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clk: tegra20: Implementing CPU low-power function for tegra_cpu_car_ops 

Implementing suspend, resume and rail_off_ready API for tegra_cpu_car_ops. These
functions were used for CPU powered-down state maintenance.

Signed-off-by: Joseph Lo <josephl@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
This commit is contained in:
Joseph Lo 2013-01-15 22:10:48 +00:00 committed by Stephen Warren
parent 5c1350bdfc
commit 4a2e32794e
1 changed files with 93 additions and 0 deletions
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93
drivers/clk/tegra/clk-tegra20.c
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@ -21,6 +21,7 @@
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/clk/tegra.h>
#include <linux/delay.h>
#include "clk.h"
@ -104,6 +105,13 @@
#define SUPER_SCLK_DIVIDER 0x2c
#define CLK_SYSTEM_RATE 0x30
#define CCLK_BURST_POLICY_SHIFT 28
#define CCLK_RUN_POLICY_SHIFT 4
#define CCLK_IDLE_POLICY_SHIFT 0
#define CCLK_IDLE_POLICY 1
#define CCLK_RUN_POLICY 2
#define CCLK_BURST_POLICY_PLLX 8
#define CLK_SOURCE_I2S1 0x100
#define CLK_SOURCE_I2S2 0x104
#define CLK_SOURCE_SPDIF_OUT 0x108
@ -169,6 +177,17 @@
#define CPU_CLOCK(cpu) (0x1 << (8 + cpu))
#define CPU_RESET(cpu) (0x1111ul << (cpu))
#ifdef CONFIG_PM_SLEEP
static struct cpu_clk_suspend_context {
u32 pllx_misc;
u32 pllx_base;
u32 cpu_burst;
u32 clk_csite_src;
u32 cclk_divider;
} tegra20_cpu_clk_sctx;
#endif
static int periph_clk_enb_refcnt[CLK_OUT_ENB_NUM * 32];
static void __iomem *clk_base;
@ -1136,12 +1155,86 @@ static void tegra20_disable_cpu_clock(u32 cpu)
clk_base + TEGRA_CLK_RST_CONTROLLER_CLK_CPU_CMPLX);
}
#ifdef CONFIG_PM_SLEEP
static bool tegra20_cpu_rail_off_ready(void)
{
unsigned int cpu_rst_status;
cpu_rst_status = readl(clk_base +
TEGRA_CLK_RST_CONTROLLER_RST_CPU_CMPLX_SET);
return !!(cpu_rst_status & 0x2);
}
static void tegra20_cpu_clock_suspend(void)
{
/* switch coresite to clk_m, save off original source */
tegra20_cpu_clk_sctx.clk_csite_src =
readl(clk_base + CLK_SOURCE_CSITE);
writel(3<<30, clk_base + CLK_SOURCE_CSITE);
tegra20_cpu_clk_sctx.cpu_burst =
readl(clk_base + CCLK_BURST_POLICY);
tegra20_cpu_clk_sctx.pllx_base =
readl(clk_base + PLLX_BASE);
tegra20_cpu_clk_sctx.pllx_misc =
readl(clk_base + PLLX_MISC);
tegra20_cpu_clk_sctx.cclk_divider =
readl(clk_base + SUPER_CCLK_DIVIDER);
}
static void tegra20_cpu_clock_resume(void)
{
unsigned int reg, policy;
/* Is CPU complex already running on PLLX? */
reg = readl(clk_base + CCLK_BURST_POLICY);
policy = (reg >> CCLK_BURST_POLICY_SHIFT) & 0xF;
if (policy == CCLK_IDLE_POLICY)
reg = (reg >> CCLK_IDLE_POLICY_SHIFT) & 0xF;
else if (policy == CCLK_RUN_POLICY)
reg = (reg >> CCLK_RUN_POLICY_SHIFT) & 0xF;
else
BUG();
if (reg != CCLK_BURST_POLICY_PLLX) {
/* restore PLLX settings if CPU is on different PLL */
writel(tegra20_cpu_clk_sctx.pllx_misc,
clk_base + PLLX_MISC);
writel(tegra20_cpu_clk_sctx.pllx_base,
clk_base + PLLX_BASE);
/* wait for PLL stabilization if PLLX was enabled */
if (tegra20_cpu_clk_sctx.pllx_base & (1 << 30))
udelay(300);
}
/*
* Restore original burst policy setting for calls resulting from CPU
* LP2 in idle or system suspend.
*/
writel(tegra20_cpu_clk_sctx.cclk_divider,
clk_base + SUPER_CCLK_DIVIDER);
writel(tegra20_cpu_clk_sctx.cpu_burst,
clk_base + CCLK_BURST_POLICY);
writel(tegra20_cpu_clk_sctx.clk_csite_src,
clk_base + CLK_SOURCE_CSITE);
}
#endif
static struct tegra_cpu_car_ops tegra20_cpu_car_ops = {
.wait_for_reset = tegra20_wait_cpu_in_reset,
.put_in_reset = tegra20_put_cpu_in_reset,
.out_of_reset = tegra20_cpu_out_of_reset,
.enable_clock = tegra20_enable_cpu_clock,
.disable_clock = tegra20_disable_cpu_clock,
#ifdef CONFIG_PM_SLEEP
.rail_off_ready = tegra20_cpu_rail_off_ready,
.suspend = tegra20_cpu_clock_suspend,
.resume = tegra20_cpu_clock_resume,
#endif
};
static __initdata struct tegra_clk_init_table init_table[] = {