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-rw-r--r--drivers/mmc/host/sdhci.c164
-rw-r--r--drivers/mmc/host/sdhci.h3
2 files changed, 159 insertions, 8 deletions
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 070aff9c108f..2020e57ffa7e 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -21,6 +21,7 @@
#include <linux/dma-mapping.h>
#include <linux/slab.h>
#include <linux/scatterlist.h>
+#include <linux/sizes.h>
#include <linux/swiotlb.h>
#include <linux/regulator/consumer.h>
#include <linux/pm_runtime.h>
@@ -502,8 +503,35 @@ static int sdhci_pre_dma_transfer(struct sdhci_host *host,
if (data->host_cookie == COOKIE_PRE_MAPPED)
return data->sg_count;
- sg_count = dma_map_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
- mmc_get_dma_dir(data));
+ /* Bounce write requests to the bounce buffer */
+ if (host->bounce_buffer) {
+ unsigned int length = data->blksz * data->blocks;
+
+ if (length > host->bounce_buffer_size) {
+ pr_err("%s: asked for transfer of %u bytes exceeds bounce buffer %u bytes\n",
+ mmc_hostname(host->mmc), length,
+ host->bounce_buffer_size);
+ return -EIO;
+ }
+ if (mmc_get_dma_dir(data) == DMA_TO_DEVICE) {
+ /* Copy the data to the bounce buffer */
+ sg_copy_to_buffer(data->sg, data->sg_len,
+ host->bounce_buffer,
+ length);
+ }
+ /* Switch ownership to the DMA */
+ dma_sync_single_for_device(host->mmc->parent,
+ host->bounce_addr,
+ host->bounce_buffer_size,
+ mmc_get_dma_dir(data));
+ /* Just a dummy value */
+ sg_count = 1;
+ } else {
+ /* Just access the data directly from memory */
+ sg_count = dma_map_sg(mmc_dev(host->mmc),
+ data->sg, data->sg_len,
+ mmc_get_dma_dir(data));
+ }
if (sg_count == 0)
return -ENOSPC;
@@ -673,6 +701,14 @@ static void sdhci_adma_table_post(struct sdhci_host *host,
}
}
+static u32 sdhci_sdma_address(struct sdhci_host *host)
+{
+ if (host->bounce_buffer)
+ return host->bounce_addr;
+ else
+ return sg_dma_address(host->data->sg);
+}
+
static u8 sdhci_calc_timeout(struct sdhci_host *host, struct mmc_command *cmd)
{
u8 count;
@@ -858,8 +894,8 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_command *cmd)
SDHCI_ADMA_ADDRESS_HI);
} else {
WARN_ON(sg_cnt != 1);
- sdhci_writel(host, sg_dma_address(data->sg),
- SDHCI_DMA_ADDRESS);
+ sdhci_writel(host, sdhci_sdma_address(host),
+ SDHCI_DMA_ADDRESS);
}
}
@@ -2255,7 +2291,12 @@ static void sdhci_pre_req(struct mmc_host *mmc, struct mmc_request *mrq)
mrq->data->host_cookie = COOKIE_UNMAPPED;
- if (host->flags & SDHCI_REQ_USE_DMA)
+ /*
+ * No pre-mapping in the pre hook if we're using the bounce buffer,
+ * for that we would need two bounce buffers since one buffer is
+ * in flight when this is getting called.
+ */
+ if (host->flags & SDHCI_REQ_USE_DMA && !host->bounce_buffer)
sdhci_pre_dma_transfer(host, mrq->data, COOKIE_PRE_MAPPED);
}
@@ -2359,8 +2400,45 @@ static bool sdhci_request_done(struct sdhci_host *host)
struct mmc_data *data = mrq->data;
if (data && data->host_cookie == COOKIE_MAPPED) {
- dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
- mmc_get_dma_dir(data));
+ if (host->bounce_buffer) {
+ /*
+ * On reads, copy the bounced data into the
+ * sglist
+ */
+ if (mmc_get_dma_dir(data) == DMA_FROM_DEVICE) {
+ unsigned int length = data->bytes_xfered;
+
+ if (length > host->bounce_buffer_size) {
+ pr_err("%s: bounce buffer is %u bytes but DMA claims to have transferred %u bytes\n",
+ mmc_hostname(host->mmc),
+ host->bounce_buffer_size,
+ data->bytes_xfered);
+ /* Cap it down and continue */
+ length = host->bounce_buffer_size;
+ }
+ dma_sync_single_for_cpu(
+ host->mmc->parent,
+ host->bounce_addr,
+ host->bounce_buffer_size,
+ DMA_FROM_DEVICE);
+ sg_copy_from_buffer(data->sg,
+ data->sg_len,
+ host->bounce_buffer,
+ length);
+ } else {
+ /* No copying, just switch ownership */
+ dma_sync_single_for_cpu(
+ host->mmc->parent,
+ host->bounce_addr,
+ host->bounce_buffer_size,
+ mmc_get_dma_dir(data));
+ }
+ } else {
+ /* Unmap the raw data */
+ dma_unmap_sg(mmc_dev(host->mmc), data->sg,
+ data->sg_len,
+ mmc_get_dma_dir(data));
+ }
data->host_cookie = COOKIE_UNMAPPED;
}
}
@@ -2643,7 +2721,8 @@ static void sdhci_data_irq(struct sdhci_host *host, u32 intmask)
*/
if (intmask & SDHCI_INT_DMA_END) {
u32 dmastart, dmanow;
- dmastart = sg_dma_address(host->data->sg);
+
+ dmastart = sdhci_sdma_address(host);
dmanow = dmastart + host->data->bytes_xfered;
/*
* Force update to the next DMA block boundary.
@@ -3234,6 +3313,68 @@ void __sdhci_read_caps(struct sdhci_host *host, u16 *ver, u32 *caps, u32 *caps1)
}
EXPORT_SYMBOL_GPL(__sdhci_read_caps);
+static int sdhci_allocate_bounce_buffer(struct sdhci_host *host)
+{
+ struct mmc_host *mmc = host->mmc;
+ unsigned int max_blocks;
+ unsigned int bounce_size;
+ int ret;
+
+ /*
+ * Cap the bounce buffer at 64KB. Using a bigger bounce buffer
+ * has diminishing returns, this is probably because SD/MMC
+ * cards are usually optimized to handle this size of requests.
+ */
+ bounce_size = SZ_64K;
+ /*
+ * Adjust downwards to maximum request size if this is less
+ * than our segment size, else hammer down the maximum
+ * request size to the maximum buffer size.
+ */
+ if (mmc->max_req_size < bounce_size)
+ bounce_size = mmc->max_req_size;
+ max_blocks = bounce_size / 512;
+
+ /*
+ * When we just support one segment, we can get significant
+ * speedups by the help of a bounce buffer to group scattered
+ * reads/writes together.
+ */
+ host->bounce_buffer = devm_kmalloc(mmc->parent,
+ bounce_size,
+ GFP_KERNEL);
+ if (!host->bounce_buffer) {
+ pr_err("%s: failed to allocate %u bytes for bounce buffer, falling back to single segments\n",
+ mmc_hostname(mmc),
+ bounce_size);
+ /*
+ * Exiting with zero here makes sure we proceed with
+ * mmc->max_segs == 1.
+ */
+ return 0;
+ }
+
+ host->bounce_addr = dma_map_single(mmc->parent,
+ host->bounce_buffer,
+ bounce_size,
+ DMA_BIDIRECTIONAL);
+ ret = dma_mapping_error(mmc->parent, host->bounce_addr);
+ if (ret)
+ /* Again fall back to max_segs == 1 */
+ return 0;
+ host->bounce_buffer_size = bounce_size;
+
+ /* Lie about this since we're bouncing */
+ mmc->max_segs = max_blocks;
+ mmc->max_seg_size = bounce_size;
+ mmc->max_req_size = bounce_size;
+
+ pr_info("%s bounce up to %u segments into one, max segment size %u bytes\n",
+ mmc_hostname(mmc), max_blocks, bounce_size);
+
+ return 0;
+}
+
int sdhci_setup_host(struct sdhci_host *host)
{
struct mmc_host *mmc;
@@ -3730,6 +3871,13 @@ int sdhci_setup_host(struct sdhci_host *host)
*/
mmc->max_blk_count = (host->quirks & SDHCI_QUIRK_NO_MULTIBLOCK) ? 1 : 65535;
+ if (mmc->max_segs == 1) {
+ /* This may alter mmc->*_blk_* parameters */
+ ret = sdhci_allocate_bounce_buffer(host);
+ if (ret)
+ return ret;
+ }
+
return 0;
unreg:
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index afab26fd70e6..c95b0a4a7594 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -440,6 +440,9 @@ struct sdhci_host {
int irq; /* Device IRQ */
void __iomem *ioaddr; /* Mapped address */
+ char *bounce_buffer; /* For packing SDMA reads/writes */
+ dma_addr_t bounce_addr;
+ unsigned int bounce_buffer_size;
const struct sdhci_ops *ops; /* Low level hw interface */
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-01 10:39:30 +0000