[U-Boot] [RFC PATCH 3/8] sun8i: Add a macro to read the silicon revision

[Icenowy Zheng]

From: "tpearson at raptorengineering.com" <tpearson at raptorengineering.com>

According to the user manuals released by Allwinner, the low 8-bit of
the 0x24 register in "System Control" (marked SRAMC in U-Boot source as
it controls some SRAMs' functionality since A10) is the silicon revision
of the chip.

This data is now important for A83T: according to the BSP source A83T
have two revisions: Revision A (with revision ID 0) and Revision B (with
revision ID 1); and revision B requires a SMP bringup workaround.

Print the revision number when the SoC is A83T, as it does matter there.

Signed-off-by: Timothy Pearson <tpearson at raptorengineering.com>
[Icenowy: convert to macro so that it can be reused in PSCI code]
Signed-off-by: Icenowy Zheng <icenowy at aosc.io>
---
 arch/arm/include/asm/arch-sunxi/cpu_sun4i.h | 7 +++++++
 arch/arm/mach-sunxi/cpu_info.c              | 2 +-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/arch-sunxi/cpu_sun4i.h b/arch/arm/include/asm/arch-sunxi/cpu_sun4i.h
index 6aa5e91ada..a96680d8e8 100644
--- a/arch/arm/include/asm/arch-sunxi/cpu_sun4i.h
+++ b/arch/arm/include/asm/arch-sunxi/cpu_sun4i.h
@@ -205,6 +205,13 @@ void sunxi_board_init(void);
 void sunxi_reset(void);
 int sunxi_get_ss_bonding_id(void);
 int sunxi_get_sid(unsigned int *sid);
+
+/*
+ * Implement it as a macro, because it's used both in PSCI source code
+ * and normal U-Boot source code.
+ */
+#define sunxi_get_revision() (readl(SUNXI_SRAMC_BASE + 0x24) & 0xff)
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* _SUNXI_CPU_SUN4I_H */
diff --git a/arch/arm/mach-sunxi/cpu_info.c b/arch/arm/mach-sunxi/cpu_info.c
index 25a5ec26a0..4236ab8f11 100644
--- a/arch/arm/mach-sunxi/cpu_info.c
+++ b/arch/arm/mach-sunxi/cpu_info.c
@@ -84,7 +84,7 @@ int print_cpuinfo(void)
 #elif defined CONFIG_MACH_SUN8I_A33
 	printf("CPU:   Allwinner A33 (SUN8I %04x)\n", sunxi_get_sram_id());
 #elif defined CONFIG_MACH_SUN8I_A83T
-	printf("CPU:   Allwinner A83T (SUN8I %04x)\n", sunxi_get_sram_id());
+	printf("CPU:   Allwinner A83T (SUN8I %04x rev. %x)\n", sunxi_get_sram_id(), sunxi_get_revision());
 #elif defined CONFIG_MACH_SUN8I_H3
 	printf("CPU:   Allwinner H3 (SUN8I %04x)\n", sunxi_get_sram_id());
 #elif defined CONFIG_MACH_SUN8I_R40
-- 
2.12.2