[PATCH 3/3] omap3: make coresight register save across OFF modes a sysfs option

Alexander Shishkin
2010-08-26T09:18:13Z

This adds a sysfs file at /sys/power/coresight_save which is used to
control if the ETM and debug components' states should be saved and
restored across OFF modes.

Signed-off-by: Alexander Shishkin <virtuoso@slind.org>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: linux-omap@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
---
arch/arm/mach-omap2/Makefile | 1 +
arch/arm/mach-omap2/debug34xx.c | 66 +++++++++++++++++++++++++++++++++++++++
arch/arm/mach-omap2/pm.h | 6 +++
arch/arm/mach-omap2/pm34xx.c | 3 ++
4 files changed, 76 insertions(+), 0 deletions(-)
create mode 100644 arch/arm/mach-omap2/debug34xx.c

diff --git a/arch/arm/mach-omap2/Makefile b/arch/arm/mach-omap2/Makefile
index 88d3a1e..0545dd8 100644
--- a/arch/arm/mach-omap2/Makefile
+++ b/arch/arm/mach-omap2/Makefile
@@ -52,6 +52,7 @@ obj-$(CONFIG_ARCH_OMAP2) += pm24xx.o
obj-$(CONFIG_ARCH_OMAP2) += sleep24xx.o
obj-$(CONFIG_ARCH_OMAP3) += pm34xx.o sleep34xx.o cpuidle34xx.o
obj-$(CONFIG_ARCH_OMAP4) += pm44xx.o
+obj-$(CONFIG_ENABLE_OFF_MODE_JTAG_ETM_DEBUG) += debug34xx.o
obj-$(CONFIG_PM_DEBUG) += pm-debug.o

AFLAGS_sleep24xx.o :=-Wa,-march=armv6
diff --git a/arch/arm/mach-omap2/debug34xx.c b/arch/arm/mach-omap2/debug34xx.c
new file mode 100644
index 0000000..698e83a
--- /dev/null
+++ b/arch/arm/mach-omap2/debug34xx.c
@@ -0,0 +1,66 @@
+/*
+ * Control saving and restoring of coresight components' state during
+ * OFF mode.
+ *
+ * Copyright (C) 2010 Nokia Corporation
+ * Alexander Shishkin
+ *
+ * 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/sysfs.h>
+#include <linux/kobject.h>
+
+#include "pm.h"
+
+/*
+ * Pointer to a place in sram where the ETM/debug state save
+ * flag is. It can be calculated after the omap_sram_idle is
+ * pushed to sram.
+ */
+static unsigned int *_etm_save;
+
+/*
+ * sysfs file /sys/power/coresight_save controls whether the
+ * state of coresight components should be saved and restored
+ * across OFF modes.
+ */
+static ssize_t coresight_save_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%u\n", *_etm_save);
+}
+
+static ssize_t coresight_save_store(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *buf, size_t n)
+{
+ unsigned int value;
+
+ if (sscanf(buf, "%u", &value) != 1)
+ return -EINVAL;
+
+ *_etm_save = !!value;
+
+ return n;
+}
+
+static struct kobj_attribute coresight_save_attr =
+ __ATTR(coresight_save, 0644, coresight_save_show, coresight_save_store);
+
+int omap3_coresight_pm_init(void *sram_addr)
+{
+ int ret;
+
+ /* the last word from the top of omap_sram_idle */
+ _etm_save = (unsigned *)((u8 *)sram_addr + omap34xx_cpu_suspend_sz - 4);
+
+ ret = sysfs_create_file(power_kobj, &coresight_save_attr.attr);
+
+ return ret;
+}
+
diff --git a/arch/arm/mach-omap2/pm.h b/arch/arm/mach-omap2/pm.h
index 3de6ece..0321834 100644
--- a/arch/arm/mach-omap2/pm.h
+++ b/arch/arm/mach-omap2/pm.h
@@ -76,6 +76,12 @@ extern void omap34xx_cpu_suspend(u32 *addr, int save_state);
extern void save_secure_ram_context(u32 *addr);
extern void omap3_save_scratchpad_contents(void);

+#ifdef CONFIG_ENABLE_OFF_MODE_JTAG_ETM_DEBUG
+int omap3_coresight_pm_init(void *sram_addr);
+#else
+#define omap3_coresight_pm_init(x) do {} while (0)
+#endif
+
extern unsigned int omap24xx_idle_loop_suspend_sz;
extern unsigned int omap34xx_suspend_sz;
extern unsigned int save_secure_ram_context_sz;
diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
index 7b03426..8f925db 100644
--- a/arch/arm/mach-omap2/pm34xx.c
+++ b/arch/arm/mach-omap2/pm34xx.c
@@ -1098,6 +1098,9 @@ static int __init omap3_pm_init(void)
core_clkdm = clkdm_lookup("core_clkdm");

omap_push_sram_idle();
+
+ omap3_coresight_pm_init(_omap_sram_idle);
+
#ifdef CONFIG_SUSPEND
suspend_set_ops(&omap_pm_ops);
#endif /* CONFIG_SUSPEND */
--
1.7.2.1.45.gb66c2