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authorRussell King <rmk+kernel@arm.linux.org.uk>2010-01-16 18:07:08 +0300
committerRussell King <rmk+kernel@arm.linux.org.uk>2010-04-29 21:04:15 +0400
commitba02a21544b41a65e58506f1d79353203d94b8b6 (patch)
tree7dcd84b616003e7a3fb56fc23cc18dee0211b953
parenta285edcf18b8838814d645c7e411a337a825236e (diff)
downloadlinux-ba02a21544b41a65e58506f1d79353203d94b8b6.tar.xz
ARM: Improve documentation in arm_timer.h
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
-rw-r--r--arch/arm/include/asm/hardware/arm_timer.h39
1 files changed, 24 insertions, 15 deletions
diff --git a/arch/arm/include/asm/hardware/arm_timer.h b/arch/arm/include/asm/hardware/arm_timer.h
index 04be3bdf46b8..c0f4e7bf22de 100644
--- a/arch/arm/include/asm/hardware/arm_timer.h
+++ b/arch/arm/include/asm/hardware/arm_timer.h
@@ -1,21 +1,30 @@
#ifndef __ASM_ARM_HARDWARE_ARM_TIMER_H
#define __ASM_ARM_HARDWARE_ARM_TIMER_H
-#define TIMER_LOAD 0x00
-#define TIMER_VALUE 0x04
-#define TIMER_CTRL 0x08
-#define TIMER_CTRL_ONESHOT (1 << 0)
-#define TIMER_CTRL_32BIT (1 << 1)
-#define TIMER_CTRL_DIV1 (0 << 2)
-#define TIMER_CTRL_DIV16 (1 << 2)
-#define TIMER_CTRL_DIV256 (2 << 2)
-#define TIMER_CTRL_IE (1 << 5) /* Interrupt Enable (versatile only) */
-#define TIMER_CTRL_PERIODIC (1 << 6)
-#define TIMER_CTRL_ENABLE (1 << 7)
+/*
+ * ARM timer implementation, found in Integrator, Versatile and Realview
+ * platforms. Not all platforms support all registers and bits in these
+ * registers, so we mark them with A for Integrator AP, C for Integrator
+ * CP, V for Versatile and R for Realview.
+ *
+ * Integrator AP has 16-bit timers, Integrator CP, Versatile and Realview
+ * can have 16-bit or 32-bit selectable via a bit in the control register.
+ */
+#define TIMER_LOAD 0x00 /* ACVR rw */
+#define TIMER_VALUE 0x04 /* ACVR ro */
+#define TIMER_CTRL 0x08 /* ACVR rw */
+#define TIMER_CTRL_ONESHOT (1 << 0) /* CVR */
+#define TIMER_CTRL_32BIT (1 << 1) /* CVR */
+#define TIMER_CTRL_DIV1 (0 << 2) /* ACVR */
+#define TIMER_CTRL_DIV16 (1 << 2) /* ACVR */
+#define TIMER_CTRL_DIV256 (2 << 2) /* ACVR */
+#define TIMER_CTRL_IE (1 << 5) /* VR */
+#define TIMER_CTRL_PERIODIC (1 << 6) /* ACVR */
+#define TIMER_CTRL_ENABLE (1 << 7) /* ACVR */
-#define TIMER_INTCLR 0x0c
-#define TIMER_RIS 0x10
-#define TIMER_MIS 0x14
-#define TIMER_BGLOAD 0x18
+#define TIMER_INTCLR 0x0c /* ACVR wo */
+#define TIMER_RIS 0x10 /* CVR ro */
+#define TIMER_MIS 0x14 /* CVR ro */
+#define TIMER_BGLOAD 0x18 /* CVR rw */
#endif