[PATCH 04/14] mmc: davinci: handle highmem pages

Christoph Hellwig
2019-02-12T07:25:18Z

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 | 22 +++++++++++++---------
1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/drivers/mmc/host/davinci_mmc.c b/drivers/mmc/host/davinci_mmc.c
index 9e68c3645e22..6a16d7a1d5bc 100644
--- a/drivers/mmc/host/davinci_mmc.c
+++ b/drivers/mmc/host/davinci_mmc.c
@@ -194,11 +194,12 @@ 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 +230,8 @@ 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 +239,7 @@ 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;
+ u8 *p, *base;
unsigned int i;

if (host->buffer_bytes_left == 0) {
@@ -246,7 +247,8 @@ static void davinci_fifo_data_trans(struct mmc_davinci_host *host,
mmc_davinci_sg_to_buf(host);
}

- p = host->buffer;
+ base = sg_kmap_atomic(host->sg);
+ p = base + host->buffer_offset;
if (n > host->buffer_bytes_left)
n = host->buffer_bytes_left;
host->buffer_bytes_left -= n;
@@ -275,7 +277,8 @@ static void davinci_fifo_data_trans(struct mmc_davinci_host *host,
p = p + (n & 3);
}
}
- host->buffer = p;
+ host->buffer_offset = p - base;
+ sg_kunmap_atomic(host->sg, base);
}

static void mmc_davinci_start_command(struct mmc_davinci_host *host,
@@ -572,7 +575,7 @@ 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
@@ -1291,6 +1294,7 @@ static int davinci_mmcsd_probe(struct platform_device *pdev)

mmc->ops = &mmc_davinci_ops;
mmc->ocr_avail = MMC_VDD_32_33 | MMC_VDD_33_34;
+ mmc->need_kmap = 1;

/* With no iommu coalescing pages, each phys_seg is a hw_seg.
* Each hw_seg uses one EDMA parameter RAM slot, always one
--
2.20.1