ARM: OMAP2+: PRCM: create SoC-specific chip restart functions

Split omap_prcm_restart() from mach-omap2/prcm.c into SoC-specific
variants.  These functions need to be able to save the reboot reason
into the scratchpad RAM.  This implies a dependency on both the PRM
and SCM IP blocks, so they've been moved into their own file.  This
will eventually call functions in the PRM and SCM drivers, once those
are created.

Vaibhav Hiremath <hvaibhav@ti.com> identified an unused prototype in
the first version of this patch - now removed.  Tony Lindgren
<tony@atomide.com> noted a compile problem with some RMK Kconfigs;
resolved in this patch.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Vaibhav Hiremath <hvaibhav@ti.com>
Tested-by: Vaibhav Hiremath <hvaibhav@ti.com>
Cc: Tony Lindgren <tony@atomide.com>

1 files changed, 65 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/omap2-restart.c b/arch/arm/mach-omap2/omap2-restart.c
new file mode 100644
index 00000000000..be6bc89ab1e
--- /dev/null
+++ b/arch/arm/mach-omap2/omap2-restart.c
@@ -0,0 +1,65 @@
+/*
+ * omap2-restart.c - code common to all OMAP2xxx machines.
+ *
+ * Copyright (C) 2012 Texas Instruments
+ * Paul Walmsley
+ *
+ * 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/init.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+
+#include "common.h"
+#include "prm2xxx.h"
+
+/*
+ * reset_virt_prcm_set_ck, reset_sys_ck: pointers to the virt_prcm_set
+ * clock and the sys_ck.  Used during the reset process
+ */
+static struct clk *reset_virt_prcm_set_ck, *reset_sys_ck;
+
+/* Reboot handling */
+
+/**
+ * omap2xxx_restart - Set DPLL to bypass mode for reboot to work
+ *
+ * Set the DPLL to bypass so that reboot completes successfully.  No
+ * return value.
+ */
+void omap2xxx_restart(char mode, const char *cmd)
+{
+	u32 rate;
+
+	rate = clk_get_rate(reset_sys_ck);
+	clk_set_rate(reset_virt_prcm_set_ck, rate);
+
+	/* XXX Should save the cmd argument for use after the reboot */
+
+	omap2xxx_prm_dpll_reset(); /* never returns */
+	while (1);
+}
+
+/**
+ * omap2xxx_common_look_up_clks_for_reset - look up clocks needed for restart
+ *
+ * Some clocks need to be looked up in advance for the SoC restart
+ * operation to work - see omap2xxx_restart().  Returns -EINVAL upon
+ * error or 0 upon success.
+ */
+static int __init omap2xxx_common_look_up_clks_for_reset(void)
+{
+	reset_virt_prcm_set_ck = clk_get(NULL, "virt_prcm_set");
+	if (IS_ERR(reset_virt_prcm_set_ck))
+		return -EINVAL;
+
+	reset_sys_ck = clk_get(NULL, "sys_ck");
+	if (IS_ERR(reset_sys_ck))
+		return -EINVAL;
+
+	return 0;
+}
+core_initcall(omap2xxx_common_look_up_clks_for_reset);