Re: [PATCH V2 03/27] mmc: mmci: convert dma_setup callback to return an int
From: Ulf Hansson
Date: Mon Sep 24 2018 - 10:28:51 EST
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.
> + 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.
> - return;
> + return -EINVAL;
My point is, if you return an error code here, it means that the error
code becomes propagated and ->probe() will fail.
Ideally, we should be able fall back to pio mode when dma doesn't
work. I have looped in Srinivas who implemented the qcom dml support,
let's see if he can explains the intent with the code.
I also volunteer to help out running some tests on the 410c platform,
however allow me a day or two to do that.
> }
>
> base = host->base + DML_OFFSET;
> @@ -175,6 +175,8 @@ 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