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software/liblitedram: fix write leveling for x4 modules

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When using x4 modules, their response makes up only half a byte.
We need to extract the nibble and then test it.

Signed-off-by: Michal Sieron <msieron@antmicro.com>
This commit is contained in:
Michal Sieron 2022-12-20 15:38:57 +01:00
parent d67a7b13ae
commit 881bdbbbef
1 changed files with 8 additions and 1 deletions
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9
litex/soc/software/liblitedram/sdram.c
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@ -644,7 +644,14 @@ static int sdram_write_leveling_scan(int *delays, int loops, int show)
cdelay(100); cdelay(100);
csr_rd_buf_uint8(sdram_dfii_pix_rddata_addr(0), buf, DFII_PIX_DATA_BYTES); csr_rd_buf_uint8(sdram_dfii_pix_rddata_addr(0), buf, DFII_PIX_DATA_BYTES);
#if SDRAM_PHY_DQ_DQS_RATIO == 4 #if SDRAM_PHY_DQ_DQS_RATIO == 4
if (buf[SDRAM_PHY_MODULES-1-(i/2)] != 0) /* For x4 memories, we need to test individual nibbles, not bytes */
/* Extract the byte containing the nibble from the tested module */
int module_byte = buf[SDRAM_PHY_MODULES-1-(i/2)];
/* Shift the byte by 4 bits right if the module number is odd */
module_byte >>= 4 * (i % 2);
/* Extract the nibble from the tested module */
if ((module_byte & 0xf) != 0)
#else #else
if (buf[SDRAM_PHY_MODULES-1-i] != 0) if (buf[SDRAM_PHY_MODULES-1-i] != 0)
#endif #endif