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sdhci: highmem capable PIO routines
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Improve the PIO handling so that it can service highmem pages.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
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Pierre Ossman committed Jul 23, 2008
1 parent 137d3ed commit 7659150
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Showing 2 changed files with 75 additions and 95 deletions.
163 changes: 72 additions & 91 deletions drivers/mmc/host/sdhci.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -173,119 +173,95 @@ static void sdhci_led_control(struct led_classdev *led,
* *
\*****************************************************************************/

static inline char* sdhci_sg_to_buffer(struct sdhci_host* host)
{
return sg_virt(host->cur_sg);
}

static inline int sdhci_next_sg(struct sdhci_host* host)
{
/*
* Skip to next SG entry.
*/
host->cur_sg++;
host->num_sg--;

/*
* Any entries left?
*/
if (host->num_sg > 0) {
host->offset = 0;
host->remain = host->cur_sg->length;
}

return host->num_sg;
}

static void sdhci_read_block_pio(struct sdhci_host *host)
{
int blksize, chunk_remain;
u32 data;
char *buffer;
int size;
unsigned long flags;
size_t blksize, len, chunk;
u32 scratch;
u8 *buf;

DBG("PIO reading\n");

blksize = host->data->blksz;
chunk_remain = 0;
data = 0;
chunk = 0;

buffer = sdhci_sg_to_buffer(host) + host->offset;
local_irq_save(flags);

while (blksize) {
if (chunk_remain == 0) {
data = readl(host->ioaddr + SDHCI_BUFFER);
chunk_remain = min(blksize, 4);
}
if (!sg_miter_next(&host->sg_miter))
BUG();

size = min(host->remain, chunk_remain);
len = min(host->sg_miter.length, blksize);

chunk_remain -= size;
blksize -= size;
host->offset += size;
host->remain -= size;
blksize -= len;
host->sg_miter.consumed = len;

while (size) {
*buffer = data & 0xFF;
buffer++;
data >>= 8;
size--;
}
buf = host->sg_miter.addr;

if (host->remain == 0) {
if (sdhci_next_sg(host) == 0) {
BUG_ON(blksize != 0);
return;
while (len) {
if (chunk == 0) {
scratch = readl(host->ioaddr + SDHCI_BUFFER);
chunk = 4;
}
buffer = sdhci_sg_to_buffer(host);

*buf = scratch & 0xFF;

buf++;
scratch >>= 8;
chunk--;
len--;
}
}

sg_miter_stop(&host->sg_miter);

local_irq_restore(flags);
}

static void sdhci_write_block_pio(struct sdhci_host *host)
{
int blksize, chunk_remain;
u32 data;
char *buffer;
int bytes, size;
unsigned long flags;
size_t blksize, len, chunk;
u32 scratch;
u8 *buf;

DBG("PIO writing\n");

blksize = host->data->blksz;
chunk_remain = 4;
data = 0;
chunk = 0;
scratch = 0;

bytes = 0;
buffer = sdhci_sg_to_buffer(host) + host->offset;
local_irq_save(flags);

while (blksize) {
size = min(host->remain, chunk_remain);

chunk_remain -= size;
blksize -= size;
host->offset += size;
host->remain -= size;

while (size) {
data >>= 8;
data |= (u32)*buffer << 24;
buffer++;
size--;
}
if (!sg_miter_next(&host->sg_miter))
BUG();

if (chunk_remain == 0) {
writel(data, host->ioaddr + SDHCI_BUFFER);
chunk_remain = min(blksize, 4);
}
len = min(host->sg_miter.length, blksize);

blksize -= len;
host->sg_miter.consumed = len;

buf = host->sg_miter.addr;

if (host->remain == 0) {
if (sdhci_next_sg(host) == 0) {
BUG_ON(blksize != 0);
return;
while (len) {
scratch |= (u32)*buf << (chunk * 8);

buf++;
chunk++;
len--;

if ((chunk == 4) || ((len == 0) && (blksize == 0))) {
writel(scratch, host->ioaddr + SDHCI_BUFFER);
chunk = 0;
scratch = 0;
}
buffer = sdhci_sg_to_buffer(host);
}
}

sg_miter_stop(&host->sg_miter);

local_irq_restore(flags);
}

static void sdhci_transfer_pio(struct sdhci_host *host)
Expand All @@ -294,7 +270,7 @@ static void sdhci_transfer_pio(struct sdhci_host *host)

BUG_ON(!host->data);

if (host->num_sg == 0)
if (host->blocks == 0)
return;

if (host->data->flags & MMC_DATA_READ)
Expand All @@ -308,7 +284,8 @@ static void sdhci_transfer_pio(struct sdhci_host *host)
else
sdhci_write_block_pio(host);

if (host->num_sg == 0)
host->blocks--;
if (host->blocks == 0)
break;
}

Expand Down Expand Up @@ -713,11 +690,9 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_data *data)
}

if (!(host->flags & SDHCI_REQ_USE_DMA)) {
host->cur_sg = data->sg;
host->num_sg = data->sg_len;

host->offset = 0;
host->remain = host->cur_sg->length;
sg_miter_start(&host->sg_miter,
data->sg, data->sg_len, SG_MITER_ATOMIC);
host->blocks = data->blocks;
}

/* We do not handle DMA boundaries, so set it to max (512 KiB) */
Expand Down Expand Up @@ -1583,9 +1558,15 @@ int sdhci_add_host(struct sdhci_host *host)
}
}

/* XXX: Hack to get MMC layer to avoid highmem */
if (!(host->flags & SDHCI_USE_DMA))
mmc_dev(host->mmc)->dma_mask = NULL;
/*
* If we use DMA, then it's up to the caller to set the DMA
* mask, but PIO does not need the hw shim so we set a new
* mask here in that case.
*/
if (!(host->flags & SDHCI_USE_DMA)) {
host->dma_mask = DMA_BIT_MASK(64);
mmc_dev(host->mmc)->dma_mask = &host->dma_mask;
}

host->max_clk =
(caps & SDHCI_CLOCK_BASE_MASK) >> SDHCI_CLOCK_BASE_SHIFT;
Expand Down
7 changes: 3 additions & 4 deletions drivers/mmc/host/sdhci.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -212,6 +212,7 @@ struct sdhci_host {

/* Internal data */
struct mmc_host *mmc; /* MMC structure */
u64 dma_mask; /* custom DMA mask */

#ifdef CONFIG_LEDS_CLASS
struct led_classdev led; /* LED control */
Expand All @@ -238,10 +239,8 @@ struct sdhci_host {
struct mmc_data *data; /* Current data request */
unsigned int data_early:1; /* Data finished before cmd */

struct scatterlist *cur_sg; /* We're working on this */
int num_sg; /* Entries left */
int offset; /* Offset into current sg */
int remain; /* Bytes left in current */
struct sg_mapping_iter sg_miter; /* SG state for PIO */
unsigned int blocks; /* remaining PIO blocks */

int sg_count; /* Mapped sg entries */

Expand Down

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