diff --git a/common/bouncebuf.c b/common/bouncebuf.c
index 4f827f893d665d66963a7f32aeaea4f00222d9d2..1df12cdda07d04f80632190c09b841e85a774b45 100644
--- a/common/bouncebuf.c
+++ b/common/bouncebuf.c
@@ -27,21 +27,19 @@
#include <errno.h>
#include <bouncebuf.h>
-static int addr_aligned(void *data, size_t len)
+static int addr_aligned(struct bounce_buffer *state)
{
const ulong align_mask = ARCH_DMA_MINALIGN - 1;
/* Check if start is aligned */
- if ((ulong)data & align_mask) {
- debug("Unaligned start address %p\n", data);
+ if ((ulong)state->user_buffer & align_mask) {
+ debug("Unaligned buffer address %p\n", state->user_buffer);
return 0;
}
- data += len;
-
- /* Check if end is aligned */
- if ((ulong)data & align_mask) {
- debug("Unaligned end address %p\n", data);
+ /* Check if length is aligned */
+ if (state->len != state->len_aligned) {
+ debug("Unaligned buffer length %d\n", state->len);
return 0;
}
@@ -49,44 +47,53 @@ static int addr_aligned(void *data, size_t len)
return 1;
}
-int bounce_buffer_start(void **data, size_t len, void **backup, uint8_t flags)
+int bounce_buffer_start(struct bounce_buffer *state, void *data,
+ size_t len, unsigned int flags)
{
- void *tmp;
- size_t alen;
-
- if (addr_aligned(*data, len)) {
- *backup = NULL;
- return 0;
+ state->user_buffer = data;
+ state->bounce_buffer = data;
+ state->len = len;
+ state->len_aligned = roundup(len, ARCH_DMA_MINALIGN);
+ state->flags = flags;
+
+ if (!addr_aligned(state)) {
+ state->bounce_buffer = memalign(ARCH_DMA_MINALIGN,
+ state->len_aligned);
+ if (!state->bounce_buffer)
+ return -ENOMEM;
+
+ if (state->flags & GEN_BB_READ)
+ memcpy(state->bounce_buffer, state->user_buffer,
+ state->len);
}
- alen = roundup(len, ARCH_DMA_MINALIGN);
- tmp = memalign(ARCH_DMA_MINALIGN, alen);
-
- if (!tmp)
- return -ENOMEM;
-
- if (flags & GEN_BB_READ)
- memcpy(tmp, *data, len);
-
- *backup = *data;
- *data = tmp;
+ /*
+ * Flush data to RAM so DMA reads can pick it up,
+ * and any CPU writebacks don't race with DMA writes
+ */
+ flush_dcache_range((unsigned long)state->bounce_buffer,
+ (unsigned long)(state->bounce_buffer) +
+ state->len_aligned);
return 0;
}
-int bounce_buffer_stop(void **data, size_t len, void **backup, uint8_t flags)
+int bounce_buffer_stop(struct bounce_buffer *state)
{
- void *tmp = *data;
+ if (state->flags & GEN_BB_WRITE) {
+ /* Invalidate cache so that CPU can see any newly DMA'd data */
+ invalidate_dcache_range((unsigned long)state->bounce_buffer,
+ (unsigned long)(state->bounce_buffer) +
+ state->len_aligned);
+ }
- /* The buffer was already aligned, since "backup" is NULL. */
- if (!*backup)
+ if (state->bounce_buffer == state->user_buffer)
return 0;
- if (flags & GEN_BB_WRITE)
- memcpy(*backup, *data, len);
+ if (state->flags & GEN_BB_WRITE)
+ memcpy(state->user_buffer, state->bounce_buffer, state->len);
- *data = *backup;
- free(tmp);
+ free(state->bounce_buffer);
return 0;
}
diff --git a/drivers/mmc/mxsmmc.c b/drivers/mmc/mxsmmc.c
index 109acbf6234bf3eb29e4caf9ba18f5c4294e784e..024df592f2256bd7f846683fd1f8d3ff61baa529 100644
--- a/drivers/mmc/mxsmmc.c
+++ b/drivers/mmc/mxsmmc.c
@@ -96,11 +96,11 @@ static int mxsmmc_send_cmd_pio(struct mxsmmc_priv *priv, struct mmc_data *data)
static int mxsmmc_send_cmd_dma(struct mxsmmc_priv *priv, struct mmc_data *data)
{
uint32_t data_count = data->blocksize * data->blocks;
- uint32_t cache_data_count = roundup(data_count, ARCH_DMA_MINALIGN);
int dmach;
struct mxs_dma_desc *desc = priv->desc;
- void *addr, *backup;
- uint8_t flags;
+ void *addr;
+ unsigned int flags;
+ struct bounce_buffer bbstate;
memset(desc, 0, sizeof(struct mxs_dma_desc));
desc->address = (dma_addr_t)desc;
@@ -115,19 +115,9 @@ static int mxsmmc_send_cmd_dma(struct mxsmmc_priv *priv, struct mmc_data *data)
flags = GEN_BB_READ;
}
- bounce_buffer_start(&addr, data_count, &backup, flags);
+ bounce_buffer_start(&bbstate, addr, data_count, flags);
- priv->desc->cmd.address = (dma_addr_t)addr;
-
- if (data->flags & MMC_DATA_WRITE) {
- /* Flush data to DRAM so DMA can pick them up */
- flush_dcache_range((uint32_t)addr,
- (uint32_t)(addr) + cache_data_count);
- }
-
- /* Invalidate the area, so no writeback into the RAM races with DMA */
- invalidate_dcache_range((uint32_t)priv->desc->cmd.address,
- (uint32_t)(priv->desc->cmd.address + cache_data_count));
+ priv->desc->cmd.address = (dma_addr_t)bbstate.bounce_buffer;
priv->desc->cmd.data |= MXS_DMA_DESC_IRQ | MXS_DMA_DESC_DEC_SEM |
(data_count << MXS_DMA_DESC_BYTES_OFFSET);
@@ -135,17 +125,11 @@ static int mxsmmc_send_cmd_dma(struct mxsmmc_priv *priv, struct mmc_data *data)
dmach = MXS_DMA_CHANNEL_AHB_APBH_SSP0 + priv->id;
mxs_dma_desc_append(dmach, priv->desc);
if (mxs_dma_go(dmach)) {
- bounce_buffer_stop(&addr, data_count, &backup, flags);
+ bounce_buffer_stop(&bbstate);
return COMM_ERR;
}
- /* The data arrived into DRAM, invalidate cache over them */
- if (data->flags & MMC_DATA_READ) {
- invalidate_dcache_range((uint32_t)addr,
- (uint32_t)(addr) + cache_data_count);
- }
-
- bounce_buffer_stop(&addr, data_count, &backup, flags);
+ bounce_buffer_stop(&bbstate);
return 0;
}
diff --git a/include/bouncebuf.h b/include/bouncebuf.h
index aa2278c8f94ad05355b1d29bbee1104459e9e064..707b588c733c06d936a0a2fa517b9c4fad47095a 100644
--- a/include/bouncebuf.h
+++ b/include/bouncebuf.h
@@ -25,6 +25,8 @@
#ifndef __INCLUDE_BOUNCEBUF_H__
#define __INCLUDE_BOUNCEBUF_H__
+#include <linux/types.h>
+
/*
* GEN_BB_READ -- Data are read from the buffer eg. by DMA hardware.
* The source buffer is copied into the bounce buffer (if unaligned, otherwise
@@ -51,23 +53,36 @@
*/
#define GEN_BB_RW (GEN_BB_READ | GEN_BB_WRITE)
+struct bounce_buffer {
+ /* Copy of data parameter passed to start() */
+ void *user_buffer;
+ /*
+ * DMA-aligned buffer. This field is always set to the value that
+ * should be used for DMA; either equal to .user_buffer, or to a
+ * freshly allocated aligned buffer.
+ */
+ void *bounce_buffer;
+ /* Copy of len parameter passed to start() */
+ size_t len;
+ /* DMA-aligned buffer length */
+ size_t len_aligned;
+ /* Copy of flags parameter passed to start() */
+ unsigned int flags;
+};
+
/**
* bounce_buffer_start() -- Start the bounce buffer session
+ * state: stores state passed between bounce_buffer_{start,stop}
* data: pointer to buffer to be aligned
* len: length of the buffer
- * backup: pointer to backup buffer (the original value is stored here if
- * needed
* flags: flags describing the transaction, see above.
*/
-int bounce_buffer_start(void **data, size_t len, void **backup, uint8_t flags);
+int bounce_buffer_start(struct bounce_buffer *state, void *data,
+ size_t len, unsigned int flags);
/**
* bounce_buffer_stop() -- Finish the bounce buffer session
- * data: pointer to buffer that was aligned
- * len: length of the buffer
- * backup: pointer to backup buffer (the original value is stored here if
- * needed
- * flags: flags describing the transaction, see above.
+ * state: stores state passed between bounce_buffer_{start,stop}
*/
-int bounce_buffer_stop(void **data, size_t len, void **backup, uint8_t flags);
+int bounce_buffer_stop(struct bounce_buffer *state);
#endif