Hi Guennadi, could you resend this one with some style changes:
On Tue, Nov 23, 2010 at 05:24:15PM +0100, Guennadi Liakhovetski wrote:
> For example, with SDIO WLAN cards, some transfers happen with buffers at odd
> addresses, whereas the SH-Mobile DMA engine requires even addresses for SDHI.
> This patch extends the tmio driver with a bounce buffer, that is used for
> single entry scatter-gather lists both for sending and receiving. If we ever
> encounter unaligned transfers with multi-element sg lists, this patch will have
> to be extended. For now it just falls back to PIO in this and other unsupported
> cases.
>
> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
Please wrap commit messages at 72 cols, not 80.
> ---
> drivers/mmc/host/tmio_mmc.c | 81 +++++++++++++++++++++++++++++++++++++++----
> include/linux/mfd/tmio.h | 1 +
> 2 files changed, 75 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/mmc/host/tmio_mmc.c b/drivers/mmc/host/tmio_mmc.c
> index 118ad86..57ece9d 100644
> --- a/drivers/mmc/host/tmio_mmc.c
> +++ b/drivers/mmc/host/tmio_mmc.c
> @@ -111,6 +111,8 @@
> sd_ctrl_write32((host), CTL_STATUS, ~(i)); \
> } while (0)
>
> +/* This is arbitrary, just noone needed any higher alignment yet */
> +#define MAX_ALIGN 4
>
> struct tmio_mmc_host {
> void __iomem *ctl;
> @@ -127,6 +129,7 @@ struct tmio_mmc_host {
>
> /* pio related stuff */
> struct scatterlist *sg_ptr;
> + struct scatterlist *sg_orig;
> unsigned int sg_len;
> unsigned int sg_off;
>
> @@ -139,6 +142,8 @@ struct tmio_mmc_host {
> struct tasklet_struct dma_issue;
> #ifdef CONFIG_TMIO_MMC_DMA
> unsigned int dma_sglen;
> + u8 bounce_buf[PAGE_CACHE_SIZE] __attribute__((aligned(MAX_ALIGN)));
> + struct scatterlist bounce_sg;
> #endif
> };
>
> @@ -180,6 +185,7 @@ static void tmio_mmc_init_sg(struct tmio_mmc_host *host, struct mmc_data *data)
> {
> host->sg_len = data->sg_len;
> host->sg_ptr = data->sg;
> + host->sg_orig = data->sg;
> host->sg_off = 0;
> }
>
> @@ -436,8 +442,14 @@ static void tmio_mmc_do_data_irq(struct tmio_mmc_host *host)
> */
>
> if (data->flags & MMC_DATA_READ) {
> - if (!host->chan_rx)
> + if (!host->chan_rx) {
> disable_mmc_irqs(host, TMIO_MASK_READOP);
> + } else if (host->sg_ptr == &host->bounce_sg) {
> + unsigned long flags;
> + void *sg_vaddr = tmio_mmc_kmap_atomic(host->sg_orig, &flags);
Would be nice to stay within 80-chars where possible.
> + memcpy(sg_vaddr, host->bounce_buf, host->bounce_sg.length);
> + tmio_mmc_kunmap_atomic(sg_vaddr, &flags);
> + }
> dev_dbg(&host->pdev->dev, "Complete Rx request %p\n",
> host->mrq);
> } else {
> @@ -529,8 +541,7 @@ static void tmio_mmc_cmd_irq(struct tmio_mmc_host *host,
> if (!host->chan_rx)
> enable_mmc_irqs(host, TMIO_MASK_READOP);
> } else {
> - struct dma_chan *chan = host->chan_tx;
> - if (!chan)
> + if (!host->chan_tx)
> enable_mmc_irqs(host, TMIO_MASK_WRITEOP);
> else
> tasklet_schedule(&host->dma_issue);
> @@ -634,11 +645,36 @@ static void tmio_dma_complete(void *arg)
>
> static void tmio_mmc_start_dma_rx(struct tmio_mmc_host *host)
> {
> - struct scatterlist *sg = host->sg_ptr;
> + struct scatterlist *sg = host->sg_ptr, *sg_tmp;
> struct dma_async_tx_descriptor *desc = NULL;
> struct dma_chan *chan = host->chan_rx;
> + struct mfd_cell *cell = host->pdev->dev.platform_data;
> + struct tmio_mmc_data *pdata = cell->driver_data;
> dma_cookie_t cookie;
> - int ret;
> + int ret, i;
> + bool aligned = true, multiple = true;
> + unsigned int align = (1 << pdata->dma->alignment_shift) - 1;
> +
> + for_each_sg(sg, sg_tmp, host->sg_len, i) {
> + if (sg_tmp->offset & align)
> + aligned = false;
> + if (sg_tmp->length & align) {
> + multiple = false;
> + break;
> + }
> + }
> +
> + if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
> + align >= MAX_ALIGN)) || !multiple)
> + goto pio;
> +
> + /* The only sg element can be unaligned, use our bounce buffer then */
> + if (!aligned) {
> + /* The first sg element unaligned, use our bounce-buffer */
> + sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
> + host->sg_ptr = &host->bounce_sg;
> + sg = host->sg_ptr;
> + }
The second comment is missing a verb, and looks redundant with the first.
>
> ret = dma_map_sg(&host->pdev->dev, sg, host->sg_len, DMA_FROM_DEVICE);
> if (ret > 0) {
> @@ -661,6 +697,7 @@ static void tmio_mmc_start_dma_rx(struct tmio_mmc_host *host)
> dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",
> __func__, host->sg_len, ret, cookie, host->mrq);
>
> +pio:
> if (!desc) {
> /* DMA failed, fall back to PIO */
> if (ret >= 0)
> @@ -684,11 +721,40 @@ static void tmio_mmc_start_dma_rx(struct tmio_mmc_host *host)
>
> static void tmio_mmc_start_dma_tx(struct tmio_mmc_host *host)
> {
> - struct scatterlist *sg = host->sg_ptr;
> + struct scatterlist *sg = host->sg_ptr, *sg_tmp;
> struct dma_async_tx_descriptor *desc = NULL;
> struct dma_chan *chan = host->chan_tx;
> + struct mfd_cell *cell = host->pdev->dev.platform_data;
> + struct tmio_mmc_data *pdata = cell->driver_data;
> dma_cookie_t cookie;
> - int ret;
> + int ret, i;
> + bool aligned = true, multiple = true;
> + unsigned int align = (1 << pdata->dma->alignment_shift) - 1;
> +
> + for_each_sg(sg, sg_tmp, host->sg_len, i) {
> + if (sg_tmp->offset & align)
> + aligned = false;
> + if (sg_tmp->length & align) {
> + multiple = false;
> + break;
> + }
> + }
> +
> + if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
> + align >= MAX_ALIGN)) || !multiple)
> + goto pio;
> +
> + /* The only sg element can be unaligned, use our bounce buffer then */
> + if (!aligned) {
> + unsigned long flags;
> + void *sg_vaddr = tmio_mmc_kmap_atomic(sg, &flags);
> + /* The first sg element unaligned, use our bounce-buffer */
> + sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
> + memcpy(host->bounce_buf, sg_vaddr, host->bounce_sg.length);
> + tmio_mmc_kunmap_atomic(sg_vaddr, &flags);
> + host->sg_ptr = &host->bounce_sg;
> + sg = host->sg_ptr;
> + }
Same here.
>
> ret = dma_map_sg(&host->pdev->dev, sg, host->sg_len, DMA_TO_DEVICE);
> if (ret > 0) {
> @@ -709,6 +775,7 @@ static void tmio_mmc_start_dma_tx(struct tmio_mmc_host *host)
> dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",
> __func__, host->sg_len, ret, cookie, host->mrq);
>
> +pio:
> if (!desc) {
> /* DMA failed, fall back to PIO */
> if (ret >= 0)
> diff --git a/include/linux/mfd/tmio.h b/include/linux/mfd/tmio.h
> index 085f041..dbfc053 100644
> --- a/include/linux/mfd/tmio.h
> +++ b/include/linux/mfd/tmio.h
> @@ -66,6 +66,7 @@ void tmio_core_mmc_clk_div(void __iomem *cnf, int shift, int state);
> struct tmio_mmc_dma {
> void *chan_priv_tx;
> void *chan_priv_rx;
> + int alignment_shift;
> };
>
> /*
Thanks,
--
Chris Ball <cjb@xxxxxxxxxx> <http://printf.net/>
One Laptop Per Child
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