[PATCH] ARM: imx: Fix problem with imx_ddrc_sdram_size

[Joacim Zetterling]

The imx8mn has a 16-bit SDRAM bus width access but the calculation
of the memory size treat it as a 32-bit width bus which makes the
memory calculation to be wrong (meminfo wrong and memtest fails).

There is a difference between the imx7 and the imx8 familys.
The imx8 family has a device config field in the master register of
the DDRC controller which the imx7 family doesn't have (the bus width
is 32-bit as default).

The device config field together with the DQ configuration tells us
the actual bus width of the device for a correct mem size calculaton.

>From the imx8mn reference manual:
+----------------------------------------------------+
|    Field      |     Function                       |
|----------------------------------------------------|
|    31-30      | Indicates the configuration of the |
|               | device used in the system.         |
| device_config |     00b - x4 device                |
|               |     01b - x8 device                |
|               |     10b - x16 device               |
|               |     11b - x32 device               |
+----------------------------------------------------+
...
...

Tested on the IMX8MN Evk with 2GB DDR4 and on a IMX8MN custom board
with 2GB LPDDR4, checked size and made memory test.

Signed-off-by: Joacim Zetterling <joacim.zetterling at westermo.com>
---
 arch/arm/mach-imx/esdctl.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/arch/arm/mach-imx/esdctl.c b/arch/arm/mach-imx/esdctl.c
index e56da3cb76d4..f80d94f2fca0 100644
--- a/arch/arm/mach-imx/esdctl.c
+++ b/arch/arm/mach-imx/esdctl.c
@@ -320,6 +320,7 @@ static int vf610_ddrmc_add_mem(void *mmdcbase, struct imx_esdctl_data *data)
 #define DDRC_MSTR_LPDDR4			BIT(5)
 #define DDRC_MSTR_DATA_BUS_WIDTH		GENMASK(13, 12)
 #define DDRC_MSTR_ACTIVE_RANKS			GENMASK(27, 24)
+#define DDRC_MSTR_DEVICE_CONFIG		GENMASK(31, 30)
 
 #define DDRC_ADDRMAP0_CS_BIT1			GENMASK(12,  8)
 
@@ -361,7 +362,7 @@ static resource_size_t
 imx_ddrc_sdram_size(void __iomem *ddrc, const u32 addrmap[],
 		    u8 col_max, const u8 col_b[], unsigned int col_b_num,
 		    u8 row_max, const u8 row_b[], unsigned int row_b_num,
-		    bool reduced_adress_space)
+		    bool reduced_adress_space, bool is_imx8)
 {
 	const u32 mstr = readl(ddrc + DDRC_MSTR);
 	unsigned int banks, ranks, columns, rows, active_ranks, width;
@@ -384,15 +385,20 @@ imx_ddrc_sdram_size(void __iomem *ddrc, const u32 addrmap[],
 		BUG();
 	}
 
+	if (is_imx8)
+		width = (1 << FIELD_GET(DDRC_MSTR_DEVICE_CONFIG, mstr)) >> 1;
+	else
+		width = 4;
+
 	switch (FIELD_GET(DDRC_MSTR_DATA_BUS_WIDTH, mstr)) {
 	case 0b00:	/* Full DQ bus  */
 		width = 4;
 		break;
 	case 0b01:      /* Half DQ bus  */
-		width = 2;
+		width >>= 1;
 		break;
 	case 0b10:	/* Quarter DQ bus  */
-		width = 1;
+		width >>= 2;
 		break;
 	default:
 		BUG();
@@ -466,7 +472,7 @@ static resource_size_t imx8m_ddrc_sdram_size(void __iomem *ddrc)
 	return imx_ddrc_sdram_size(ddrc, addrmap,
 				   12, ARRAY_AND_SIZE(col_b),
 				   16, ARRAY_AND_SIZE(row_b),
-				   reduced_adress_space);
+				   reduced_adress_space, true);
 }
 
 static int imx8m_ddrc_add_mem(void *mmdcbase, struct imx_esdctl_data *data)
@@ -508,7 +514,7 @@ static resource_size_t imx7d_ddrc_sdram_size(void __iomem *ddrc)
 	return imx_ddrc_sdram_size(ddrc, addrmap,
 				   11, ARRAY_AND_SIZE(col_b),
 				   15, ARRAY_AND_SIZE(row_b),
-				   reduced_adress_space);
+				   reduced_adress_space, false);
 }
 
 static int imx7d_ddrc_add_mem(void *mmdcbase, struct imx_esdctl_data *data)
-- 
2.25.1