From 75f10b465af9efd59906e9079ed9cbda7e0f7a43 Mon Sep 17 00:00:00 2001
From: Dmitry Baryshkov <dbaryshkov@gmail.com>
Date: Thu, 22 May 2008 16:20:18 +0100
Subject: [PATCH] [ARM] 5047/2: Support resetting by asserting GPIO pin
This adds support for resetting via assertion of GPIO pin.
This e.g. is used on Sharp Zaurus SL-6000.
Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>
Acked-by: Eric Miao <eric.miao@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
arch/arm/mach-pxa/Makefile | 2 +-
arch/arm/mach-pxa/reset.c | 95 +++++++++++++++++++++++++++++
include/asm-arm/arch-pxa/hardware.h | 5 ++
include/asm-arm/arch-pxa/system.h | 17 +-----
4 files changed, 102 insertions(+), 17 deletions(-)
create mode 100644 arch/arm/mach-pxa/reset.c
diff --git a/arch/arm/mach-pxa/Makefile b/arch/arm/mach-pxa/Makefile
index 0e6d05bb81aa9..c9e66fbe622e5 100644
--- a/arch/arm/mach-pxa/Makefile
+++ b/arch/arm/mach-pxa/Makefile
@@ -4,7 +4,7 @@
# Common support (must be linked before board specific support)
obj-y += clock.o devices.o generic.o irq.o dma.o \
- time.o gpio.o
+ time.o gpio.o reset.o
obj-$(CONFIG_PM) += pm.o sleep.o standby.o
obj-$(CONFIG_CPU_FREQ) += cpu-pxa.o
diff --git a/arch/arm/mach-pxa/reset.c b/arch/arm/mach-pxa/reset.c
new file mode 100644
index 0000000000000..551f313c94df2
--- /dev/null
+++ b/arch/arm/mach-pxa/reset.c
@@ -0,0 +1,95 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/gpio.h>
+#include <asm/io.h>
+#include <asm/proc-fns.h>
+
+#include <asm/arch/pxa-regs.h>
+
+static void do_hw_reset(void);
+
+static int reset_gpio = -1;
+
+int init_gpio_reset(int gpio)
+{
+ int rc;
+
+ rc = gpio_request(gpio, "reset generator");
+ if (rc) {
+ printk(KERN_ERR "Can't request reset_gpio\n");
+ goto out;
+ }
+
+ rc = gpio_direction_input(gpio);
+ if (rc) {
+ printk(KERN_ERR "Can't configure reset_gpio for input\n");
+ gpio_free(gpio);
+ goto out;
+ }
+
+out:
+ if (!rc)
+ reset_gpio = gpio;
+
+ return rc;
+}
+
+/*
+ * Trigger GPIO reset.
+ * This covers various types of logic connecting gpio pin
+ * to RESET pins (nRESET or GPIO_RESET):
+ */
+static void do_gpio_reset(void)
+{
+ BUG_ON(reset_gpio == -1);
+
+ /* drive it low */
+ gpio_direction_output(reset_gpio, 0);
+ mdelay(2);
+ /* rising edge or drive high */
+ gpio_set_value(reset_gpio, 1);
+ mdelay(2);
+ /* falling edge */
+ gpio_set_value(reset_gpio, 0);
+
+ /* give it some time */
+ mdelay(10);
+
+ WARN_ON(1);
+ /* fallback */
+ do_hw_reset();
+}
+
+static void do_hw_reset(void)
+{
+ /* Initialize the watchdog and let it fire */
+ OWER = OWER_WME;
+ OSSR = OSSR_M3;
+ OSMR3 = OSCR + 368640; /* ... in 100 ms */
+}
+
+void arch_reset(char mode)
+{
+ if (cpu_is_pxa2xx())
+ RCSR = RCSR_HWR | RCSR_WDR | RCSR_SMR | RCSR_GPR;
+
+ switch (mode) {
+ case 's':
+ /* Jump into ROM at address 0 */
+ cpu_reset(0);
+ break;
+ case 'h':
+ do_hw_reset();
+ break;
+ case 'g':
+ do_gpio_reset();
+ break;
+ }
+}
+
diff --git a/include/asm-arm/arch-pxa/hardware.h b/include/asm-arm/arch-pxa/hardware.h
index e25558faa5a48..5547ec797ad02 100644
--- a/include/asm-arm/arch-pxa/hardware.h
+++ b/include/asm-arm/arch-pxa/hardware.h
@@ -205,6 +205,11 @@ static inline void __deprecated pxa_set_cken(int clock, int enable)
*/
extern unsigned int get_memclk_frequency_10khz(void);
+/*
+ * register GPIO as reset generator
+ */
+extern int init_gpio_reset(int gpio);
+
#endif
#if defined(CONFIG_MACH_ARMCORE) && defined(CONFIG_PCI)
diff --git a/include/asm-arm/arch-pxa/system.h b/include/asm-arm/arch-pxa/system.h
index 9aa6c2e939e87..14894ae3fa676 100644
--- a/include/asm-arm/arch-pxa/system.h
+++ b/include/asm-arm/arch-pxa/system.h
@@ -20,19 +20,4 @@ static inline void arch_idle(void)
}
-static inline void arch_reset(char mode)
-{
- if (cpu_is_pxa2xx())
- RCSR = RCSR_HWR | RCSR_WDR | RCSR_SMR | RCSR_GPR;
-
- if (mode == 's') {
- /* Jump into ROM at address 0 */
- cpu_reset(0);
- } else {
- /* Initialize the watchdog and let it fire */
- OWER = OWER_WME;
- OSSR = OSSR_M3;
- OSMR3 = OSCR + 368640; /* ... in 100 ms */
- }
-}
-
+void arch_reset(char mode);
--
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