struct mmc_data *data = mrq->data;
struct scatterlist *sg;
int i;
- bool use_desc_chain_mode = true;
/*
* When Controller DMA cannot directly access DDR memory, disable
if (host->dram_access_quirk)
return;
- /*
- * Broken SDIO with AP6255-based WiFi on Khadas VIM Pro has been
- * reported. For some strange reason this occurs in descriptor
- * chain mode only. So let's fall back to bounce buffer mode
- * for command SD_IO_RW_EXTENDED.
- */
- if (mrq->cmd->opcode == SD_IO_RW_EXTENDED)
- return;
+ if (data->blocks > 1) {
+ /*
+ * In block mode DMA descriptor format, "length" field indicates
+ * number of blocks and there is no way to pass DMA size that
+ * is not multiple of SDIO block size, making it impossible to
+ * tie more than one memory buffer with single SDIO block.
+ * Block mode sg buffer size should be aligned with SDIO block
+ * size, otherwise chain mode could not be used.
+ */
+ for_each_sg(data->sg, sg, data->sg_len, i) {
+ if (sg->length % data->blksz) {
+ WARN_ONCE(1, "unaligned sg len %u blksize %u\n",
+ sg->length, data->blksz);
+ return;
+ }
+ }
+ }
- for_each_sg(data->sg, sg, data->sg_len, i)
+ for_each_sg(data->sg, sg, data->sg_len, i) {
/* check for 8 byte alignment */
- if (sg->offset & 7) {
+ if (sg->offset % 8) {
WARN_ONCE(1, "unaligned scatterlist buffer\n");
- use_desc_chain_mode = false;
- break;
+ return;
}
+ }
- if (use_desc_chain_mode)
- data->host_cookie |= SD_EMMC_DESC_CHAIN_MODE;
+ data->host_cookie |= SD_EMMC_DESC_CHAIN_MODE;
}
static inline bool meson_mmc_desc_chain_mode(const struct mmc_data *data)