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Message-ID: <CAPDyKFoJfUyMi7oFo2pkxfEUTerNSBwHvJOB2d22xoPL4RTQUA@mail.gmail.com>
Date: Mon, 15 Oct 2018 15:15:38 +0200
From: Ulf Hansson <ulf.hansson@...aro.org>
To: Masahiro Yamada <yamada.masahiro@...ionext.com>
Cc: "linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
Wolfram Sang <wsa+renesas@...g-engineering.com>,
Linux-Renesas <linux-renesas-soc@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Linux ARM <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH] mmc: tmio: simplify the DMA mode test
On 12 October 2018 at 17:03, Masahiro Yamada
<yamada.masahiro@...ionext.com> wrote:
> host->chan_{rx,tx} represents the DMA capability of the platform.
> Even if DMA is supported, there are cases where we want to use PIO,
> for example, data length is short enough as commit 5f52c3552946
> ("mmc: tmio: use PIO for short transfers") mentioned.
>
> Regarding the hardware control flow, we are interested in whether DMA
> is currently enabled or not, instead of whether the platform has the
> DMA capability.
>
> Hence, the several conditionals in tmio_mmc_core.c end up with
> checking host->chan_{rx,tx} and !host->force_pio. This is not nice.
>
> Let's flip the flag host->force_pio into host->dma_on.
>
> host->dma_on represents whether the DMA is currently enabled or not.
> This flag is set false in the beginning of each command, then should
> be set true by tmio_mmc_start_dma() when the DMA is turned on.
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com>
Applied for next, thanks!
Kind regards
Uffe
> ---
>
> drivers/mmc/host/renesas_sdhi_internal_dmac.c | 3 ++-
> drivers/mmc/host/renesas_sdhi_sys_dmac.c | 10 ++++------
> drivers/mmc/host/tmio_mmc.h | 2 +-
> drivers/mmc/host/tmio_mmc_core.c | 14 +++++++-------
> drivers/mmc/host/uniphier-sd.c | 6 ++++--
> 5 files changed, 18 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/mmc/host/renesas_sdhi_internal_dmac.c b/drivers/mmc/host/renesas_sdhi_internal_dmac.c
> index ca0b439..885676b 100644
> --- a/drivers/mmc/host/renesas_sdhi_internal_dmac.c
> +++ b/drivers/mmc/host/renesas_sdhi_internal_dmac.c
> @@ -201,13 +201,14 @@ renesas_sdhi_internal_dmac_start_dma(struct tmio_mmc_host *host,
> renesas_sdhi_internal_dmac_dm_write(host, DM_DTRAN_ADDR,
> sg_dma_address(sg));
>
> + host->dma_on = true;
> +
> return;
>
> force_pio_with_unmap:
> dma_unmap_sg(&host->pdev->dev, sg, host->sg_len, mmc_get_dma_dir(data));
>
> force_pio:
> - host->force_pio = true;
> renesas_sdhi_internal_dmac_enable_dma(host, false);
> }
>
> diff --git a/drivers/mmc/host/renesas_sdhi_sys_dmac.c b/drivers/mmc/host/renesas_sdhi_sys_dmac.c
> index 5389c48..3c97831 100644
> --- a/drivers/mmc/host/renesas_sdhi_sys_dmac.c
> +++ b/drivers/mmc/host/renesas_sdhi_sys_dmac.c
> @@ -213,10 +213,8 @@ static void renesas_sdhi_sys_dmac_start_dma_rx(struct tmio_mmc_host *host)
> goto pio;
> }
>
> - if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
> - host->force_pio = true;
> + if (sg->length < TMIO_MMC_MIN_DMA_LEN)
> return;
> - }
>
> /* The only sg element can be unaligned, use our bounce buffer then */
> if (!aligned) {
> @@ -240,6 +238,7 @@ static void renesas_sdhi_sys_dmac_start_dma_rx(struct tmio_mmc_host *host)
> desc = NULL;
> ret = cookie;
> }
> + host->dma_on = true;
> }
> pio:
> if (!desc) {
> @@ -286,10 +285,8 @@ static void renesas_sdhi_sys_dmac_start_dma_tx(struct tmio_mmc_host *host)
> goto pio;
> }
>
> - if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
> - host->force_pio = true;
> + if (sg->length < TMIO_MMC_MIN_DMA_LEN)
> return;
> - }
>
> /* The only sg element can be unaligned, use our bounce buffer then */
> if (!aligned) {
> @@ -318,6 +315,7 @@ static void renesas_sdhi_sys_dmac_start_dma_tx(struct tmio_mmc_host *host)
> desc = NULL;
> ret = cookie;
> }
> + host->dma_on = true;
> }
> pio:
> if (!desc) {
> diff --git a/drivers/mmc/host/tmio_mmc.h b/drivers/mmc/host/tmio_mmc.h
> index 18b4308..1c3bdad 100644
> --- a/drivers/mmc/host/tmio_mmc.h
> +++ b/drivers/mmc/host/tmio_mmc.h
> @@ -142,7 +142,7 @@ struct tmio_mmc_host {
> struct tmio_mmc_data *pdata;
>
> /* DMA support */
> - bool force_pio;
> + bool dma_on;
> struct dma_chan *chan_rx;
> struct dma_chan *chan_tx;
> struct tasklet_struct dma_issue;
> diff --git a/drivers/mmc/host/tmio_mmc_core.c b/drivers/mmc/host/tmio_mmc_core.c
> index a571106..38be3fc 100644
> --- a/drivers/mmc/host/tmio_mmc_core.c
> +++ b/drivers/mmc/host/tmio_mmc_core.c
> @@ -364,7 +364,7 @@ static void tmio_mmc_pio_irq(struct tmio_mmc_host *host)
> unsigned int count;
> unsigned long flags;
>
> - if ((host->chan_tx || host->chan_rx) && !host->force_pio) {
> + if (host->dma_on) {
> pr_err("PIO IRQ in DMA mode!\n");
> return;
> } else if (!data) {
> @@ -436,7 +436,7 @@ void tmio_mmc_do_data_irq(struct tmio_mmc_host *host)
> */
>
> if (data->flags & MMC_DATA_READ) {
> - if (host->chan_rx && !host->force_pio)
> + if (host->dma_on)
> tmio_mmc_check_bounce_buffer(host);
> dev_dbg(&host->pdev->dev, "Complete Rx request %p\n",
> host->mrq);
> @@ -473,7 +473,7 @@ static void tmio_mmc_data_irq(struct tmio_mmc_host *host, unsigned int stat)
> if (stat & TMIO_STAT_CRCFAIL || stat & TMIO_STAT_STOPBIT_ERR ||
> stat & TMIO_STAT_TXUNDERRUN)
> data->error = -EILSEQ;
> - if (host->chan_tx && (data->flags & MMC_DATA_WRITE) && !host->force_pio) {
> + if (host->dma_on && (data->flags & MMC_DATA_WRITE)) {
> u32 status = sd_ctrl_read16_and_16_as_32(host, CTL_STATUS);
> bool done = false;
>
> @@ -497,7 +497,7 @@ static void tmio_mmc_data_irq(struct tmio_mmc_host *host, unsigned int stat)
> tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_DATAEND);
> tmio_mmc_dataend_dma(host);
> }
> - } else if (host->chan_rx && (data->flags & MMC_DATA_READ) && !host->force_pio) {
> + } else if (host->dma_on && (data->flags & MMC_DATA_READ)) {
> tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_DATAEND);
> tmio_mmc_dataend_dma(host);
> } else {
> @@ -550,7 +550,7 @@ static void tmio_mmc_cmd_irq(struct tmio_mmc_host *host, unsigned int stat)
> */
> if (host->data && (!cmd->error || cmd->error == -EILSEQ)) {
> if (host->data->flags & MMC_DATA_READ) {
> - if (host->force_pio || !host->chan_rx) {
> + if (!host->dma_on) {
> tmio_mmc_enable_mmc_irqs(host, TMIO_MASK_READOP);
> } else {
> tmio_mmc_disable_mmc_irqs(host,
> @@ -558,7 +558,7 @@ static void tmio_mmc_cmd_irq(struct tmio_mmc_host *host, unsigned int stat)
> tasklet_schedule(&host->dma_issue);
> }
> } else {
> - if (host->force_pio || !host->chan_tx) {
> + if (!host->dma_on) {
> tmio_mmc_enable_mmc_irqs(host, TMIO_MASK_WRITEOP);
> } else {
> tmio_mmc_disable_mmc_irqs(host,
> @@ -688,7 +688,7 @@ static int tmio_mmc_start_data(struct tmio_mmc_host *host,
>
> tmio_mmc_init_sg(host, data);
> host->data = data;
> - host->force_pio = false;
> + host->dma_on = false;
>
> /* Set transfer length / blocksize */
> sd_ctrl_write16(host, CTL_SD_XFER_LEN, data->blksz);
> diff --git a/drivers/mmc/host/uniphier-sd.c b/drivers/mmc/host/uniphier-sd.c
> index 1ee9fd0..91a2be4 100644
> --- a/drivers/mmc/host/uniphier-sd.c
> +++ b/drivers/mmc/host/uniphier-sd.c
> @@ -157,13 +157,14 @@ static void uniphier_sd_external_dma_start(struct tmio_mmc_host *host,
> if (cookie < 0)
> goto unmap_sg;
>
> + host->dma_on = true;
> +
> return;
>
> unmap_sg:
> dma_unmap_sg(mmc_dev(host->mmc), host->sg_ptr, host->sg_len,
> priv->dma_dir);
> force_pio:
> - host->force_pio = true;
> uniphier_sd_dma_endisable(host, 0);
> }
>
> @@ -283,9 +284,10 @@ static void uniphier_sd_internal_dma_start(struct tmio_mmc_host *host,
> writel(lower_32_bits(dma_addr), host->ctl + UNIPHIER_SD_DMA_ADDR_L);
> writel(upper_32_bits(dma_addr), host->ctl + UNIPHIER_SD_DMA_ADDR_H);
>
> + host->dma_on = true;
> +
> return;
> force_pio:
> - host->force_pio = true;
> uniphier_sd_dma_endisable(host, 0);
> }
>
> --
> 2.7.4
>
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