Re: [PATCH 05/11] mmc: s3cmci: handle highmem pages

From: Ulf Hansson
Date: Wed Jan 30 2019 - 02:58:26 EST

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On Mon, 14 Jan 2019 at 10:58, Christoph Hellwig <hch@xxxxxx> 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 <hch@xxxxxx>

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 <linux/dmaengine.h>
> #include <linux/dma-mapping.h>
> #include <linux/clk.h>
> +#include <linux/highmem.h>
> #include <linux/mmc/host.h>
> #include <linux/platform_device.h>
> #include <linux/cpufreq.h>
> @@ -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 = &host->mrq->data->sg[host->pio_sgptr];
> + host->cur_sg = &host->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, &host->pio_bytes,
> - &host->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, &host->pio_bytes, &host->pio_ptr);
> - if (res) {
> - dbg(host, dbg_pio,
> - "pio_read(): complete (no more buffers).\n");
> - host->pio_active = XFER_NONE;
> - host->complete_what = COMPLETION_FINALIZE;
> -
> - return;
> - }
> + if (get_data_buffer(host) < 0)
> + goto done;
> }
>
> enable_imask(host,
> S3C2410_SDIIMSK_RXFIFOHALF | S3C2410_SDIIMSK_RXFIFOLAST);
> + return;
> +
> +done:
> + host->pio_active = XFER_NONE;
> + host->complete_what = COMPLETION_FINALIZE;
> + dbg(host, dbg_pio, "pio_read(): complete (no more data).\n");
> }
>
> static void do_pio_write(struct s3cmci_host *host)
> {
> void __iomem *to_ptr;
> - int res;
> + void *buf;
> u32 fifo;
> u32 *ptr;
>
> + if (host->pio_active == XFER_NONE)
> + goto done;
> + if (!host->mrq || !host->mrq->data)
> + goto done;
> +
> to_ptr = host->base + host->sdidata;
>
> while ((fifo = fifo_free(host)) > 3) {
> if (!host->pio_bytes) {
> - res = get_data_buffer(host, &host->pio_bytes,
> - &host->pio_ptr);
> - if (res) {
> - dbg(host, dbg_pio,
> - "pio_write(): complete (no more data).\n");
> - host->pio_active = XFER_NONE;
> -
> - return;
> - }
> + if (get_data_buffer(host) < 0)
> + goto done;
>
> dbg(host, dbg_pio,
> - "pio_write(): new source: [%i]@[%p]\n",
> - host->pio_bytes, host->pio_ptr);
> + "pio_write(): new source: [%i]@[%zd]\n",
> + host->pio_bytes, host->pio_offset);
>
> }
>
> @@ -543,13 +534,20 @@ static void do_pio_write(struct s3cmci_host *host)
> host->pio_count += fifo;
>
> fifo = (fifo + 3) >> 2;
> - ptr = host->pio_ptr;
> - while (fifo--)
> + buf = (kmap_atomic(sg_page(host->cur_sg)) + host->pio_offset);
> + ptr = buf;
> + while (fifo--) {
> writel(*ptr++, to_ptr);
> - host->pio_ptr = ptr;
> + host->pio_offset += 4;
> + }
> + kunmap_atomic(buf);
> }
>
> enable_imask(host, S3C2410_SDIIMSK_TXFIFOHALF);
> + return;
> +done:
> + dbg(host, dbg_pio, "pio_write(): complete (no more data).\n");
> + host->pio_active = XFER_NONE;
> }
>
> static void pio_tasklet(unsigned long data)
> @@ -1055,6 +1053,7 @@ static int s3cmci_prepare_pio(struct s3cmci_host *host, struct mmc_data *data)
> BUG_ON((data->flags & BOTH_DIR) == BOTH_DIR);
>
> host->pio_sgptr = 0;
> + host->cur_sg = &host->mrq->data->sg[host->pio_sgptr];
> host->pio_bytes = 0;
> host->pio_count = 0;
> host->pio_active = rw ? XFER_WRITE : XFER_READ;
> diff --git a/drivers/mmc/host/s3cmci.h b/drivers/mmc/host/s3cmci.h
> index 30c2c0dd1bc8..4320f7d832dc 100644
> --- a/drivers/mmc/host/s3cmci.h
> +++ b/drivers/mmc/host/s3cmci.h
> @@ -50,10 +50,11 @@ struct s3cmci_host {
>
> int dma_complete;
>
> + struct scatterlist *cur_sg;
> u32 pio_sgptr;
> u32 pio_bytes;
> u32 pio_count;
> - u32 *pio_ptr;
> + u32 pio_offset;
> #define XFER_NONE 0
> #define XFER_READ 1
> #define XFER_WRITE 2
> --
> 2.20.1
>

Next message: Christoph Hellwig: "Re: [RFC PATCH 3/5] mm/vma: add support for peer to peer to device vma"
Previous message: Kees Cook: "Re: [PATCH] lib: zstd: Mark expected switch fall-throughs"
Next in thread: Christoph Hellwig: "Re: [PATCH 05/11] mmc: s3cmci: handle highmem pages"
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