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ARM: 6237/1: mmci: use sg_miter API to fix multi-page sg handling

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The mmci driver's SG list iteration logic assumes that each SG entry
spans only one page, and only maps and flushes one page of the sg.  This
is not a valid assumption.  Fix it by converting the driver to the
sg_miter API, which correctly handles sgs which span multiple pages.

Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Rabin Vincent 2010-07-21 12:44:58 +01:00 committed by Russell King
parent 2c39c9e149
commit 4ce1d6cbf0
2 changed files with 39 additions and 56 deletions
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60
drivers/mmc/host/mmci.c
View File

@ -26,7 +26,6 @@
#include <linux/amba/mmci.h>
#include <linux/regulator/consumer.h>
#include <asm/cacheflush.h>
#include <asm/div64.h>
#include <asm/io.h>
#include <asm/sizes.h>
@ -98,6 +97,18 @@ static void mmci_stop_data(struct mmci_host *host)
host->data = NULL;
}
static void mmci_init_sg(struct mmci_host *host, struct mmc_data *data)
{
unsigned int flags = SG_MITER_ATOMIC;
if (data->flags & MMC_DATA_READ)
flags |= SG_MITER_TO_SG;
else
flags |= SG_MITER_FROM_SG;
sg_miter_start(&host->sg_miter, data->sg, data->sg_len, flags);
}
static void mmci_start_data(struct mmci_host *host, struct mmc_data *data)
{
unsigned int datactrl, timeout, irqmask;
@ -210,8 +221,17 @@ mmci_data_irq(struct mmci_host *host, struct mmc_data *data,
* We hit an error condition. Ensure that any data
* partially written to a page is properly coherent.
*/
if (host->sg_len && data->flags & MMC_DATA_READ)
flush_dcache_page(sg_page(host->sg_ptr));
if (data->flags & MMC_DATA_READ) {
struct sg_mapping_iter *sg_miter = &host->sg_miter;
unsigned long flags;
local_irq_save(flags);
if (sg_miter_next(sg_miter)) {
flush_dcache_page(sg_miter->page);
sg_miter_stop(sg_miter);
}
local_irq_restore(flags);
}
}
if (status & MCI_DATAEND) {
mmci_stop_data(host);
@ -314,15 +334,18 @@ static int mmci_pio_write(struct mmci_host *host, char *buffer, unsigned int rem
static irqreturn_t mmci_pio_irq(int irq, void *dev_id)
{
struct mmci_host *host = dev_id;
struct sg_mapping_iter *sg_miter = &host->sg_miter;
void __iomem *base = host->base;
unsigned long flags;
u32 status;
status = readl(base + MMCISTATUS);
dev_dbg(mmc_dev(host->mmc), "irq1 (pio) %08x\n", status);
local_irq_save(flags);
do {
unsigned long flags;
unsigned int remain, len;
char *buffer;
@ -336,11 +359,11 @@ static irqreturn_t mmci_pio_irq(int irq, void *dev_id)
if (!(status & (MCI_TXFIFOHALFEMPTY|MCI_RXDATAAVLBL)))
break;
/*
* Map the current scatter buffer.
*/
buffer = mmci_kmap_atomic(host, &flags) + host->sg_off;
remain = host->sg_ptr->length - host->sg_off;
if (!sg_miter_next(sg_miter))
break;
buffer = sg_miter->addr;
remain = sg_miter->length;
len = 0;
if (status & MCI_RXACTIVE)
@ -348,31 +371,24 @@ static irqreturn_t mmci_pio_irq(int irq, void *dev_id)
if (status & MCI_TXACTIVE)
len = mmci_pio_write(host, buffer, remain, status);
/*
* Unmap the buffer.
*/
mmci_kunmap_atomic(host, buffer, &flags);
sg_miter->consumed = len;
host->sg_off += len;
host->size -= len;
remain -= len;
if (remain)
break;
/*
* If we were reading, and we have completed this
* page, ensure that the data cache is coherent.
*/
if (status & MCI_RXACTIVE)
flush_dcache_page(sg_page(host->sg_ptr));
if (!mmci_next_sg(host))
break;
flush_dcache_page(sg_miter->page);
status = readl(base + MMCISTATUS);
} while (1);
sg_miter_stop(sg_miter);
local_irq_restore(flags);
/*
* If we're nearing the end of the read, switch to
* "any data available" mode.

35
drivers/mmc/host/mmci.h
View File

@ -171,42 +171,9 @@ struct mmci_host {
struct timer_list timer;
unsigned int oldstat;
unsigned int sg_len;
/* pio stuff */
struct scatterlist *sg_ptr;
unsigned int sg_off;
struct sg_mapping_iter sg_miter;
unsigned int size;
struct regulator *vcc;
};
static inline void mmci_init_sg(struct mmci_host *host, struct mmc_data *data)
{
/*
* Ideally, we want the higher levels to pass us a scatter list.
*/
host->sg_len = data->sg_len;
host->sg_ptr = data->sg;
host->sg_off = 0;
}
static inline int mmci_next_sg(struct mmci_host *host)
{
host->sg_ptr++;
host->sg_off = 0;
return --host->sg_len;
}
static inline char *mmci_kmap_atomic(struct mmci_host *host, unsigned long *flags)
{
struct scatterlist *sg = host->sg_ptr;
local_irq_save(*flags);
return kmap_atomic(sg_page(sg), KM_BIO_SRC_IRQ) + sg->offset;
}
static inline void mmci_kunmap_atomic(struct mmci_host *host, void *buffer, unsigned long *flags)
{
kunmap_atomic(buffer, KM_BIO_SRC_IRQ);
local_irq_restore(*flags);
}