[PATCH RFC 03/15] sunxi: SPL SPI: add support for read command with 2 byte address

[John Watts]

From: Icenowy Zheng <uwu at icenowy.me>

This kind of read command is utilized in SPI NANDs for reading data
inside a selected page, which is obviously smaller than how much 2
byte address can address. So 2 bytes are used for the address and one
dummy byte is needed after the real address. As the address is sent out
in bit endian, this makes it not compatible with usual 3 byte address.

Signed-off-by: Icenowy Zheng <uwu at icenowy.me>
Reviewed-by: Samuel Holland <samuel at sholland.org>
Tested-by: Samuel Holland <samuel at sholland.org> # Orange Pi Zero Plus
---
 arch/arm/mach-sunxi/spl_spi_sunxi.c | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/arch/arm/mach-sunxi/spl_spi_sunxi.c b/arch/arm/mach-sunxi/spl_spi_sunxi.c
index e85ae96485..fe95878eae 100644
--- a/arch/arm/mach-sunxi/spl_spi_sunxi.c
+++ b/arch/arm/mach-sunxi/spl_spi_sunxi.c
@@ -344,7 +344,7 @@ static void spi0_xfer(const u8 *txbuf, u32 txlen, u8 *rxbuf, u32 rxlen)
 	}
 }
 
-static void spi0_read_data(void *buf, u32 addr, u32 len)
+static void spi0_read_data(void *buf, u32 addr, u32 len, u32 addr_len)
 {
 	u8 *buf8 = buf;
 	u32 chunk_len;
@@ -355,9 +355,15 @@ static void spi0_read_data(void *buf, u32 addr, u32 len)
 
 		/* Configure the Read Data Bytes (03h) command header */
 		txbuf[0] = 0x03;
-		txbuf[1] = (u8)(addr >> 16);
-		txbuf[2] = (u8)(addr >> 8);
-		txbuf[3] = (u8)(addr);
+		if (addr_len == 3) {
+			txbuf[1] = (u8)(addr >> 16);
+			txbuf[2] = (u8)(addr >> 8);
+			txbuf[3] = (u8)(addr);
+		} else if (addr_len == 2) {
+			txbuf[1] = (u8)(addr >> 8);
+			txbuf[2] = (u8)(addr);
+			txbuf[3] = 0; /* dummy */
+		}
 
 		if (chunk_len > SPI_READ_MAX_SIZE)
 			chunk_len = SPI_READ_MAX_SIZE;
@@ -376,7 +382,7 @@ static void spi0_read_data(void *buf, u32 addr, u32 len)
 static ulong spi_load_read(struct spl_load_info *load, ulong sector,
 			   ulong count, void *buf)
 {
-	spi0_read_data(buf, sector, count);
+	spi0_read_data(buf, sector, count, 3);
 
 	return count;
 }
@@ -395,7 +401,7 @@ static int spl_spi_load_image(struct spl_image_info *spl_image,
 
 	spi0_init();
 
-	spi0_read_data((void *)header, load_offset, 0x40);
+	spi0_read_data((void *)header, load_offset, 0x40, 3);
 
         if (IS_ENABLED(CONFIG_SPL_LOAD_FIT) &&
 		image_get_magic(header) == FDT_MAGIC) {
@@ -412,7 +418,7 @@ static int spl_spi_load_image(struct spl_image_info *spl_image,
 			return ret;
 
 		spi0_read_data((void *)spl_image->load_addr,
-			       load_offset, spl_image->size);
+			       load_offset, spl_image->size, 3);
 	}
 
 	spi0_deinit();

-- 
2.44.0