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Date: Wed, 3 Oct 2018 11:22:00 +0200
From: Ulf Hansson <ulf.hansson@...aro.org>
To: Ludovic Barre <ludovic.Barre@...com>
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
+ 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.
> + 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.
> 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.
> +{
> + 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.
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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