[PATCH v5 1/7] ARM: S5PV210: Allow to probe EVT revision number.

[MyungJoo Ham]

Early products of S5PV210, EVT0, had several errata that require
kernel to avoid using some parts/instructions of the CPU or to
add protection instructions. There are products with such early
production CPUs; thus, we want to distinguish them in kernel.
This patch is to distinguish such products.

Include <mach/hardware.h> and call s5pv210_revision().

For example,

	if (s5pv210_revision(EVT0)) {
		... execute code targeted only to EVT0 ...
	} else {
		... execute normal code ...
	}

Call set_s5pv210_revision(EVTx) when the EVT revision number can be
identified. We have EVT0, EVT1, and EVT1-Fused avaialble right now and
only EVT1-Fused has the unique revision number at chipid (PRO_ID
register). A function, get_s5pv210_revision_chipid(), returns EVT
revision number if the revision is identified by the chipid; otherwise,
the function returns EVT_UNKNOWN. When EVT cannot be identified with
chipid, it can be identified at board support file
(arch/arm/mach-s5pv210/mach-*.c), not at the cpu file
(arch/arm/mach-s5pv210/cpu.c).

For Aquila machine. (mach-aquila.c)

Part of Aquila machines have the early production CPUs that require
to address errata issues. Note that we don't do this for GONI machines
because they have never used early production CPUs with errata. Besides,
please note that there are other boards that use such early produces
other than Aquila. However, those boards/machines are not registered at
the /linux/arch/arm/tools/mach-types, yet; thus, we have omitted them
in this patch.

For Goni machine. (mach-goni.c)

It's either EVT1 or EVT1-Fused; thus, it can be identified by
get_s5pv210_revision_chipid() function.

Signed-off-by: MyungJoo Ham <myungjoo.ham at samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park at samsung.com>
--
v5:
	- rename revision check function.
	- revise revision check functions so that it does not access
	  board-related information.
	- chipid is used to identify EVT revision.
	- added "s5pv210_revision_or_later()" function
---
 arch/arm/mach-s5pv210/cpu.c                   |   29 +++++++++++++++++++++++++
 arch/arm/mach-s5pv210/include/mach/hardware.h |   19 +++++++++++++++-
 arch/arm/mach-s5pv210/mach-aquila.c           |   14 ++++++++++++
 arch/arm/mach-s5pv210/mach-goni.c             |    8 +++++++
 4 files changed, 69 insertions(+), 1 deletions(-)

diff --git a/arch/arm/mach-s5pv210/cpu.c b/arch/arm/mach-s5pv210/cpu.c
index 94c632b..77bf37d 100644
--- a/arch/arm/mach-s5pv210/cpu.c
+++ b/arch/arm/mach-s5pv210/cpu.c
@@ -24,9 +24,11 @@
 #include <asm/mach/map.h>
 #include <asm/mach/irq.h>
 
+#include <asm/mach-types.h>
 #include <asm/proc-fns.h>
 #include <mach/map.h>
 #include <mach/regs-clock.h>
+#include <mach/hardware.h>
 
 #include <plat/cpu.h>
 #include <plat/devs.h>
@@ -128,6 +130,33 @@ static struct sys_device s5pv210_sysdev = {
 	.cls	= &s5pv210_sysclass,
 };
 
+static enum s5pv210_revision s5pv210_evt_number = EVT_UNKNOWN;
+
+bool s5pv210_revision(enum s5pv210_revision rev)
+{
+	return rev == s5pv210_evt_number;
+}
+
+bool s5pv210_revision_or_later(enum s5pv210_revision rev)
+{
+	return rev >= s5pv210_evt_number;
+}
+
+void set_s5pv210_revision(enum s5pv210_revision rev)
+{
+	s5pv210_evt_number = rev;
+}
+
+enum s5pv210_revision get_s5pv210_revision_chipid(void)
+{
+	unsigned int reg = __raw_readl(S5P_VA_CHIPID);
+
+	if ((reg & 0xf0) == 0x20)
+		return EVT1_FUSED;
+
+	return EVT_UNKNOWN;
+}
+
 static int __init s5pv210_core_init(void)
 {
 	return sysdev_class_register(&s5pv210_sysclass);
diff --git a/arch/arm/mach-s5pv210/include/mach/hardware.h b/arch/arm/mach-s5pv210/include/mach/hardware.h
index fada7a3..c1702d6 100644
--- a/arch/arm/mach-s5pv210/include/mach/hardware.h
+++ b/arch/arm/mach-s5pv210/include/mach/hardware.h
@@ -13,6 +13,23 @@
 #ifndef __ASM_ARCH_HARDWARE_H
 #define __ASM_ARCH_HARDWARE_H __FILE__
 
-/* currently nothing here, placeholder */
+enum s5pv210_revision { EVT_UNKNOWN = 0,
+	EVT0,
+	EVT1,
+	EVT1_FUSED };
+
+extern bool s5pv210_revision(enum s5pv210_revision);
+extern bool s5pv210_revision_or_later(enum s5pv210_revision);
+extern void set_s5pv210_revision(enum s5pv210_revision);
+
+/*
+ * get_s5pv210_revision_chipid returns s5pv210_revision if the
+ * EVT revision can be determined by the chipid(PRO_ID) register.
+ * However, note that only EVT1-FUSED can be identified from it and
+ * it cannot distinguish between EVT0 and EVT1. In such case, it
+ * returns EVT_UNKNOWN. In such case use set_s5pv210_revision() to
+ * set the revision number manually.
+ */
+extern enum s5pv210_revision get_s5pv210_revision_chipid(void);
 
 #endif /* __ASM_ARCH_HARDWARE_H */
diff --git a/arch/arm/mach-s5pv210/mach-aquila.c b/arch/arm/mach-s5pv210/mach-aquila.c
index 46d5c7e..25f45d1 100644
--- a/arch/arm/mach-s5pv210/mach-aquila.c
+++ b/arch/arm/mach-s5pv210/mach-aquila.c
@@ -30,6 +30,7 @@
 #include <mach/regs-clock.h>
 #include <mach/regs-fb.h>
 #include <mach/gpio.h>
+#include <mach/hardware.h>
 
 #include <plat/gpio-cfg.h>
 #include <plat/regs-serial.h>
@@ -536,6 +537,19 @@ static void __init aquila_map_io(void)
 
 static void __init aquila_machine_init(void)
 {
+	enum s5pv210_revision cpurev = get_s5pv210_revision_chipid();
+
+	/* CPU Revision (EVTx) */
+	if (cpurev == EVT_UNKNOWN) {
+		cpurev = EVT1;
+		if (system_rev & 0x0800) {
+			if ((system_rev & 0xF) < 8)
+				cpurev = EVT0;
+		} else if (system_rev & 0x2000)
+			cpurev = EVT0;
+	}
+	set_s5pv210_revision(cpurev);
+
 	/* PMIC */
 	aquila_pmic_init();
 	i2c_register_board_info(AP_I2C_GPIO_PMIC_BUS_4, i2c_gpio_pmic_devs,
diff --git a/arch/arm/mach-s5pv210/mach-goni.c b/arch/arm/mach-s5pv210/mach-goni.c
index 380d2ae..25a26ed 100644
--- a/arch/arm/mach-s5pv210/mach-goni.c
+++ b/arch/arm/mach-s5pv210/mach-goni.c
@@ -32,6 +32,7 @@
 #include <mach/regs-clock.h>
 #include <mach/regs-fb.h>
 #include <mach/gpio.h>
+#include <mach/hardware.h>
 
 #include <plat/gpio-cfg.h>
 #include <plat/regs-serial.h>
@@ -520,6 +521,13 @@ static void __init goni_map_io(void)
 
 static void __init goni_machine_init(void)
 {
+	enum s5pv210_revision cpurev = get_s5pv210_revision_chipid();
+
+	/* CPU Revision (EVTx) */
+	if (cpurev == EVT_UNKNOWN)
+		cpurev = EVT1;
+	set_s5pv210_revision(cpurev);
+
 	/* PMIC */
 	goni_pmic_init();
 	i2c_register_board_info(AP_I2C_GPIO_PMIC_BUS_4, i2c_gpio_pmic_devs,
-- 
1.6.3.3