mmc: mxcmmc: enable DMA support on mpc512x
Add SDHC DMA channel description to the mpc512x device tree to enable
slave channel requesting in the mxcmmc driver.
mpc512x DMA engine doesn't support endianness conversion when
reading/writing data from peripheral's FIFO, so we have to swap data
buffers before each DMA write and after each DMA read transfer manually.
Since chained SDHC DMA transfers are not supported on mpc512x, limit
'max_segs' tunable parameter to one and initialise it to 64 only when
running on i.MX platforms.
Signed-off-by: Anatolij Gustschin <agust@denx.de>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/drivers/mmc/host/mxcmmc.c b/drivers/mmc/host/mxcmmc.c
index 5d52826..d503635 100644
--- a/drivers/mmc/host/mxcmmc.c
+++ b/drivers/mmc/host/mxcmmc.c
@@ -301,6 +301,29 @@
}
static int mxcmci_setup_dma(struct mmc_host *mmc);
+#if IS_ENABLED(CONFIG_PPC_MPC512x)
+static inline void buffer_swap32(u32 *buf, int len)
+{
+ int i;
+
+ for (i = 0; i < ((len + 3) / 4); i++) {
+ st_le32(buf, *buf);
+ buf++;
+ }
+}
+
+static void mxcmci_swap_buffers(struct mmc_data *data)
+{
+ struct scatterlist *sg;
+ int i;
+
+ for_each_sg(data->sg, sg, data->sg_len, i)
+ buffer_swap32(sg_virt(sg), sg->length);
+}
+#else
+static inline void mxcmci_swap_buffers(struct mmc_data *data) {}
+#endif
+
static int mxcmci_setup_data(struct mxcmci_host *host, struct mmc_data *data)
{
unsigned int nob = data->blocks;
@@ -336,6 +359,8 @@
} else {
host->dma_dir = DMA_TO_DEVICE;
slave_dirn = DMA_MEM_TO_DEV;
+
+ mxcmci_swap_buffers(data);
}
nents = dma_map_sg(host->dma->device->dev, data->sg,
@@ -461,9 +486,11 @@
struct mmc_data *data = host->data;
int data_error;
- if (mxcmci_use_dma(host))
+ if (mxcmci_use_dma(host)) {
dma_unmap_sg(host->dma->device->dev, data->sg, data->sg_len,
host->dma_dir);
+ mxcmci_swap_buffers(data);
+ }
if (stat & STATUS_ERR_MASK) {
dev_dbg(mmc_dev(host->mmc), "request failed. status: 0x%08x\n",
@@ -1050,7 +1077,6 @@
mmc->caps |= MMC_CAP_SDIO_IRQ;
/* MMC core transfer sizes tunable parameters */
- mmc->max_segs = 64;
mmc->max_blk_size = 2048;
mmc->max_blk_count = 65535;
mmc->max_req_size = mmc->max_blk_size * mmc->max_blk_count;
@@ -1069,6 +1095,11 @@
} else {
host->devtype = pdev->id_entry->driver_data;
}
+
+ /* adjust max_segs after devtype detection */
+ if (!is_mpc512x_mmc(host))
+ mmc->max_segs = 64;
+
host->mmc = mmc;
host->pdata = pdata;
spin_lock_init(&host->lock);