmci_variant_ops;
>> +}
>> +
>> static void mmci_start_data(struct mmci_host *host, struct mmc_data *data)
>> {
>> struct variant_data *variant = host->variant;
>> diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
>> index 01e6c6b..f7fe80f 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 {
>> @@ -323,6 +323,7 @@ struct mmci_host {
>> unsigned int size;
>> int (*get_rx_fifocnt)(struct mmci_host *h, u32 status, int remain);
>>
>> + u8 use_dma:1;
>> #ifdef CONFIG_DMA_ENGINE
>> /* DMA stuff */
>> struct dma_chan *dma_current;
>> @@ -336,3 +337,7 @@ struct mmci_host {
>> #endif
>> };
>>
>> +void mmci_variant_init(struct mmci_host *host);
>> +
>> +int mmci_dmae_setup(struct mmci_host *host);
>> +
>> diff --git a/drivers/mmc/host/mmci_qcom_dml.c b/drivers/mmc/host/mmci_qcom_dml.c
>> index be3fab5..c8d7592 100644
>> --- a/drivers/mmc/host/mmci_qcom_dml.c
>> +++ b/drivers/mmc/host/mmci_qcom_dml.c
>> @@ -119,19 +119,22 @@ 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;
>> int consumer_id, producer_id;
>> struct device_node *np = host->mmc->parent->of_node;
>>
>> + if (mmci_dmae_setup(host))
>> + return -EINVAL;
>> +
>> consumer_id = of_get_dml_pipe_index(np, "tx");
>> producer_id = of_get_dml_pipe_index(np, "rx");
>>
>> if (producer_id < 0 || consumer_id < 0) {
>> host->variant->qcom_dml = false;
>> - return;
>> + return -EINVAL;
>
> Seems like you need to call a corresponding dma release function here,
> before returning the error code.
>
> Probably an "mmci_dmae_release()" needs to be implemented as a part of
> this change - and then also called from here. This is according to
> Srinivas recommendations, which means falling back to pio. As a matter
> of fact this also needs to be clearly stated in the changelog, as you
> are really also improving the behavior for the Qcom variant.
it's in relation with the comment on
+ if (!host->dma_tx_channel || !host->dma_rx_channel) {
So yes.
At first sight Qcom need to have a tx and rx channel,
I will add mmci_dmae_release before returning error code.
>
> Unfortunate, I am not able to test this as I don't have the HW (which
> I thought I had). Perhaps Srinivas can help, once we have something
> ready for him to test.
>
>> }
>>
>> base = host->base + DML_OFFSET;
>> @@ -175,6 +178,8 @@ static void qcom_dma_setup(struct mmci_host *host)
>>
>> /* Make sure dml initialization is finished */
>> mb();
>> +
>> + return 0;
>> }
>>
>> static struct mmci_host_ops qcom_variant_ops = {
>> --
>> 2.7.4
>>
>
> Kind regards
> Uffe
>
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