ARM: tegra: add LP1 suspend support for Tegra30

The LP1 suspend mode will power off the CPU, clock gated the PLLs and put
SDRAM to self-refresh mode. Any interrupt can wake up device from LP1. The
sequence when LP1 suspending:

* tunning off L1 data cache and the MMU
* storing some EMC registers, DPD (deep power down) status, clk source of
  mselect and SCLK burst policy
* putting SDRAM into self-refresh
* switching CPU to CLK_M (12MHz OSC)
* tunning off PLLM, PLLP, PLLA, PLLC and PLLX
* switching SCLK to CLK_S (32KHz OSC)
* shutting off the CPU rail

The sequence of LP1 resuming:

* re-enabling PLLM, PLLP, PLLA, PLLC and PLLX
* restoring the clk source of mselect and SCLK burst policy
* setting up CCLK burst policy to PLLX
* restoring DPD status and some EMC registers
* resuming SDRAM to normal mode
* jumping to the "tegra_resume" from PMC_SCRATCH41

Due to the SDRAM will be put into self-refresh mode, the low level
procedures of LP1 suspending and resuming should be copied to
TEGRA_IRAM_CODE_AREA (TEGRA_IRAM_BASE + SZ_4K) when suspending. Before
restoring the CPU context when resuming, the SDRAM needs to be switched
back to normal mode. And the PLLs need to be re-enabled, SCLK burst policy
be restored, CCLK burst policy be set in PLLX. Then jumping to
"tegra_resume" that was expected to be stored in PMC_SCRATCH41 to restore
CPU context and back to kernel.

Based on the work by: Scott Williams <scwilliams@nvidia.com>
Signed-off-by: Joseph Lo <josephl@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>

arch/arm/mach-tegra/Makefile

@@ -22,6 +22,7 @@ obj-$(CONFIG_ARCH_TEGRA_2x_SOC)		+= cpuidle-tegra20.o
 endif
 obj-$(CONFIG_ARCH_TEGRA_3x_SOC)		+= tegra30_speedo.o
 obj-$(CONFIG_ARCH_TEGRA_3x_SOC)		+= sleep-tegra30.o
+obj-$(CONFIG_ARCH_TEGRA_3x_SOC)		+= pm-tegra30.o
 ifeq ($(CONFIG_CPU_IDLE),y)
 obj-$(CONFIG_ARCH_TEGRA_3x_SOC)		+= cpuidle-tegra30.o
 endif

arch/arm/mach-tegra/pm-tegra30.c

+/*
+ * Copyright (c) 2013, NVIDIA Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <linux/kernel.h>
+
+#include "pm.h"
+
+#ifdef CONFIG_PM_SLEEP
+extern u32 tegra30_iram_start, tegra30_iram_end;
+extern void tegra30_sleep_core_finish(unsigned long);
+
+void tegra30_lp1_iram_hook(void)
+{
+	tegra_lp1_iram.start_addr = &tegra30_iram_start;
+	tegra_lp1_iram.end_addr = &tegra30_iram_end;
+}
+
+void tegra30_sleep_core_init(void)
+{
+	tegra_sleep_core_finish = tegra30_sleep_core_finish;
+}
+#endif

arch/arm/mach-tegra/pm.c

@@ -209,6 +209,15 @@ static int tegra_sleep_core(unsigned long v2p)
  */
 static bool tegra_lp1_iram_hook(void)
 {
+	switch (tegra_chip_id) {
+	case TEGRA30:
+		if (IS_ENABLED(CONFIG_ARCH_TEGRA_3x_SOC))
+			tegra30_lp1_iram_hook();
+		break;
+	default:
+		break;
+	}
+
 	if (!tegra_lp1_iram.start_addr || !tegra_lp1_iram.end_addr)
 		return false;
 
@@ -222,6 +231,15 @@ static bool tegra_lp1_iram_hook(void)
 
 static bool tegra_sleep_core_init(void)
 {
+	switch (tegra_chip_id) {
+	case TEGRA30:
+		if (IS_ENABLED(CONFIG_ARCH_TEGRA_3x_SOC))
+			tegra30_sleep_core_init();
+		break;
+	default:
+		break;
+	}
+
 	if (!tegra_sleep_core_finish)
 		return false;
 

arch/arm/mach-tegra/pm.h

@@ -30,6 +30,9 @@ struct tegra_lp1_iram {
 extern struct tegra_lp1_iram tegra_lp1_iram;
 extern void (*tegra_sleep_core_finish)(unsigned long v2p);
 
+void tegra30_lp1_iram_hook(void);
+void tegra30_sleep_core_init(void);
+
 extern unsigned long l2x0_saved_regs_addr;
 
 void save_cpu_arch_register(void);

arch/arm/mach-tegra/sleep.S

@@ -134,10 +134,10 @@ ENTRY(tegra_shut_off_mmu)
 #ifdef CONFIG_CACHE_L2X0
 	/* Disable L2 cache */
 	check_cpu_part_num 0xc09, r9, r10
-	movweq	r4, #:lower16:(TEGRA_ARM_PERIF_BASE + 0x3000)
-	movteq	r4, #:upper16:(TEGRA_ARM_PERIF_BASE + 0x3000)
-	moveq	r5, #0
-	streq	r5, [r4, #L2X0_CTRL]
+	movweq	r2, #:lower16:(TEGRA_ARM_PERIF_BASE + 0x3000)
+	movteq	r2, #:upper16:(TEGRA_ARM_PERIF_BASE + 0x3000)
+	moveq	r3, #0
+	streq	r3, [r2, #L2X0_CTRL]
 #endif
 	mov	pc, r0
 ENDPROC(tegra_shut_off_mmu)

arch/arm/mach-tegra/sleep.h

@@ -46,6 +46,14 @@
 #define TEGRA_FLUSH_CACHE_ALL	1
 
 #ifdef __ASSEMBLY__
+/* waits until the microsecond counter (base) is > rn */
+.macro wait_until, rn, base, tmp
+	add	\rn, \rn, #1
+1001:	ldr	\tmp, [\base]
+	cmp	\tmp, \rn
+	bmi	1001b
+.endm
+
 /* returns the offset of the flow controller halt register for a cpu */
 .macro cpu_to_halt_reg rd, rcpu
 	cmp	\rcpu, #0