ARM: tegra: add common LP1 suspend support

The LP1 suspending mode on Tegra means CPU rail off, devices and PLLs are
clock gated and SDRAM in self-refresh mode. That means the low level LP1
suspending and resuming code couldn't be run on DRAM and the CPU must
switch to the always on clock domain (a.k.a. CLK_M 12MHz oscillator). And
the system clock (SCLK) would be switched to CLK_S, a 32KHz oscillator.
The LP1 low level handling code need to be moved to IRAM area first. And
marking the LP1 mask for indicating the Tegra device is in LP1. The CPU
power timer needs to be re-calculated based on 32KHz that was originally
based on PCLK.

When resuming from LP1, the LP1 reset handler will resume PLLs and then
put DRAM to normal mode. Then jumping to the "tegra_resume" that will
restore full context before back to kernel. The "tegra_resume" handler
was expected to be found in PMC_SCRATCH41 register.

This is common LP1 procedures for Tegra, so we do these jobs mainly in
this patch:
* moving LP1 low level handling code to IRAM
* marking LP1 mask
* copying the physical address of "tegra_resume" to PMC_SCRATCH41
* re-calculate the CPU power timer based on 32KHz

Signed-off-by: Joseph Lo <josephl@nvidia.com>
[swarren, replaced IRAM_CODE macro with IO_ADDRESS(TEGRA_IRAM_CODE_AREA)]
Signed-off-by: Stephen Warren <swarren@nvidia.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/arch/arm/mach-tegra/pmc.c b/arch/arm/mach-tegra/pmc.c
index 03e640512e3..8acb881f7cf 100644
--- a/arch/arm/mach-tegra/pmc.c
+++ b/arch/arm/mach-tegra/pmc.c
@@ -196,6 +196,24 @@ enum tegra_suspend_mode tegra_pmc_get_suspend_mode(void)
 	return pmc_pm_data.suspend_mode;
 }
 
+void tegra_pmc_set_suspend_mode(enum tegra_suspend_mode mode)
+{
+	if (mode < TEGRA_SUSPEND_NONE || mode >= TEGRA_MAX_SUSPEND_MODE)
+		return;
+
+	pmc_pm_data.suspend_mode = mode;
+}
+
+void tegra_pmc_suspend(void)
+{
+	tegra_pmc_writel(virt_to_phys(tegra_resume), PMC_SCRATCH41);
+}
+
+void tegra_pmc_resume(void)
+{
+	tegra_pmc_writel(0x0, PMC_SCRATCH41);
+}
+
 void tegra_pmc_pm_set(enum tegra_suspend_mode mode)
 {
 	u32 reg, csr_reg;
@@ -219,6 +237,9 @@ void tegra_pmc_pm_set(enum tegra_suspend_mode mode)
 	}
 
 	switch (mode) {
+	case TEGRA_SUSPEND_LP1:
+		rate = 32768;
+		break;
 	case TEGRA_SUSPEND_LP2:
 		rate = clk_get_rate(tegra_pclk);
 		break;