From c49836f05aa15282f7280e06ede3f6f8a6324833 Mon Sep 17 00:00:00 2001 From: Miquel Raynal Date: Mon, 8 Apr 2019 09:41:46 +0200 Subject: [PATCH] mtd: rawnand: sunxi: Add A23/A33 DMA support 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, * drive SRAM accesses through the AHB bus instead of the MBUS. Signed-off-by: Miquel Raynal --- drivers/mtd/nand/raw/sunxi_nand.c | 38 ++++++++++++++++++++++++++++++++++++-- 1 file changed, 36 insertions(+), 2 deletions(-) diff --git a/drivers/mtd/nand/raw/sunxi_nand.c b/drivers/mtd/nand/raw/sunxi_nand.c index e93f39bc..b021a57 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 @@ -204,10 +205,14 @@ 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. * + * @sram_through_ahb: On A23, we choose to access the internal RAM through AHB + * instead of MBUS (less configuration). A10, A10s, A13 and + * A20 use the MBUS but no extra configuration is needed. * @reg_io_data: I/O data register * @dma_maxburst: DMA maxburst */ struct sunxi_nfc_caps { + bool sram_through_ahb; unsigned int reg_io_data; unsigned int dma_maxburst; }; @@ -363,10 +368,29 @@ static int sunxi_nfc_dma_op_prepare(struct sunxi_nfc *nfc, const void *buf, goto err_unmap_buf; } - writel(readl(nfc->regs + NFC_REG_CTL) | NFC_RAM_METHOD, - nfc->regs + NFC_REG_CTL); + /* + * On A23, we suppose the "internal RAM" (p.12 of the NFC user manual) + * refers to the NAND controller's internal SRAM. This memory is mapped + * and so is accessible from the AHB. It seems that it can also be + * accessed by the MBUS. MBUS accesses are mandatory when using the + * internal DMA instead of the external DMA engine. + * + * During DMA I/O operation, either we access this memory from the AHB + * by clearing the NFC_RAM_METHOD bit, or we set the bit and use the + * MBUS. In this case, we should also configure the MBUS DMA length + * NFC_REG_MDMA_CNT(0xC4) to be chunksize * nchunks. NAND I/O over MBUS + * are also limited to 32kiB pages. + */ + if (nfc->caps->sram_through_ahb) + writel(readl(nfc->regs + NFC_REG_CTL) & ~NFC_RAM_METHOD, + nfc->regs + NFC_REG_CTL); + else + writel(readl(nfc->regs + NFC_REG_CTL) | NFC_RAM_METHOD, + nfc->regs + NFC_REG_CTL); + writel(nchunks, nfc->regs + NFC_REG_SECTOR_NUM); writel(chunksize, nfc->regs + NFC_REG_CNT); + dmat = dmaengine_submit(dmad); ret = dma_submit_error(dmat); @@ -2175,11 +2199,21 @@ static const struct sunxi_nfc_caps sunxi_nfc_a10_caps = { .dma_maxburst = 4, }; +static const struct sunxi_nfc_caps sunxi_nfc_a23_caps = { + .sram_through_ahb = 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); -- 2.7.4