[PATCH 08/14] mmc: s3cmci: handle highmem pages

Christoph Hellwig
2019-02-12T07:25:22Z

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@lst.de>
---
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..989fefea19f1 100644
--- a/drivers/mmc/host/s3cmci.c
+++ b/drivers/mmc/host/s3cmci.c
@@ -317,26 +317,17 @@ 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 +413,16 @@ 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 +431,12 @@ 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 +458,65 @@ 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 = (sg_kmap_atomic(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++;
}
}
+ sg_kunmap_atomic(host->cur_sg, 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 +533,20 @@ static void do_pio_write(struct s3cmci_host *host)
host->pio_count += fifo;

fifo = (fifo + 3) >> 2;
- ptr = host->pio_ptr;
- while (fifo--)
+ buf = (sg_kmap_atomic(host->cur_sg) + host->pio_offset);
+ ptr = buf;
+ while (fifo--) {
writel(*ptr++, to_ptr);
- host->pio_ptr = ptr;
+ host->pio_offset += 4;
+ }
+ sg_kunmap_atomic(host->cur_sg, 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 +1052,7 @@ 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;
@@ -1678,6 +1676,7 @@ static int s3cmci_probe(struct platform_device *pdev)
host->clk_rate = clk_get_rate(host->clk);

mmc->ops = &s3cmci_ops;
+ mmc->need_kmap = 1;
mmc->ocr_avail = MMC_VDD_32_33 | MMC_VDD_33_34;
#ifdef CONFIG_MMC_S3C_HW_SDIO_IRQ
mmc->caps = MMC_CAP_4_BIT_DATA | MMC_CAP_SDIO_IRQ;
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