Skip to content

Commit

Permalink
mmc: atmel-mci: the r/w proof capability lack was not well managed
Browse files Browse the repository at this point in the history 
First mci IPs (mainly on rm9200 and 9261) don't have the r/w proof
capability.  The driver didn't work correctly without this capability
in PDC mode because of the double buffer switch which is too slow
even if we stop the transfer to perform this switch.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
  • Loading branch information
Ludovic Desroches authored and Chris Ball committed May 17, 2012
1 parent 705ad04 commit 7a90dcc
Showing 1 changed file with 78 additions and 14 deletions.
92 changes: 78 additions & 14 deletions drivers/mmc/host/atmel-mci.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -91,6 +91,11 @@ struct atmel_mci_dma {
* @regs: Pointer to MMIO registers.
* @sg: Scatterlist entry currently being processed by PIO or PDC code.
* @pio_offset: Offset into the current scatterlist entry.
* @buffer: Buffer used if we don't have the r/w proof capability. We
* don't have the time to switch pdc buffers so we have to use only
* one buffer for the full transaction.
* @buf_size: size of the buffer.
* @phys_buf_addr: buffer address needed for pdc.
* @cur_slot: The slot which is currently using the controller.
* @mrq: The request currently being processed on @cur_slot,
* or NULL if the controller is idle.
Expand Down Expand Up @@ -166,6 +171,9 @@ struct atmel_mci {

struct scatterlist *sg;
unsigned int pio_offset;
unsigned int *buffer;
unsigned int buf_size;
dma_addr_t buf_phys_addr;

struct atmel_mci_slot *cur_slot;
struct mmc_request *mrq;
Expand Down Expand Up @@ -480,6 +488,11 @@ static void atmci_init_debugfs(struct atmel_mci_slot *slot)
dev_err(&mmc->class_dev, "failed to initialize debugfs for slot\n");
}

static inline unsigned int atmci_get_version(struct atmel_mci *host)
{
return atmci_readl(host, ATMCI_VERSION) & 0x00000fff;
}

static inline unsigned int atmci_ns_to_clocks(struct atmel_mci *host,
unsigned int ns)
{
Expand Down Expand Up @@ -603,6 +616,7 @@ static void atmci_pdc_set_single_buf(struct atmel_mci *host,
enum atmci_xfer_dir dir, enum atmci_pdc_buf buf_nb)
{
u32 pointer_reg, counter_reg;
unsigned int buf_size;

if (dir == XFER_RECEIVE) {
pointer_reg = ATMEL_PDC_RPR;
Expand All @@ -617,8 +631,15 @@ static void atmci_pdc_set_single_buf(struct atmel_mci *host,
counter_reg += ATMEL_PDC_SCND_BUF_OFF;
}

atmci_writel(host, pointer_reg, sg_dma_address(host->sg));
if (host->data_size <= sg_dma_len(host->sg)) {
if (!host->caps.has_rwproof) {
buf_size = host->buf_size;
atmci_writel(host, pointer_reg, host->buf_phys_addr);
} else {
buf_size = sg_dma_len(host->sg);
atmci_writel(host, pointer_reg, sg_dma_address(host->sg));
}

if (host->data_size <= buf_size) {
if (host->data_size & 0x3) {
/* If size is different from modulo 4, transfer bytes */
atmci_writel(host, counter_reg, host->data_size);
Expand Down Expand Up @@ -670,7 +691,15 @@ static void atmci_pdc_cleanup(struct atmel_mci *host)
*/
static void atmci_pdc_complete(struct atmel_mci *host)
{
int transfer_size = host->data->blocks * host->data->blksz;

atmci_writel(host, ATMEL_PDC_PTCR, ATMEL_PDC_RXTDIS | ATMEL_PDC_TXTDIS);

if ((!host->caps.has_rwproof)
&& (host->data->flags & MMC_DATA_READ))
sg_copy_from_buffer(host->data->sg, host->data->sg_len,
host->buffer, transfer_size);

atmci_pdc_cleanup(host);

/*
Expand Down Expand Up @@ -818,6 +847,12 @@ atmci_prepare_data_pdc(struct atmel_mci *host, struct mmc_data *data)
/* Configure PDC */
host->data_size = data->blocks * data->blksz;
sg_len = dma_map_sg(&host->pdev->dev, data->sg, data->sg_len, dir);

if ((!host->caps.has_rwproof)
&& (host->data->flags & MMC_DATA_WRITE))
sg_copy_to_buffer(host->data->sg, host->data->sg_len,
host->buffer, host->data_size);

if (host->data_size)
atmci_pdc_set_both_buf(host,
((dir == DMA_FROM_DEVICE) ? XFER_RECEIVE : XFER_TRANSMIT));
Expand Down Expand Up @@ -1877,13 +1912,26 @@ static int __init atmci_init_slot(struct atmel_mci *host,
mmc->caps |= MMC_CAP_SDIO_IRQ;
if (host->caps.has_highspeed)
mmc->caps |= MMC_CAP_SD_HIGHSPEED;
if (slot_data->bus_width >= 4)
/*
* Without the read/write proof capability, it is strongly suggested to
* use only one bit for data to prevent fifo underruns and overruns
* which will corrupt data.
*/
if ((slot_data->bus_width >= 4) && host->caps.has_rwproof)
mmc->caps |= MMC_CAP_4_BIT_DATA;

mmc->max_segs = 64;
mmc->max_req_size = 32768 * 512;
mmc->max_blk_size = 32768;
mmc->max_blk_count = 512;
if (atmci_get_version(host) < 0x200) {
mmc->max_segs = 256;
mmc->max_blk_size = 4095;
mmc->max_blk_count = 256;
mmc->max_req_size = mmc->max_blk_size * mmc->max_blk_count;
mmc->max_seg_size = mmc->max_blk_size * mmc->max_segs;
} else {
mmc->max_segs = 64;
mmc->max_req_size = 32768 * 512;
mmc->max_blk_size = 32768;
mmc->max_blk_count = 512;
}

/* Assume card is present initially */
set_bit(ATMCI_CARD_PRESENT, &slot->flags);
Expand Down Expand Up @@ -2007,11 +2055,6 @@ static bool atmci_configure_dma(struct atmel_mci *host)
}
}

static inline unsigned int atmci_get_version(struct atmel_mci *host)
{
return atmci_readl(host, ATMCI_VERSION) & 0x00000fff;
}

/*
* HSMCI (High Speed MCI) module is not fully compatible with MCI module.
* HSMCI provides DMA support and a new config register but no more supports
Expand Down Expand Up @@ -2138,21 +2181,38 @@ static int __init atmci_probe(struct platform_device *pdev)
if (pdata->slot[0].bus_width) {
ret = atmci_init_slot(host, &pdata->slot[0],
0, ATMCI_SDCSEL_SLOT_A, ATMCI_SDIOIRQA);
if (!ret)
if (!ret) {
nr_slots++;
host->buf_size = host->slot[0]->mmc->max_req_size;
}
}
if (pdata->slot[1].bus_width) {
ret = atmci_init_slot(host, &pdata->slot[1],
1, ATMCI_SDCSEL_SLOT_B, ATMCI_SDIOIRQB);
if (!ret)
if (!ret) {
nr_slots++;
if (host->slot[1]->mmc->max_req_size > host->buf_size)
host->buf_size =
host->slot[1]->mmc->max_req_size;
}
}

if (!nr_slots) {
dev_err(&pdev->dev, "init failed: no slot defined\n");
goto err_init_slot;
}

if (!host->caps.has_rwproof) {
host->buffer = dma_alloc_coherent(&pdev->dev, host->buf_size,
&host->buf_phys_addr,
GFP_KERNEL);
if (!host->buffer) {
ret = -ENOMEM;
dev_err(&pdev->dev, "buffer allocation failed\n");
goto err_init_slot;
}
}

dev_info(&pdev->dev,
"Atmel MCI controller at 0x%08lx irq %d, %u slots\n",
host->mapbase, irq, nr_slots);
Expand All @@ -2179,6 +2239,10 @@ static int __exit atmci_remove(struct platform_device *pdev)

platform_set_drvdata(pdev, NULL);

if (host->buffer)
dma_free_coherent(&pdev->dev, host->buf_size,
host->buffer, host->buf_phys_addr);

for (i = 0; i < ATMCI_MAX_NR_SLOTS; i++) {
if (host->slot[i])
atmci_cleanup_slot(host->slot[i], i);
Expand Down

0 comments on commit 7a90dcc

Please sign in to comment.