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authorPavel Pisa <ppisa@pikron.com>2006-09-07 16:53:29 +0200
committerRussell King <rmk+kernel@arm.linux.org.uk>2006-09-07 16:53:29 +0200
commit148f93d59cc9bb5e0f9a04d36a6f91d435e1a3f7 (patch)
tree1a413a79d37661199786f6fe2db3fe8bd7b5556a /drivers
parent[MMC] Fix SD timeout calculation (diff)
downloadlinux-148f93d59cc9bb5e0f9a04d36a6f91d435e1a3f7.tar.xz
linux-148f93d59cc9bb5e0f9a04d36a6f91d435e1a3f7.zip
[ARM] 3751/1: i.MX/MX1 SD/MMC use 512 bytes request for SCR read
Patch from Pavel Pisa This is another approach to SDHC deficiency workaround. It seems, that previous solution based on 16 bytes (FIFO length size) read is still timing sensitive on genirq and fully preemptive kernels. The new solution is backuped by M9328 UM statement, that only 512 byte block are working properly and by 2.4.26 FreeScale's SDHC code. Jay Monkman reports significant improvement on code based on this driver after applying this change on MX21 as well. Signed-off-by: Pavel Pisa <pisa@cmp.felk.cvut.cz> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/mmc/imxmmc.c69
1 files changed, 35 insertions, 34 deletions
diff --git a/drivers/mmc/imxmmc.c b/drivers/mmc/imxmmc.c
index 7ca9e95bdf89..fb6565b98f32 100644
--- a/drivers/mmc/imxmmc.c
+++ b/drivers/mmc/imxmmc.c
@@ -91,6 +91,8 @@ struct imxmci_host {
int dma_allocated;
unsigned char actual_bus_width;
+
+ int prev_cmd_code;
};
#define IMXMCI_PEND_IRQ_b 0
@@ -248,16 +250,14 @@ static void imxmci_setup_data(struct imxmci_host *host, struct mmc_data *data)
* partial FIFO fills and reads. The length has to be rounded up to burst size multiple.
* This is required for SCR read at least.
*/
- if (datasz < 64) {
+ if (datasz < 512) {
host->dma_size = datasz;
if (data->flags & MMC_DATA_READ) {
host->dma_dir = DMA_FROM_DEVICE;
/* Hack to enable read SCR */
- if(datasz < 16) {
- MMC_NOB = 1;
- MMC_BLK_LEN = 16;
- }
+ MMC_NOB = 1;
+ MMC_BLK_LEN = 512;
} else {
host->dma_dir = DMA_TO_DEVICE;
}
@@ -409,6 +409,9 @@ static void imxmci_finish_request(struct imxmci_host *host, struct mmc_request *
spin_unlock_irqrestore(&host->lock, flags);
+ if(req && req->cmd)
+ host->prev_cmd_code = req->cmd->opcode;
+
host->req = NULL;
host->cmd = NULL;
host->data = NULL;
@@ -553,7 +556,6 @@ static int imxmci_cpu_driven_data(struct imxmci_host *host, unsigned int *pstat)
{
int i;
int burst_len;
- int flush_len;
int trans_done = 0;
unsigned int stat = *pstat;
@@ -566,44 +568,43 @@ static int imxmci_cpu_driven_data(struct imxmci_host *host, unsigned int *pstat)
dev_dbg(mmc_dev(host->mmc), "imxmci_cpu_driven_data running STATUS = 0x%x\n",
stat);
+ udelay(20); /* required for clocks < 8MHz*/
+
if(host->dma_dir == DMA_FROM_DEVICE) {
imxmci_busy_wait_for_status(host, &stat,
STATUS_APPL_BUFF_FF | STATUS_DATA_TRANS_DONE,
- 20, "imxmci_cpu_driven_data read");
+ 50, "imxmci_cpu_driven_data read");
while((stat & (STATUS_APPL_BUFF_FF | STATUS_DATA_TRANS_DONE)) &&
- (host->data_cnt < host->dma_size)) {
- if(burst_len >= host->dma_size - host->data_cnt) {
- flush_len = burst_len;
- burst_len = host->dma_size - host->data_cnt;
- flush_len -= burst_len;
- host->data_cnt = host->dma_size;
- trans_done = 1;
- } else {
- flush_len = 0;
- host->data_cnt += burst_len;
- }
+ (host->data_cnt < 512)) {
+
+ udelay(20); /* required for clocks < 8MHz*/
for(i = burst_len; i>=2 ; i-=2) {
- *(host->data_ptr++) = MMC_BUFFER_ACCESS;
- udelay(20); /* required for clocks < 8MHz*/
+ u16 data;
+ data = MMC_BUFFER_ACCESS;
+ udelay(10); /* required for clocks < 8MHz*/
+ if(host->data_cnt+2 <= host->dma_size) {
+ *(host->data_ptr++) = data;
+ } else {
+ if(host->data_cnt < host->dma_size)
+ *(u8*)(host->data_ptr) = data;
+ }
+ host->data_cnt += 2;
}
- if(i == 1)
- *(u8*)(host->data_ptr) = MMC_BUFFER_ACCESS;
-
stat = MMC_STATUS;
- /* Flush extra bytes from FIFO */
- while(flush_len && !(stat & STATUS_DATA_TRANS_DONE)){
- i = MMC_BUFFER_ACCESS;
- stat = MMC_STATUS;
- stat &= ~STATUS_CRC_READ_ERR; /* Stupid but required there */
- }
-
- dev_dbg(mmc_dev(host->mmc), "imxmci_cpu_driven_data read burst %d STATUS = 0x%x\n",
- burst_len, stat);
+ dev_dbg(mmc_dev(host->mmc), "imxmci_cpu_driven_data read %d burst %d STATUS = 0x%x\n",
+ host->data_cnt, burst_len, stat);
}
+
+ if((stat & STATUS_DATA_TRANS_DONE) && (host->data_cnt >= 512))
+ trans_done = 1;
+
+ if(host->dma_size & 0x1ff)
+ stat &= ~STATUS_CRC_READ_ERR;
+
} else {
imxmci_busy_wait_for_status(host, &stat,
STATUS_APPL_BUFF_FE,
@@ -692,8 +693,8 @@ static void imxmci_tasklet_fnc(unsigned long data)
what, stat, MMC_INT_MASK);
dev_err(mmc_dev(host->mmc), "CMD_DAT_CONT = 0x%04x, MMC_BLK_LEN = 0x%04x, MMC_NOB = 0x%04x, DMA_CCR = 0x%08x\n",
MMC_CMD_DAT_CONT, MMC_BLK_LEN, MMC_NOB, CCR(host->dma));
- dev_err(mmc_dev(host->mmc), "CMD%d, bus %d-bit, dma_size = 0x%x\n",
- host->cmd?host->cmd->opcode:0, 1<<host->actual_bus_width, host->dma_size);
+ dev_err(mmc_dev(host->mmc), "CMD%d, prevCMD%d, bus %d-bit, dma_size = 0x%x\n",
+ host->cmd?host->cmd->opcode:0, host->prev_cmd_code, 1<<host->actual_bus_width, host->dma_size);
}
if(!host->present || timeout)