On Mon, 14 Jan 2019 at 10:58, Christoph Hellwig wrote:
>
> Instead of setting up a kernel pointer to track the current PIO address,
> track the offset in the current page, and do an atomic kmap for the page
> while doing the actual PIO operations.
>
> Signed-off-by: Christoph Hellwig
Nitpick: This one have some trailing whitespace errors, which git
complains about when I apply it.
No need to re-spin due to this, I can fix it up.
Kind regards
Uffe
> ---
> drivers/mmc/host/s3cmci.c | 107 +++---
> drivers/mmc/host/s3cmci.h | 3 +-
> 2 files changed, 55 insertions(+), 55 deletions(-)
>
> diff --git a/drivers/mmc/host/s3cmci.c b/drivers/mmc/host/s3cmci.c
> index 10f5219b3b40..1be84426c817 100644
> --- a/drivers/mmc/host/s3cmci.c
> +++ b/drivers/mmc/host/s3cmci.c
> @@ -15,6 +15,7 @@
> #include
> #include
> #include
> +#include
> #include
> #include
> #include
> @@ -317,26 +318,17 @@ static void s3cmci_check_sdio_irq(struct s3cmci_host
> *host)
> }
> }
>
> -static inline int get_data_buffer(struct s3cmci_host *host,
> - u32 *bytes, u32 **pointer)
> +static inline int get_data_buffer(struct s3cmci_host *host)
> {
> - struct scatterlist *sg;
> -
> - if (host->pio_active == XFER_NONE)
> - return -EINVAL;
> -
> - if ((!host->mrq) || (!host->mrq->data))
> - return -EINVAL;
> -
> if (host->pio_sgptr >= host->mrq->data->sg_len) {
> dbg(host, dbg_debug, "no more buffers (%i/%i)\n",
> host->pio_sgptr, host->mrq->data->sg_len);
> return -EBUSY;
> }
> - sg = >mrq->data->sg[host->pio_sgptr];
> + host->cur_sg = >mrq->data->sg[host->pio_sgptr];
>
> - *bytes = sg->length;
> - *pointer = sg_virt(sg);
> + host->pio_bytes = host->cur_sg->length;
> + host->pio_offset = host->cur_sg->offset;
>
> host->pio_sgptr++;
>
> @@ -422,11 +414,16 @@ static void s3cmci_disable_irq(struct s3cmci_host
> *host, bool transfer)
>
> static void do_pio_read(struct s3cmci_host *host)
> {
> - int res;
> u32 fifo;
> u32 *ptr;
> u32 fifo_words;
> void __iomem *from_ptr;
> + void *buf;
> +
> + if (host->pio_active == XFER_NONE)
> + goto done;
> + if (!host->mrq || !host->mrq->data)
> + goto done;
>
> /* write real prescaler to host, it might be set slow to fix */
> writel(host->prescaler, host->base + S3C2410_SDIPRE);
> @@ -435,20 +432,12 @@ static void do_pio_read(struct s3cmci_host *host)
>
> while ((fifo = fifo_count(host))) {
> if (!host->pio_bytes) {
> - res = get_data_buffer(host, >pio_bytes,
> - >pio_ptr);
> - if (res) {
> - host->pio_active = XFER_NONE;
> - host->complete_what = COMPLETION_FINALIZE;
> -
> - dbg(host, dbg_pio, "pio_read(): "
> - "complete (no more data).\n");
> - return;
> - }
> + if (get_data_buffer(host) < 0)
> + goto done;
>
> dbg(host, dbg_pio,
> - "pio_read(): new target: [%i]@[%p]\n",
> - host->pio_bytes, host->pio_ptr);
> + "pio_read(): new target: [%i]@[%zu]\n",
> + host->pio_bytes, host->pio_offset);
> }
>
> dbg(host, dbg_pio,
> @@ -470,63 +459,65 @@ static void do_pio_read(struct s3cmci_host *host)
> host->pio_count += fifo;
>
> fifo_words = fifo >> 2;
> - ptr = host->pio_ptr;
> - while (fifo_words--)
> +
> + buf = (kmap_atomic(sg_page(host->cur_sg)) + host->pio_offset);
> + ptr = buf;
> + while (fifo_words--) {
> *ptr++ = readl(from_ptr);
> - host->pio_ptr = ptr;
> + host->pio_offset += 4;
> + }
>
> if (fifo & 3) {
> u32 n = fifo & 3;
> u32 data = readl(from_ptr);
> - u8 *p = (u8 *)host->pio_ptr;
> + u8 *p = (u8 *)ptr;
>
> while (n--) {
> *p++ = data;
> data >>= 8;
> + host->pio_offset++;
> }
> }
> + kunmap_atomic(buf);
> }
>
> if (!host->pio_bytes) {
> - res = get_data_buffer(host, >pio_bytes, >pio_ptr);
> - if (res) {
> - dbg(host, dbg_pio,
> -
