[PATCH v2 15/19] ARM: i.MX6: boot: Move magic numbers into utility functions

[Andrey Smirnov]

Move magic numbers and algorithm for determining Serial ROM bootsource
and boot instance into utility functions. Add a comment on the logic
behing the latter while at it.

Signed-off-by: Andrey Smirnov <andrew.smir...@gmail.com>
---
 arch/arm/mach-imx/boot.c | 67 ++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 53 insertions(+), 14 deletions(-)

diff --git a/arch/arm/mach-imx/boot.c b/arch/arm/mach-imx/boot.c
index 799d5ec93..60307ffb6 100644
--- a/arch/arm/mach-imx/boot.c
+++ b/arch/arm/mach-imx/boot.c
@@ -176,7 +176,9 @@ void imx51_get_boot_source(enum bootsource *src, int 
*instance)
 #define __BOOT_CFG(n, m, l)    GENMASK((m) + ((n) - 1) * 8, \
                                        (l) + ((n) - 1) * 8)
 #define BOOT_CFG1(m, l)                __BOOT_CFG(1, m, l)
+#define BOOT_CFG2(m, l)                __BOOT_CFG(2, m, l)
 #define BOOT_CFG3(m, l)                __BOOT_CFG(3, m, l)
+#define BOOT_CFG4(m, l)                __BOOT_CFG(4, m, l)
 
 #define ___BOOT_CFG(n, i)      __BOOT_CFG(n, i, i)
 #define __MAKE_BOOT_CFG_BITS(idx)                                      \
@@ -192,6 +194,8 @@ void imx51_get_boot_source(enum bootsource *src, int 
*instance)
        };
 
 __MAKE_BOOT_CFG_BITS(1)
+__MAKE_BOOT_CFG_BITS(2)
+__MAKE_BOOT_CFG_BITS(4)
 #undef __MAKE_BOOT_CFG
 #undef ___BOOT_CFG
 
@@ -287,12 +291,57 @@ static bool imx6_bootsource_serial(uint32_t sbmr2)
                !(sbmr2 & BT_FUSE_SEL));
 }
 
+static int __imx6_bootsource_serial_rom(uint32_t r)
+{
+       return FIELD_GET(BOOT_CFG4(2, 0), r);
+}
+
+/*
+ * Serial ROM bootsource on i.MX6 are as follows:
+ *
+ *     000 - ECSPI-1
+ *     001 - ECSPI-2
+ *     010 - ECSPI-3
+ *     011 - ECSPI-4
+ *     100 - ECSPI-5
+ *     101 - I2C1
+ *     110 - I2C2
+ *     111 - I2C3
+ *
+ * There's no single bit that would tell us we are booting from I2C or
+ * SPI, so we just have to compare the "source" agains the value for
+ * I2C1 for both: calculating bootsource and boot instance.
+ */
+#define IMX6_BOOTSOURCE_SERIAL_ROM_I2C1        0b101
+
+static enum bootsource imx6_bootsource_serial_rom(uint32_t sbmr)
+{
+       const int source = __imx6_bootsource_serial_rom(sbmr);
+
+       return source < IMX6_BOOTSOURCE_SERIAL_ROM_I2C1 ?
+               BOOTSOURCE_SPI : BOOTSOURCE_I2C;
+}
+
+static int imx6_boot_instance_serial_rom(uint32_t sbmr)
+{
+       const int source = __imx6_bootsource_serial_rom(sbmr);
+
+       if (source < IMX6_BOOTSOURCE_SERIAL_ROM_I2C1)
+               return source;
+
+       return source - IMX6_BOOTSOURCE_SERIAL_ROM_I2C1;
+}
+
+static int imx6_boot_instance_mmc(uint32_t r)
+{
+       return FIELD_GET(BOOT_CFG2(4, 3), r);
+}
+
 void imx6_get_boot_source(enum bootsource *src, int *instance)
 {
        void __iomem *src_base = IOMEM(MX6_SRC_BASE_ADDR);
        uint32_t sbmr1 = readl(src_base + IMX6_SRC_SBMR1);
        uint32_t sbmr2 = readl(src_base + IMX6_SRC_SBMR2);
-       uint32_t boot_cfg_4_2_0;
 
        if (imx6_bootsource_reserved(sbmr2))
                return;
@@ -307,25 +356,15 @@ void imx6_get_boot_source(enum bootsource *src, int 
*instance)
                *src = BOOTSOURCE_HD;
                break;
        case 3:
-               /* BOOT_CFG4[2:0] */
-               boot_cfg_4_2_0 = (sbmr1 >> 24) & 0x7;
-
-               if (boot_cfg_4_2_0 > 4) {
-                       *src = BOOTSOURCE_I2C;
-                       *instance = boot_cfg_4_2_0 - 5;
-               } else {
-                       *src = BOOTSOURCE_SPI;
-                       *instance = boot_cfg_4_2_0;
-               }
+               *src = imx6_bootsource_serial_rom(sbmr1);
+               *instance = imx6_boot_instance_serial_rom(sbmr1);
                break;
        case 4:
        case 5:
        case 6:
        case 7:
                *src = BOOTSOURCE_MMC;
-
-               /* BOOT_CFG2[4:3] */
-               *instance = (sbmr1 >> 11) & 0x3;
+               *instance = imx6_boot_instance_mmc(sbmr1);
                break;
        default:
                if (imx53_bootsource_nand(sbmr1))
-- 
2.14.3


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