s3cmci: DMA fixes

Fixes for the DMA transfer mode of the driver to try and improve the state
of the code:

- Ensure that dma_complete is set during the end of the command phase
  so that transfers do not stall awaiting the completion

- Update the DMA debugging to provide a bit more useful information
  such as how many DMA descriptors where not processed and print the
  DMA addresses in hexadecimal.

- Fix the DMA channel request code to actually request DMA for the
  S3CMCI block instead of whatever '0' signified.

- Add fallback to PIO if we cannot get the DMA channel, as many of the
  devices with this block only have a limited number of DMA channels.

- Only try and claim and free the DMA channel if we are trying to use it.

This improves the driver DMA code to the point where it can now identify a
card and read the partition table.  However the DMA can still stall when
trying to move data between the host and memory.

Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Ben Dooks 2009-10-01 15:44:19 -07:00 committed by Linus Torvalds
parent 26f14947db
commit 68c5ed592f
2 changed files with 47 additions and 18 deletions

View file

@ -183,6 +183,21 @@ static inline bool s3cmci_host_usedma(struct s3cmci_host *host)
#endif
}
/**
* s3cmci_host_canpio - return true if host has pio code available
*
* Return true if the driver has been compiled with the PIO support code
* available.
*/
static inline bool s3cmci_host_canpio(void)
{
#ifdef CONFIG_MMC_S3C_PIO
return true;
#else
return false;
#endif
}
static inline u32 enable_imask(struct s3cmci_host *host, u32 imask)
{
u32 newmask;
@ -786,6 +801,7 @@ static void s3cmci_dma_done_callback(struct s3c2410_dma_chan *dma_ch,
dbg(host, dbg_dma, "DMA FINISHED Size:%i DSTA:%08x DCNT:%08x\n",
size, mci_dsta, mci_dcnt);
host->dma_complete = 1;
host->complete_what = COMPLETION_FINALIZE;
out:
@ -816,7 +832,8 @@ static void finalize_request(struct s3cmci_host *host)
if (cmd->data && (cmd->error == 0) &&
(cmd->data->error == 0)) {
if (s3cmci_host_usedma(host) && (!host->dma_complete)) {
dbg(host, dbg_dma, "DMA Missing!\n");
dbg(host, dbg_dma, "DMA Missing (%d)!\n",
host->dma_complete);
return;
}
}
@ -1065,7 +1082,7 @@ static int s3cmci_prepare_pio(struct s3cmci_host *host, struct mmc_data *data)
static int s3cmci_prepare_dma(struct s3cmci_host *host, struct mmc_data *data)
{
int dma_len, i;
int rw = (data->flags & MMC_DATA_WRITE) ? 1 : 0;
int rw = data->flags & MMC_DATA_WRITE;
BUG_ON((data->flags & BOTH_DIR) == BOTH_DIR);
@ -1073,7 +1090,7 @@ static int s3cmci_prepare_dma(struct s3cmci_host *host, struct mmc_data *data)
s3c2410_dma_ctrl(host->dma, S3C2410_DMAOP_FLUSH);
dma_len = dma_map_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
(rw) ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
rw ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
if (dma_len == 0)
return -ENOMEM;
@ -1084,11 +1101,11 @@ static int s3cmci_prepare_dma(struct s3cmci_host *host, struct mmc_data *data)
for (i = 0; i < dma_len; i++) {
int res;
dbg(host, dbg_dma, "enqueue %i:%u@%u\n", i,
sg_dma_address(&data->sg[i]),
sg_dma_len(&data->sg[i]));
dbg(host, dbg_dma, "enqueue %i: %08x@%u\n", i,
sg_dma_address(&data->sg[i]),
sg_dma_len(&data->sg[i]));
res = s3c2410_dma_enqueue(host->dma, (void *) host,
res = s3c2410_dma_enqueue(host->dma, host,
sg_dma_address(&data->sg[i]),
sg_dma_len(&data->sg[i]));
@ -1581,8 +1598,6 @@ static int __devinit s3cmci_probe(struct platform_device *pdev)
host->complete_what = COMPLETION_NONE;
host->pio_active = XFER_NONE;
host->dma = S3CMCI_DMA;
#ifdef CONFIG_MMC_S3C_PIODMA
host->dodma = host->pdata->dma;
#endif
@ -1665,10 +1680,21 @@ static int __devinit s3cmci_probe(struct platform_device *pdev)
gpio_direction_input(host->pdata->gpio_wprotect);
}
if (s3c2410_dma_request(S3CMCI_DMA, &s3cmci_dma_client, NULL) < 0) {
dev_err(&pdev->dev, "unable to get DMA channel.\n");
ret = -EBUSY;
goto probe_free_gpio_wp;
/* depending on the dma state, get a dma channel to use. */
if (s3cmci_host_usedma(host)) {
host->dma = s3c2410_dma_request(DMACH_SDI, &s3cmci_dma_client,
host);
if (host->dma < 0) {
dev_err(&pdev->dev, "cannot get DMA channel.\n");
if (!s3cmci_host_canpio()) {
ret = -EBUSY;
goto probe_free_gpio_wp;
} else {
dev_warn(&pdev->dev, "falling back to PIO.\n");
host->dodma = 0;
}
}
}
host->clk = clk_get(&pdev->dev, "sdi");
@ -1676,7 +1702,7 @@ static int __devinit s3cmci_probe(struct platform_device *pdev)
dev_err(&pdev->dev, "failed to find clock source.\n");
ret = PTR_ERR(host->clk);
host->clk = NULL;
goto probe_free_host;
goto probe_free_dma;
}
ret = clk_enable(host->clk);
@ -1738,6 +1764,10 @@ static int __devinit s3cmci_probe(struct platform_device *pdev)
clk_free:
clk_put(host->clk);
probe_free_dma:
if (s3cmci_host_usedma(host))
s3c2410_dma_free(host->dma, &s3cmci_dma_client);
probe_free_gpio_wp:
if (host->pdata->gpio_wprotect)
gpio_free(host->pdata->gpio_wprotect);
@ -1796,7 +1826,9 @@ static int __devexit s3cmci_remove(struct platform_device *pdev)
clk_put(host->clk);
tasklet_disable(&host->pio_tasklet);
s3c2410_dma_free(S3CMCI_DMA, &s3cmci_dma_client);
if (s3cmci_host_usedma(host))
s3c2410_dma_free(host->dma, &s3cmci_dma_client);
free_irq(host->irq, host);

View file

@ -8,9 +8,6 @@
* published by the Free Software Foundation.
*/
/* FIXME: DMA Resource management ?! */
#define S3CMCI_DMA 0
enum s3cmci_waitfor {
COMPLETION_NONE,
COMPLETION_FINALIZE,