From: Ulf Hansson <ulf.hans...@stericsson.com>
Earlier code in pio_write was expecting that each
scatter-gather buffer was 4-bytes aligned which is
not always the case, especially when dealing with long
chains of SDIO packages. This patch fix the problem by
using a 4 bytes buffer to cache unaligned data between
each unaligned pio_write operation.
In the last transaction we pad the last write access
with zeroes.
Remove older fix for ST Micro since it was not a
variant-specific problem.
Signed-off-by: Ulf Hansson <ulf.hans...@stericsson.com>
Reviewed-by: Henrik Carling <henrik.carl...@stericsson.com>
Signed-off-by: Dmitry Tarnyagin <dmitry.tarnya...@stericsson.com>
[Minor fixups like making the cache word a u32]
Signed-off-by: Linus Walleij <linus.wall...@linaro.org>
---
drivers/mmc/host/mmci.c | 106 ++++++++++++++++++++++++++++++++++------------
drivers/mmc/host/mmci.h | 3 +
2 files changed, 81 insertions(+), 28 deletions(-)
diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index 93dcd2a..81aac79 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -533,6 +533,8 @@ static void mmci_start_data(struct mmci_host *host, struct
mmc_data *data)
host->size = data->blksz * data->blocks;
host->dataend = false;
data->bytes_xfered = 0;
+ host->cache_len = 0;
+ host->cache = 0;
clks = (unsigned long long)data->timeout_ns * host->cclk;
do_div(clks, 1000000000UL);
@@ -712,43 +714,88 @@ static int mmci_pio_write(struct mmci_host *host, char
*buffer, unsigned int rem
struct variant_data *variant = host->variant;
void __iomem *base = host->base;
char *ptr = buffer;
+ unsigned int data_left = host->size;
+ unsigned int count, maxcnt;
+ char *cache_ptr;
+ int i;
do {
- unsigned int count, maxcnt;
-
maxcnt = status & MCI_TXFIFOEMPTY ?
variant->fifosize : variant->fifohalfsize;
- count = min(remain, maxcnt);
/*
- * The ST Micro variant for SDIO transfer sizes
- * less then 8 bytes should have clock H/W flow
- * control disabled.
+ * A write to the FIFO must always be done of 4 bytes aligned
+ * data. If the buffer is not 4 bytes aligned we must pad the
+ * data, but this must only be done for the final write for the
+ * entire data transfer, otherwise we will corrupt the data.
+ * Thus a buffer cache of four bytes is needed to temporary
+ * store data.
*/
- if (variant->sdio &&
- mmc_card_sdio(host->mmc->card)) {
- if (count < 8)
- writel(readl(host->base + MMCICLOCK) &
- ~variant->clkreg_enable,
- host->base + MMCICLOCK);
- else
- writel(readl(host->base + MMCICLOCK) |
- variant->clkreg_enable,
- host->base + MMCICLOCK);
+ if (host->cache_len) {
+ cache_ptr = (char *)&host->cache;
+ cache_ptr = cache_ptr + host->cache_len;
+ data_left += host->cache_len;
+
+ while ((host->cache_len < 4) && (remain > 0)) {
+ *cache_ptr = *ptr;
+ cache_ptr++;
+ ptr++;
+ host->cache_len++;
+ remain--;
+ }
+
+ if ((host->cache_len == 4) ||
+ (data_left == host->cache_len)) {
+
+ writesl(base + MMCIFIFO, &host->cache, 1);
+ if (data_left == host->cache_len)
+ break;
+
+ host->cache = 0;
+ host->cache_len = 0;
+ maxcnt -= 4;
+ data_left -= 4;
+ }
+
+ if (remain == 0)
+ break;
}
- /*
- * SDIO especially may want to send something that is
- * not divisible by 4 (as opposed to card sectors
- * etc), and the FIFO only accept full 32-bit writes.
- * So compensate by adding +3 on the count, a single
- * byte become a 32bit write, 7 bytes will be two
- * 32bit writes etc.
- */
- writesl(base + MMCIFIFO, ptr, (count + 3) >> 2);
+ count = min(remain, maxcnt);
- ptr += count;
- remain -= count;
+ if (!(count % 4) || (data_left == count)) {
+ /*
+ * The data is either 4-bytes aligned or it is the
+ * last data to write. It is thus fine to potentially
+ * pad the data if needed.
+ */
+ writesl(base + MMCIFIFO, ptr, (count + 3) >> 2);
+ ptr += count;
+ remain -= count;
+ data_left -= count;
+
+ } else {
+
+ host->cache_len = count % 4;
+ count = (count >> 2) << 2;
+
+ if (count)
+ writesl(base + MMCIFIFO, ptr, count >> 2);
+
+ ptr += count;
+ remain -= count;
+ data_left -= count;
+
+ i = 0;
+ cache_ptr = (char *)&host->cache;
+ while (i < host->cache_len) {
+ *cache_ptr = *ptr;
+ cache_ptr++;
+ ptr++;
+ remain--;
+ i++;
+ }
+ }
if (remain == 0)
break;
@@ -803,7 +850,10 @@ static irqreturn_t mmci_pio_irq(int irq, void *dev_id)
if (status & MCI_TXACTIVE)
len = mmci_pio_write(host, buffer, remain, status);
- sg_miter->consumed = len;
+ if (len > sg_miter->consumed)
+ len = sg_miter->consumed;
+ else
+ sg_miter->consumed = len;
host->size -= len;
remain -= len;
diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
index 79156a0..ff93a9c 100644
--- a/drivers/mmc/host/mmci.h
+++ b/drivers/mmc/host/mmci.h
@@ -196,6 +196,9 @@ struct mmci_host {
/* pio stuff */
struct sg_mapping_iter sg_miter;
unsigned int size;
+ u32 cache;
+ unsigned int cache_len;
+
struct regulator *vcc;
/* sync of DATAEND irq */
--
1.7.3.2
--
To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
