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Subject[PATCH 01/11] mmc: davinci: handle highmem pages
Date
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/davinci_mmc.c | 43 ++++++++++++++++++++--------------
1 file changed, 26 insertions(+), 17 deletions(-)

diff --git a/drivers/mmc/host/davinci_mmc.c b/drivers/mmc/host/davinci_mmc.c
index 9e68c3645e22..9c500c52b63d 100644
--- a/drivers/mmc/host/davinci_mmc.c
+++ b/drivers/mmc/host/davinci_mmc.c
@@ -26,6 +26,7 @@
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/cpufreq.h>
+#include <linux/highmem.h>
#include <linux/mmc/host.h>
#include <linux/io.h>
#include <linux/irq.h>
@@ -194,11 +195,12 @@ struct mmc_davinci_host {
#define DAVINCI_MMC_DATADIR_WRITE 2
unsigned char data_dir;

- /* buffer is used during PIO of one scatterlist segment, and
- * is updated along with buffer_bytes_left. bytes_left applies
- * to all N blocks of the PIO transfer.
+ /*
+ * buffer_offset is used during PIO of one scatterlist segment, and is
+ * updated along with buffer_bytes_left. bytes_left applies to all N
+ * blocks of the PIO transfer.
*/
- u8 *buffer;
+ u32 buffer_offset;
u32 buffer_bytes_left;
u32 bytes_left;

@@ -229,8 +231,8 @@ static irqreturn_t mmc_davinci_irq(int irq, void *dev_id);
/* PIO only */
static void mmc_davinci_sg_to_buf(struct mmc_davinci_host *host)
{
+ host->buffer_offset = host->sg->offset;
host->buffer_bytes_left = sg_dma_len(host->sg);
- host->buffer = sg_virt(host->sg);
if (host->buffer_bytes_left > host->bytes_left)
host->buffer_bytes_left = host->bytes_left;
}
@@ -238,7 +240,7 @@ static void mmc_davinci_sg_to_buf(struct mmc_davinci_host *host)
static void davinci_fifo_data_trans(struct mmc_davinci_host *host,
unsigned int n)
{
- u8 *p;
+ void *p;
unsigned int i;

if (host->buffer_bytes_left == 0) {
@@ -246,7 +248,7 @@ static void davinci_fifo_data_trans(struct mmc_davinci_host *host,
mmc_davinci_sg_to_buf(host);
}

- p = host->buffer;
+ p = kmap_atomic(sg_page(host->sg));
if (n > host->buffer_bytes_left)
n = host->buffer_bytes_left;
host->buffer_bytes_left -= n;
@@ -258,24 +260,31 @@ static void davinci_fifo_data_trans(struct mmc_davinci_host *host,
*/
if (host->data_dir == DAVINCI_MMC_DATADIR_WRITE) {
for (i = 0; i < (n >> 2); i++) {
- writel(*((u32 *)p), host->base + DAVINCI_MMCDXR);
- p = p + 4;
+ u32 *val = p + host->buffer_offset;
+
+ writel(*val, host->base + DAVINCI_MMCDXR);
+ host->buffer_offset += 4;
}
if (n & 3) {
- iowrite8_rep(host->base + DAVINCI_MMCDXR, p, (n & 3));
- p = p + (n & 3);
+ iowrite8_rep(host->base + DAVINCI_MMCDXR,
+ p + host->buffer_offset, n & 3);
+ host->buffer_offset += (n & 3);
}
} else {
for (i = 0; i < (n >> 2); i++) {
- *((u32 *)p) = readl(host->base + DAVINCI_MMCDRR);
- p = p + 4;
+ u32 *val = p + host->buffer_offset;
+
+ *val = readl(host->base + DAVINCI_MMCDRR);
+ host->buffer_offset += 4;
}
if (n & 3) {
- ioread8_rep(host->base + DAVINCI_MMCDRR, p, (n & 3));
- p = p + (n & 3);
+ ioread8_rep(host->base + DAVINCI_MMCDRR,
+ p + host->buffer_offset, n & 3);
+ host->buffer_offset += (n & 3);
}
}
- host->buffer = p;
+
+ kunmap_atomic(p);
}

static void mmc_davinci_start_command(struct mmc_davinci_host *host,
@@ -572,7 +581,7 @@ mmc_davinci_prepare_data(struct mmc_davinci_host *host, struct mmc_request *req)
host->base + DAVINCI_MMCFIFOCTL);
}

- host->buffer = NULL;
+ host->buffer_offset = 0;
host->bytes_left = data->blocks * data->blksz;

/* For now we try to use DMA whenever we won't need partial FIFO
--
2.20.1
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