mtd: rawnand: sunxi: Add A23/A33 DMA support with extra MBUS configuration

Allwinner NAND controllers can make use of DMA to enhance the I/O
throughput thanks to ECC pipelining. DMA handling with A23/A33 NAND IP
is a bit different than with the older SoCs, hence the introduction of
a new compatible to handle:
* the differences between register offsets,
* the burst length change from 4 to minimum 8,
* manage SRAM accesses through MBUS with extra configuration.

Fixes: c49836f05aa1 ("mtd: rawnand: sunxi: Add A23/A33 DMA support")
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/drivers/mtd/nand/raw/sunxi_nand.c b/drivers/mtd/nand/raw/sunxi_nand.c
index e93f39bc2bc5..89773293c64d 100644
--- a/drivers/mtd/nand/raw/sunxi_nand.c
+++ b/drivers/mtd/nand/raw/sunxi_nand.c
@@ -43,6 +43,7 @@
 #define NFC_REG_RCMD_SET        0x0028
 #define NFC_REG_WCMD_SET        0x002C
 #define NFC_REG_A10_IO_DATA     0x0030
+#define NFC_REG_A23_IO_DATA     0x0300
 #define NFC_REG_ECC_CTL         0x0034
 #define NFC_REG_ECC_ST          0x0038
 #define NFC_REG_DEBUG           0x003C
@@ -50,6 +51,7 @@
 #define NFC_REG_USER_DATA(x)    (0x0050 + ((x) * 4))
 #define NFC_REG_SPARE_AREA      0x00A0
 #define NFC_REG_PAT_ID          0x00A4
+#define NFC_REG_MDMA_CNT        0x00C4
 #define NFC_RAM0_BASE           0x0400
 #define NFC_RAM1_BASE           0x0800
 
@@ -68,6 +70,7 @@
 #define NFC_PAGE_SHIFT(x)       (((x) < 10 ? 0 : (x) - 10) << 8)
 #define NFC_SAM                 BIT(12)
 #define NFC_RAM_METHOD          BIT(14)
+#define NFC_DMA_TYPE_NORMAL     BIT(15)
 #define NFC_DEBUG_CTL           BIT(31)
 
 /* define bit use in NFC_ST */
@@ -204,10 +207,13 @@ static inline struct sunxi_nand_chip *to_sunxi_nand(struct nand_chip *nand)
  * NAND Controller capabilities structure: stores NAND controller capabilities
  * for distinction between compatible strings.
  *
+ * @extra_mbus_conf:    Contrary to A10, A10s and A13, accessing internal RAM
+ *                      through MBUS on A23/A33 needs extra configuration.
  * @reg_io_data:        I/O data register
  * @dma_maxburst:       DMA maxburst
  */
 struct sunxi_nfc_caps {
+        bool extra_mbus_conf;
         unsigned int reg_io_data;
         unsigned int dma_maxburst;
 };
@@ -367,6 +373,9 @@ static int sunxi_nfc_dma_op_prepare(struct sunxi_nfc *nfc, const void *buf,
                nfc->regs + NFC_REG_CTL);
         writel(nchunks, nfc->regs + NFC_REG_SECTOR_NUM);
         writel(chunksize, nfc->regs + NFC_REG_CNT);
+        if (nfc->caps->extra_mbus_conf)
+                writel(chunksize * nchunks, nfc->regs + NFC_REG_MDMA_CNT);
+
         dmat = dmaengine_submit(dmad);
 
         ret = dma_submit_error(dmat);
@@ -2127,6 +2136,11 @@ static int sunxi_nfc_probe(struct platform_device *pdev)
                 dmac_cfg.src_maxburst = nfc->caps->dma_maxburst;
                 dmac_cfg.dst_maxburst = nfc->caps->dma_maxburst;
                 dmaengine_slave_config(nfc->dmac, &dmac_cfg);
+
+                if (nfc->caps->extra_mbus_conf)
+                        writel(readl(nfc->regs + NFC_REG_CTL) |
+                               NFC_DMA_TYPE_NORMAL, nfc->regs + NFC_REG_CTL);
+
         } else {
                 dev_warn(dev, "failed to request rxtx DMA channel\n");
         }
@@ -2175,11 +2189,21 @@ static const struct sunxi_nfc_caps sunxi_nfc_a10_caps = {
         .dma_maxburst = 4,
 };
 
+static const struct sunxi_nfc_caps sunxi_nfc_a23_caps = {
+        .extra_mbus_conf = true,
+        .reg_io_data = NFC_REG_A23_IO_DATA,
+        .dma_maxburst = 8,
+};
+
 static const struct of_device_id sunxi_nfc_ids[] = {
         {
                 .compatible = "allwinner,sun4i-a10-nand",
                 .data = &sunxi_nfc_a10_caps,
         },
+        {
+                .compatible = "allwinner,sun8i-a23-nand-controller",
+                .data = &sunxi_nfc_a23_caps,
+        },
         { /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, sunxi_nfc_ids);