kernel-ark/arch/arm/mach-tegra/flowctrl.c
Joseph Lo afec581c4b ARM: tegra20: flowctrl: add support for cpu_suspend_enter/exit
The flow controller can help CPU to go into suspend mode (powered-down
state). When CPU go into powered-down state, it needs some careful
settings before getting into and after leaving. The enter and exit
functions do that by configuring appropriate mode for flow controller.

Signed-off-by: Joseph Lo <josephl@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
2013-01-28 11:20:38 -07:00

137 lines
3.6 KiB
C

/*
* arch/arm/mach-tegra/flowctrl.c
*
* functions and macros to control the flowcontroller
*
* Copyright (c) 2010-2012, 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 that 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/init.h>
#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/cpumask.h>
#include "flowctrl.h"
#include "iomap.h"
#include "fuse.h"
static u8 flowctrl_offset_halt_cpu[] = {
FLOW_CTRL_HALT_CPU0_EVENTS,
FLOW_CTRL_HALT_CPU1_EVENTS,
FLOW_CTRL_HALT_CPU1_EVENTS + 8,
FLOW_CTRL_HALT_CPU1_EVENTS + 16,
};
static u8 flowctrl_offset_cpu_csr[] = {
FLOW_CTRL_CPU0_CSR,
FLOW_CTRL_CPU1_CSR,
FLOW_CTRL_CPU1_CSR + 8,
FLOW_CTRL_CPU1_CSR + 16,
};
static void flowctrl_update(u8 offset, u32 value)
{
void __iomem *addr = IO_ADDRESS(TEGRA_FLOW_CTRL_BASE) + offset;
writel(value, addr);
/* ensure the update has reached the flow controller */
wmb();
readl_relaxed(addr);
}
u32 flowctrl_read_cpu_csr(unsigned int cpuid)
{
u8 offset = flowctrl_offset_cpu_csr[cpuid];
void __iomem *addr = IO_ADDRESS(TEGRA_FLOW_CTRL_BASE) + offset;
return readl(addr);
}
void flowctrl_write_cpu_csr(unsigned int cpuid, u32 value)
{
return flowctrl_update(flowctrl_offset_cpu_csr[cpuid], value);
}
void flowctrl_write_cpu_halt(unsigned int cpuid, u32 value)
{
return flowctrl_update(flowctrl_offset_halt_cpu[cpuid], value);
}
void flowctrl_cpu_suspend_enter(unsigned int cpuid)
{
unsigned int reg;
int i;
reg = flowctrl_read_cpu_csr(cpuid);
switch (tegra_chip_id) {
case TEGRA20:
/* clear wfe bitmap */
reg &= ~TEGRA20_FLOW_CTRL_CSR_WFE_BITMAP;
/* clear wfi bitmap */
reg &= ~TEGRA20_FLOW_CTRL_CSR_WFI_BITMAP;
/* pwr gating on wfe */
reg |= TEGRA20_FLOW_CTRL_CSR_WFE_CPU0 << cpuid;
break;
case TEGRA30:
/* clear wfe bitmap */
reg &= ~TEGRA30_FLOW_CTRL_CSR_WFE_BITMAP;
/* clear wfi bitmap */
reg &= ~TEGRA30_FLOW_CTRL_CSR_WFI_BITMAP;
/* pwr gating on wfi */
reg |= TEGRA30_FLOW_CTRL_CSR_WFI_CPU0 << cpuid;
break;
}
reg |= FLOW_CTRL_CSR_INTR_FLAG; /* clear intr flag */
reg |= FLOW_CTRL_CSR_EVENT_FLAG; /* clear event flag */
reg |= FLOW_CTRL_CSR_ENABLE; /* pwr gating */
flowctrl_write_cpu_csr(cpuid, reg);
for (i = 0; i < num_possible_cpus(); i++) {
if (i == cpuid)
continue;
reg = flowctrl_read_cpu_csr(i);
reg |= FLOW_CTRL_CSR_EVENT_FLAG;
reg |= FLOW_CTRL_CSR_INTR_FLAG;
flowctrl_write_cpu_csr(i, reg);
}
}
void flowctrl_cpu_suspend_exit(unsigned int cpuid)
{
unsigned int reg;
/* Disable powergating via flow controller for CPU0 */
reg = flowctrl_read_cpu_csr(cpuid);
switch (tegra_chip_id) {
case TEGRA20:
/* clear wfe bitmap */
reg &= ~TEGRA20_FLOW_CTRL_CSR_WFE_BITMAP;
/* clear wfi bitmap */
reg &= ~TEGRA20_FLOW_CTRL_CSR_WFI_BITMAP;
break;
case TEGRA30:
/* clear wfe bitmap */
reg &= ~TEGRA30_FLOW_CTRL_CSR_WFE_BITMAP;
/* clear wfi bitmap */
reg &= ~TEGRA30_FLOW_CTRL_CSR_WFI_BITMAP;
break;
}
reg &= ~FLOW_CTRL_CSR_ENABLE; /* clear enable */
reg |= FLOW_CTRL_CSR_INTR_FLAG; /* clear intr */
reg |= FLOW_CTRL_CSR_EVENT_FLAG; /* clear event */
flowctrl_write_cpu_csr(cpuid, reg);
}