mmc: dw_mmc: Add desc_num field for clarity

The ring_size field in struct dw_mci is misleadingly named.
Despite its name, it does not represent the size of the descriptor
ring buffer in bytes, but rather the number of descriptors allocated
within the fixed-size ring buffer.

The actual ring buffer size is fixed at PAGE_SIZE (or DESC_RING_BUF_SZ,
which equals PAGE_SIZE). Within this buffer, we allocate either
struct idmac_desc or struct idmac_desc_64addr descriptors, and
ring_size stores the count of these descriptors.

This naming has caused confusion, as it's also used to set
mmc->max_segs (the maximum number of scatter-gather segments),
which logically corresponds to the number of descriptors, not a
size in bytes.

No functional change is introduced by this naming-only patch.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulfh@kernel.org>

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 3b4157f34d11f35858dae2c2202329e043ef5ade..d734d010444dd2036f1562e754551bcbf2dcf774 100644 (file)
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -490,12 +490,12 @@ static int dw_mci_idmac_init(struct dw_mci *host)
 
        if (host->dma_64bit_address == 1) {
                struct idmac_desc_64addr *p;
-               /* Number of descriptors in the ring buffer */
-               host->ring_size =
+
+               host->desc_num =
                        DESC_RING_BUF_SZ / sizeof(struct idmac_desc_64addr);
 
                /* Forward link the descriptor list */
-               for (i = 0, p = host->sg_cpu; i < host->ring_size - 1;
+               for (i = 0, p = host->sg_cpu; i < host->desc_num - 1;
                                                                i++, p++) {
                        p->des6 = (host->sg_dma +
                                        (sizeof(struct idmac_desc_64addr) *
@@ -518,13 +518,13 @@ static int dw_mci_idmac_init(struct dw_mci *host)
 
        } else {
                struct idmac_desc *p;
-               /* Number of descriptors in the ring buffer */
-               host->ring_size =
+
+               host->desc_num =
                        DESC_RING_BUF_SZ / sizeof(struct idmac_desc);
 
                /* Forward link the descriptor list */
                for (i = 0, p = host->sg_cpu;
-                    i < host->ring_size - 1;
+                    i < host->desc_num - 1;
                     i++, p++) {
                        p->des3 = cpu_to_le32(host->sg_dma +
                                        (sizeof(struct idmac_desc) * (i + 1)));
@@ -2857,10 +2857,10 @@ static int dw_mci_init_host(struct dw_mci *host)
 
        /* Useful defaults if platform data is unset. */
        if (host->use_dma == TRANS_MODE_IDMAC) {
-               mmc->max_segs = host->ring_size;
+               mmc->max_segs = host->desc_num;
                mmc->max_blk_size = 65535;
                mmc->max_seg_size = 0x1000;
-               mmc->max_req_size = mmc->max_seg_size * host->ring_size;
+               mmc->max_req_size = mmc->max_seg_size * host->desc_num;
                mmc->max_blk_count = mmc->max_req_size / 512;
        } else if (host->use_dma == TRANS_MODE_EDMAC) {
                mmc->max_segs = 64;

diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
index 2ce8585e2c1e5c085d95789c54427cbe8551362e..9ffcd3946cffb316d30de2ecb9c503920cc928b6 100644 (file)
--- a/drivers/mmc/host/dw_mmc.h
+++ b/drivers/mmc/host/dw_mmc.h
@@ -79,7 +79,7 @@ struct dw_mci_dma_slave {
  * @dma_ops: Pointer to DMA callbacks.
  * @cmd_status: Snapshot of SR taken upon completion of the current
  *     command. Only valid when EVENT_CMD_COMPLETE is pending.
- * @ring_size: Buffer size for idma descriptors.
+ * @desc_num: Number of idmac descriptors available.
  * @dms: structure of slave-dma private data.
  * @phy_regs: physical address of controller's register map
  * @data_status: Snapshot of SR taken upon completion of the current
@@ -186,7 +186,7 @@ struct dw_mci {
        void                    *sg_cpu;
        const struct dw_mci_dma_ops     *dma_ops;
        /* For idmac */
-       unsigned int            ring_size;
+       unsigned short          desc_num;
 
        /* For edmac */
        struct dw_mci_dma_slave *dms;