[U-Boot] [PATCH 3/3] mmc: tegra: use bounce buffer APIs
Stephen Warren
swarren at wwwdotorg.org
Tue Nov 6 00:04:02 CET 2012
From: Stephen Warren <swarren at nvidia.com>
Tegra's MMC driver does DMA, and hence needs cache-aligned buffers. In
some cases (e.g. user load commands) this cannot be guaranteed by callers
of the MMC APIs. To solve this, modify the Tegra MMC driver to use the
new bounce_buffer_*() APIs.
Note: Ideally, all U-Boot code will always provide address- and size-
aligned buffers, so a bounce buffer will only ever be needed for user-
supplied buffers (e.g. load commands). Ensuring this removes the need
for performance-sucking bounce buffer memory allocations and memcpy()s.
The one known exception at present is the SCR buffer in sd_change_freq(),
which is only 8 bytes long. Solving this requires enhancing struct
mmc_data to know the difference between buffer size and transferred data
size, or forcing all callers of mmc_send_cmd() to have allocated buffers
using ALLOC_CACHE_ALIGN_BUFFER(), which will true in this case, is not
enforced in any way at present, and so cannot be assumed by the core MMC
code.
Signed-off-by: Stephen Warren <swarren at nvidia.com>
---
drivers/mmc/tegra_mmc.c | 81 +++++++++++++++++++++++------------
include/configs/tegra-common-post.h | 4 ++
2 files changed, 58 insertions(+), 27 deletions(-)
diff --git a/drivers/mmc/tegra_mmc.c b/drivers/mmc/tegra_mmc.c
index 1fd5592..e5d55b0 100644
--- a/drivers/mmc/tegra_mmc.c
+++ b/drivers/mmc/tegra_mmc.c
@@ -26,6 +26,7 @@
#include <asm/arch-tegra/clk_rst.h>
#include <asm/arch-tegra/tegra_mmc.h>
#include <mmc.h>
+#include <bouncebuf.h>
/* support 4 mmc hosts */
struct mmc mmc_dev[4];
@@ -66,14 +67,34 @@ static void tegra_get_setup(struct mmc_host *host, int dev_index)
host->reg = (struct tegra_mmc *)host->base;
}
-static void mmc_prepare_data(struct mmc_host *host, struct mmc_data *data)
+static void mmc_prepare_data(struct mmc_host *host, struct mmc_data *data,
+ struct bounce_buffer_state *bbstate)
{
unsigned char ctrl;
+ void *buf;
+ uint8_t bbflags;
+ size_t len;
+
+ if (data->flags & MMC_DATA_READ) {
+ buf = data->dest;
+ bbflags = GEN_BB_WRITE;
+ } else {
+ buf = (void *)data->src;
+ bbflags = GEN_BB_READ;
+ }
+ len = data->blocks * data->blocksize;
+
+ bounce_buffer_start(bbstate, buf, len, bbflags);
+
+ debug("buf: %08X, data->blocks: %u, data->blocksize: %u\n",
+ (u32)bbstate->bounce_buffer, data->blocks, data->blocksize);
- debug("data->dest: %08X, data->blocks: %u, data->blocksize: %u\n",
- (u32)data->dest, data->blocks, data->blocksize);
+ if (data->flags & MMC_DATA_WRITE)
+ flush_dcache_range((ulong)bbstate->bounce_buffer,
+ (ulong)bbstate->bounce_buffer +
+ bbstate->len_aligned);
- writel((u32)data->dest, &host->reg->sysad);
+ writel((u32)bbstate->bounce_buffer, &host->reg->sysad);
/*
* DMASEL[4:3]
* 00 = Selects SDMA
@@ -114,14 +135,6 @@ static void mmc_set_transfer_mode(struct mmc_host *host, struct mmc_data *data)
if (data->flags & MMC_DATA_READ)
mode |= TEGRA_MMC_TRNMOD_DATA_XFER_DIR_SEL_READ;
- if (data->flags & MMC_DATA_WRITE) {
- if ((uintptr_t)data->src & (ARCH_DMA_MINALIGN - 1))
- printf("Warning: unaligned write to %p may fail\n",
- data->src);
- flush_dcache_range((ulong)data->src, (ulong)data->src +
- data->blocks * data->blocksize);
- }
-
writew(mode, &host->reg->trnmod);
}
@@ -164,6 +177,9 @@ static int mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
int result;
unsigned int mask = 0;
unsigned int retry = 0x100000;
+ struct bounce_buffer_state bbstate;
+ int ret;
+
debug(" mmc_send_cmd called\n");
result = mmc_wait_inhibit(host, cmd, data, 10 /* ms */);
@@ -172,7 +188,7 @@ static int mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
return result;
if (data)
- mmc_prepare_data(host, data);
+ mmc_prepare_data(host, data, &bbstate);
debug("cmd->arg: %08x\n", cmd->cmdarg);
writel(cmd->cmdarg, &host->reg->argument);
@@ -180,8 +196,10 @@ static int mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
if (data)
mmc_set_transfer_mode(host, data);
- if ((cmd->resp_type & MMC_RSP_136) && (cmd->resp_type & MMC_RSP_BUSY))
- return -1;
+ if ((cmd->resp_type & MMC_RSP_136) && (cmd->resp_type & MMC_RSP_BUSY)) {
+ ret = -1;
+ goto cleanup;
+ }
/*
* CMDREG
@@ -228,19 +246,22 @@ static int mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
if (i == retry) {
printf("%s: waiting for status update\n", __func__);
writel(mask, &host->reg->norintsts);
- return TIMEOUT;
+ ret = TIMEOUT;
+ goto cleanup;
}
if (mask & TEGRA_MMC_NORINTSTS_CMD_TIMEOUT) {
/* Timeout Error */
debug("timeout: %08x cmd %d\n", mask, cmd->cmdidx);
writel(mask, &host->reg->norintsts);
- return TIMEOUT;
+ ret = TIMEOUT;
+ goto cleanup;
} else if (mask & TEGRA_MMC_NORINTSTS_ERR_INTERRUPT) {
/* Error Interrupt */
debug("error: %08x cmd %d\n", mask, cmd->cmdidx);
writel(mask, &host->reg->norintsts);
- return -1;
+ ret = -1;
+ goto cleanup;
}
if (cmd->resp_type & MMC_RSP_PRESENT) {
@@ -269,7 +290,8 @@ static int mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
if (i == retry) {
printf("%s: card is still busy\n", __func__);
writel(mask, &host->reg->norintsts);
- return TIMEOUT;
+ ret = TIMEOUT;
+ goto cleanup;
}
cmd->response[0] = readl(&host->reg->rspreg0);
@@ -291,7 +313,8 @@ static int mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
writel(mask, &host->reg->norintsts);
printf("%s: error during transfer: 0x%08x\n",
__func__, mask);
- return -1;
+ ret = -1;
+ goto cleanup;
} else if (mask & TEGRA_MMC_NORINTSTS_DMA_INTERRUPT) {
/*
* DMA Interrupt, restart the transfer where
@@ -318,22 +341,26 @@ static int mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
readl(&host->reg->norintstsen),
readl(&host->reg->norintsigen),
readl(&host->reg->prnsts));
- return -1;
+ ret = -1;
+ goto cleanup;
}
}
writel(mask, &host->reg->norintsts);
if (data->flags & MMC_DATA_READ) {
- if ((uintptr_t)data->dest & (ARCH_DMA_MINALIGN - 1))
- printf("Warning: unaligned read from %p "
- "may fail\n", data->dest);
- invalidate_dcache_range((ulong)data->dest,
- (ulong)data->dest +
- data->blocks * data->blocksize);
+ invalidate_dcache_range((ulong)bbstate.bounce_buffer,
+ (ulong)bbstate.bounce_buffer +
+ bbstate.len_aligned);
}
+ bounce_buffer_stop(&bbstate);
}
udelay(1000);
return 0;
+
+cleanup:
+ if (data)
+ bounce_buffer_stop(&bbstate);
+ return ret;
}
static void mmc_change_clock(struct mmc_host *host, uint clock)
diff --git a/include/configs/tegra-common-post.h b/include/configs/tegra-common-post.h
index ab62e71..2d45933 100644
--- a/include/configs/tegra-common-post.h
+++ b/include/configs/tegra-common-post.h
@@ -251,4 +251,8 @@
#endif /* CONFIG_SPL_BUILD */
+#ifdef CONFIG_TEGRA_MMC
+#define CONFIG_BOUNCE_BUFFER
+#endif
+
#endif /* __TEGRA_COMMON_POST_H */
--
1.7.0.4
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