Aspeed hardware allows for acceessing the SDRAM from the host. SDRAM registers are located at the memory range at [0x80000000, 0xffffffff].
Refer to memory access with the macro AST_SDRAM(). Also add a TODO item for the nonsensical documentation next to its caller. Signed-off-by: Thomas Zimmermann <[email protected]> --- drivers/gpu/drm/ast/ast_2500.c | 17 ++++++++++------- drivers/gpu/drm/ast/ast_reg.h | 7 +++++++ 2 files changed, 17 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/ast/ast_2500.c b/drivers/gpu/drm/ast/ast_2500.c index f0639f1ef062..39f401dd1f47 100644 --- a/drivers/gpu/drm/ast/ast_2500.c +++ b/drivers/gpu/drm/ast/ast_2500.c @@ -225,6 +225,9 @@ static void ddr_phy_init_2500(struct ast_device *ast) } /* + * TODO: Review and fix the comments. The function below only detects + * up to 1 GiB of SDRAM. + * * Check DRAM Size * 1Gb : 0x80000000 ~ 0x87FFFFFF * 2Gb : 0x80000000 ~ 0x8FFFFFFF @@ -238,21 +241,21 @@ static void check_dram_size_2500(struct ast_device *ast, u32 tRFC) reg_04 = ast_mindwm(ast, AST_REG_MCR04) & 0xfffffffc; reg_14 = ast_mindwm(ast, AST_REG_MCR14) & 0xffffff00; - ast_moutdwm(ast, 0xA0100000, 0x41424344); - ast_moutdwm(ast, 0x90100000, 0x35363738); - ast_moutdwm(ast, 0x88100000, 0x292A2B2C); - ast_moutdwm(ast, 0x80100000, 0x1D1E1F10); + ast_moutdwm(ast, AST_SDRAM(0x20100000), 0x41424344); + ast_moutdwm(ast, AST_SDRAM(0x10100000), 0x35363738); + ast_moutdwm(ast, AST_SDRAM(0x08100000), 0x292A2B2C); + ast_moutdwm(ast, AST_SDRAM(0x00100000), 0x1D1E1F10); /* Check 8Gbit */ - if (ast_mindwm(ast, 0xA0100000) == 0x41424344) { + if (ast_mindwm(ast, AST_SDRAM(0x20100000)) == 0x41424344) { reg_04 |= 0x03; reg_14 |= (tRFC >> 24) & 0xFF; /* Check 4Gbit */ - } else if (ast_mindwm(ast, 0x90100000) == 0x35363738) { + } else if (ast_mindwm(ast, AST_SDRAM(0x10100000)) == 0x35363738) { reg_04 |= 0x02; reg_14 |= (tRFC >> 16) & 0xFF; /* Check 2Gbit */ - } else if (ast_mindwm(ast, 0x88100000) == 0x292A2B2C) { + } else if (ast_mindwm(ast, AST_SDRAM(0x08100000)) == 0x292A2B2C) { reg_04 |= 0x01; reg_14 |= (tRFC >> 8) & 0xFF; } else { diff --git a/drivers/gpu/drm/ast/ast_reg.h b/drivers/gpu/drm/ast/ast_reg.h index 5effe6897b51..78fabe2a9c81 100644 --- a/drivers/gpu/drm/ast/ast_reg.h +++ b/drivers/gpu/drm/ast/ast_reg.h @@ -209,4 +209,11 @@ #define AST_REG_WDT1C(__n) AST_REG_WDT((__n), 0x1c) #define AST_REG_WDT2C(__n) AST_REG_WDT((__n), 0x2c) +/* + * SDRAM (0x80000000 - 0xffffffff) + */ + +#define AST_SDRAM_BASE (0x80000000) +#define AST_SDRAM(__offset) (AST_SDRAM_BASE + (__offset)) + #endif -- 2.53.0
