[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>
diff --git a/arch/arm/mach-pxa/reset.c b/arch/arm/mach-pxa/reset.c
new file mode 100644
index 0000000..551f313
--- /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;
+ }
+}
+