Thanks for your feedback Rob.
On 8/10/2012 3:10 PM, Rob Herring wrote:
On 08/10/2012 04:58 PM, Rohit Vaswani wrote:
The current arch_timer only support accessing through CP15 interface.
Add support for ARM processors that only support IO mapped register
interface
Signed-off-by: Rohit Vaswani <rvaswani@xxxxxxxxxxxxxx>
---
.../devicetree/bindings/arm/arch_timer.txt | 7 +
arch/arm/kernel/arch_timer.c | 259 ++++++++++++++++----
2 files changed, 223 insertions(+), 43 deletions(-)
The original file is 360 lines. It doesn't really seem like there's a
lot of overlap and I wonder if it is worth the extra overhead.
diff --git a/Documentation/devicetree/bindings/arm/arch_timer.txt b/Documentation/devicetree/bindings/arm/arch_timer.txt
index 52478c8..1c71799 100644
--- a/Documentation/devicetree/bindings/arm/arch_timer.txt
+++ b/Documentation/devicetree/bindings/arm/arch_timer.txt
@@ -14,6 +14,13 @@ The timer is attached to a GIC to deliver its per-processor interrupts.
- clock-frequency : The frequency of the main counter, in Hz. Optional.
+- irq-is-not-percpu: Specify is the timer irq is *NOT* a percpu (PPI) interrupt
+ In the default case i.e without this property, the timer irq is treated as a
+ PPI interrupt. Optional.
The first field in the gic interrupts binding already defines this.
Is there a generic way to extract that information from the interrupts
binding. I saw Chris Smith's patch that adds irq_is_per_cpu function.
Perhaps we can use that once it is merged ?
+
+- If the node address and reg is specified, the arch_timer will try to use the memory
+ mapped timer. Optional.
This timer is fundamentally different h/w. You need a new compatible string.
I think that the timer is the same, but it just has a different
interface. Do you still think we need a new compatible string ?
+
Example:
timer {
diff --git a/arch/arm/kernel/arch_timer.c b/arch/arm/kernel/arch_timer.c
index 1d0d9df..09604b7 100644
--- a/arch/arm/kernel/arch_timer.c
+++ b/arch/arm/kernel/arch_timer.c
@@ -18,6 +18,7 @@
#include <linux/clockchips.h>
#include <linux/interrupt.h>
#include <linux/of_irq.h>
+#include <linux/of_address.h>
#include <linux/io.h>
#include <asm/cputype.h>
@@ -29,8 +30,17 @@
static unsigned long arch_timer_rate;
static int arch_timer_ppi;
static int arch_timer_ppi2;
+static int is_irq_percpu;
static struct clock_event_device __percpu **arch_timer_evt;
+static void __iomem *timer_base;
+
+struct arch_timer_operations {
+ void (*reg_write)(int, u32);
+ u32 (*reg_read)(int);
+ cycle_t (*get_cntpct)(void);
+ cycle_t (*get_cntvct)(void);
+};
/*
* Architected system timer support.
@@ -44,7 +54,29 @@ static struct clock_event_device __percpu **arch_timer_evt;
#define ARCH_TIMER_REG_FREQ 1
#define ARCH_TIMER_REG_TVAL 2
-static void arch_timer_reg_write(int reg, u32 val)
+/* Iomapped Register Offsets */
+#define ARCH_TIMER_CNTP_LOW_REG 0x000
+#define ARCH_TIMER_CNTP_HIGH_REG 0x004
+#define ARCH_TIMER_CNTV_LOW_REG 0x008
+#define ARCH_TIMER_CNTV_HIGH_REG 0x00C
+#define ARCH_TIMER_CTRL_REG 0x02C
+#define ARCH_TIMER_FREQ_REG 0x010
+#define ARCH_TIMER_CNTP_TVAL_REG 0x028
+#define ARCH_TIMER_CNTV_TVAL_REG 0x038
+
+static void timer_reg_write_mem(int reg, u32 val)
+{
+ switch (reg) {
+ case ARCH_TIMER_REG_CTRL:
+ __raw_writel(val, timer_base + ARCH_TIMER_CTRL_REG);
+ break;
+ case ARCH_TIMER_REG_TVAL:
+ __raw_writel(val, timer_base + ARCH_TIMER_CNTP_TVAL_REG);
+ break;
This whole function seems a bit pointless as it only adds timer_base.
Rob
I tried to the keep the functions similar to the cp15 interface ones. Is
there something else you suggest doing ?
Thanks,
Rohit Vaswani
--
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
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