pre_req() runs dma_map_sg() post_req() runs dma_unmap_sg.
If not calling pre_req() before sdhci_request(), request()
will prepare the cache just like it did it before.
It is optional to use pre_req() and post_req().
Signed-off-by: Shawn Guo <shawn....@linaro.org>
---
I worked out the patch by referring to Per's patch below.
omap_hsmmc: add support for pre_req and post_req
It adds pre_req and post_req support for sdhci based host drivers to
work with Per's non-blocking optimization. But I only have imx esdhc
based hardware to test. Unfortunately, I can not measure the
performance gain using mmc_test, because the current esdhc driver on
mainline fails on the test. So I just did a quick test using 'dd',
but sadly, I did not see noticeable performance gain here. The
followings are possible reasons I can think of right away.
* The patch did not add pre_req and post_req correctly. Please help
review to catch the mistakes if any.
* The imx esdhc driver uses SDHCI_SDMA (max_segs is 1) than SDHCI_ADAM
(max_segs is 128), due to the broken ADMA support on imx esdhc. So
can people holding other sdhci based hardware give a try on the
patch?
Hopefully, I can find some time to have a close look at the mmc_test
failure and the broken ADMA with imx esdhc.
Regards,
Shawn
drivers/mmc/host/sdhci.c | 95 ++++++++++++++++++++++++++++++++++++++------
include/linux/mmc/sdhci.h | 7 +++
2 files changed, 89 insertions(+), 13 deletions(-)
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 9e15f41..becce9a 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -408,6 +408,44 @@ static void sdhci_set_adma_desc(u8 *desc, u32 addr, int
len, unsigned cmd)
dataddr[0] = cpu_to_le32(addr);
}
+static int sdhci_pre_dma_transfer(struct sdhci_host *host,
+ struct mmc_data *data,
+ struct sdhci_next *next)
+{
+ int sg_count;
+
+ if (!next && data->host_cookie &&
+ data->host_cookie != host->next_data.cookie) {
+ printk(KERN_WARNING "[%s] invalid cookie: data->host_cookie %d"
+ " host->next_data.cookie %d\n",
+ __func__, data->host_cookie, host->next_data.cookie);
+ data->host_cookie = 0;
+ }
+
+ /* Check if next job is already prepared */
+ if (next ||
+ (!next && data->host_cookie != host->next_data.cookie)) {
+ sg_count = dma_map_sg(mmc_dev(host->mmc), data->sg,
+ data->sg_len,
+ (data->flags & MMC_DATA_WRITE) ?
+ DMA_TO_DEVICE : DMA_FROM_DEVICE);
+ } else {
+ sg_count = host->next_data.sg_count;
+ host->next_data.sg_count = 0;
+ }
+
+ if (sg_count == 0)
+ return -EINVAL;
+
+ if (next) {
+ next->sg_count = sg_count;
+ data->host_cookie = ++next->cookie < 0 ? 1 : next->cookie;
+ } else
+ host->sg_count = sg_count;
+
+ return sg_count;
+}
+
static int sdhci_adma_table_pre(struct sdhci_host *host,
struct mmc_data *data)
{
@@ -445,9 +483,8 @@ static int sdhci_adma_table_pre(struct sdhci_host *host,
goto fail;
BUG_ON(host->align_addr & 0x3);
- host->sg_count = dma_map_sg(mmc_dev(host->mmc),
- data->sg, data->sg_len, direction);
- if (host->sg_count == 0)
+ host->sg_count = sdhci_pre_dma_transfer(host, data, NULL);
+ if (host->sg_count < 0)
goto unmap_align;
desc = host->adma_desc;
@@ -587,8 +624,9 @@ static void sdhci_adma_table_post(struct sdhci_host *host,
}
}
- dma_unmap_sg(mmc_dev(host->mmc), data->sg,
- data->sg_len, direction);
+ if (!data->host_cookie)
+ dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
+ direction);
}
static u8 sdhci_calc_timeout(struct sdhci_host *host, struct mmc_data *data)
@@ -757,11 +795,7 @@ static void sdhci_prepare_data(struct sdhci_host *host,
struct mmc_data *data)
} else {
int sg_cnt;
- sg_cnt = dma_map_sg(mmc_dev(host->mmc),
- data->sg, data->sg_len,
- (data->flags & MMC_DATA_READ) ?
- DMA_FROM_DEVICE :
- DMA_TO_DEVICE);
+ sg_cnt = sdhci_pre_dma_transfer(host, data, NULL);
if (sg_cnt == 0) {
/*
* This only happens when someone fed
@@ -850,9 +884,11 @@ static void sdhci_finish_data(struct sdhci_host *host)
if (host->flags & SDHCI_USE_ADMA)
sdhci_adma_table_post(host, data);
else {
- dma_unmap_sg(mmc_dev(host->mmc), data->sg,
- data->sg_len, (data->flags & MMC_DATA_READ) ?
- DMA_FROM_DEVICE : DMA_TO_DEVICE);
+ if (!data->host_cookie)
+ dma_unmap_sg(mmc_dev(host->mmc), data->sg,
+ data->sg_len,
+ (data->flags & MMC_DATA_READ) ?
+ DMA_FROM_DEVICE : DMA_TO_DEVICE);
}
}
@@ -1116,6 +1152,35 @@ static void sdhci_set_power(struct sdhci_host *host,
unsigned short power)
* *
\*****************************************************************************/
+static void sdhci_pre_req(struct mmc_host *mmc, struct mmc_request *mrq,
+ bool is_first_req)
+{
+ struct sdhci_host *host = mmc_priv(mmc);
+
+ if (mrq->data->host_cookie) {
+ mrq->data->host_cookie = 0;
+ return;
+ }
+
+ if (host->flags & SDHCI_REQ_USE_DMA)
+ if (sdhci_pre_dma_transfer(host, mrq->data, &host->next_data) <
0)
+ mrq->data->host_cookie = 0;
+}
+
+static void sdhci_post_req(struct mmc_host *mmc, struct mmc_request *mrq,
+ int err)
+{
+ struct sdhci_host *host = mmc_priv(mmc);
+ struct mmc_data *data = mrq->data;
+
+ if (host->flags & SDHCI_REQ_USE_DMA) {
+ dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
+ (data->flags & MMC_DATA_WRITE) ?
+ DMA_TO_DEVICE : DMA_FROM_DEVICE);
+ data->host_cookie = 0;
+ }
+}
+
static void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
{
struct sdhci_host *host;
@@ -1285,6 +1350,8 @@ out:
}
static const struct mmc_host_ops sdhci_ops = {
+ .pre_req = sdhci_pre_req,
+ .post_req = sdhci_post_req,
.request = sdhci_request,
.set_ios = sdhci_set_ios,
.get_ro = sdhci_get_ro,
@@ -1867,6 +1934,8 @@ int sdhci_add_host(struct sdhci_host *host)
if (caps & SDHCI_TIMEOUT_CLK_UNIT)
host->timeout_clk *= 1000;
+ host->next_data.cookie = 1;
+
/*
* Set host parameters.
*/
diff --git a/include/linux/mmc/sdhci.h b/include/linux/mmc/sdhci.h
index 83bd9f7..924e84b 100644
--- a/include/linux/mmc/sdhci.h
+++ b/include/linux/mmc/sdhci.h
@@ -17,6 +17,11 @@
#include <linux/io.h>
#include <linux/mmc/host.h>
+struct sdhci_next {
+ unsigned int sg_count;
+ s32 cookie;
+};
+
struct sdhci_host {
/* Data set by hardware interface driver */
const char *hw_name; /* Hardware bus name */
@@ -145,6 +150,8 @@ struct sdhci_host {
unsigned int ocr_avail_sd;
unsigned int ocr_avail_mmc;
+ struct sdhci_next next_data;
+
unsigned long private[0] ____cacheline_aligned;
};
#endif /* __SDHCI_H */
--
1.7.4.1
--
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