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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>
109 lines
3.0 KiB
C
109 lines
3.0 KiB
C
/*
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* arch/arm/mach-tegra/flowctrl.c
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*
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* functions and macros to control the flowcontroller
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*
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* Copyright (c) 2010-2012, NVIDIA Corporation. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/io.h>
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#include <linux/cpumask.h>
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#include "flowctrl.h"
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#include "iomap.h"
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u8 flowctrl_offset_halt_cpu[] = {
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FLOW_CTRL_HALT_CPU0_EVENTS,
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FLOW_CTRL_HALT_CPU1_EVENTS,
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FLOW_CTRL_HALT_CPU1_EVENTS + 8,
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FLOW_CTRL_HALT_CPU1_EVENTS + 16,
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};
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u8 flowctrl_offset_cpu_csr[] = {
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FLOW_CTRL_CPU0_CSR,
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FLOW_CTRL_CPU1_CSR,
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FLOW_CTRL_CPU1_CSR + 8,
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FLOW_CTRL_CPU1_CSR + 16,
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};
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static void flowctrl_update(u8 offset, u32 value)
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{
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void __iomem *addr = IO_ADDRESS(TEGRA_FLOW_CTRL_BASE) + offset;
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writel(value, addr);
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/* ensure the update has reached the flow controller */
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wmb();
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readl_relaxed(addr);
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}
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u32 flowctrl_read_cpu_csr(unsigned int cpuid)
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{
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u8 offset = flowctrl_offset_cpu_csr[cpuid];
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void __iomem *addr = IO_ADDRESS(TEGRA_FLOW_CTRL_BASE) + offset;
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return readl(addr);
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}
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void flowctrl_write_cpu_csr(unsigned int cpuid, u32 value)
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{
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return flowctrl_update(flowctrl_offset_cpu_csr[cpuid], value);
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}
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void flowctrl_write_cpu_halt(unsigned int cpuid, u32 value)
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{
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return flowctrl_update(flowctrl_offset_halt_cpu[cpuid], value);
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}
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void flowctrl_cpu_suspend_enter(unsigned int cpuid)
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{
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unsigned int reg;
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int i;
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reg = flowctrl_read_cpu_csr(cpuid);
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reg &= ~TEGRA30_FLOW_CTRL_CSR_WFE_BITMAP; /* clear wfe bitmap */
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reg &= ~TEGRA30_FLOW_CTRL_CSR_WFI_BITMAP; /* clear wfi bitmap */
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reg |= FLOW_CTRL_CSR_INTR_FLAG; /* clear intr flag */
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reg |= FLOW_CTRL_CSR_EVENT_FLAG; /* clear event flag */
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reg |= TEGRA30_FLOW_CTRL_CSR_WFI_CPU0 << cpuid; /* pwr gating on wfi */
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reg |= FLOW_CTRL_CSR_ENABLE; /* pwr gating */
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flowctrl_write_cpu_csr(cpuid, reg);
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for (i = 0; i < num_possible_cpus(); i++) {
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if (i == cpuid)
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continue;
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reg = flowctrl_read_cpu_csr(i);
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reg |= FLOW_CTRL_CSR_EVENT_FLAG;
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reg |= FLOW_CTRL_CSR_INTR_FLAG;
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flowctrl_write_cpu_csr(i, reg);
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}
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}
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void flowctrl_cpu_suspend_exit(unsigned int cpuid)
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{
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unsigned int reg;
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/* Disable powergating via flow controller for CPU0 */
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reg = flowctrl_read_cpu_csr(cpuid);
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reg &= ~TEGRA30_FLOW_CTRL_CSR_WFE_BITMAP; /* clear wfe bitmap */
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reg &= ~TEGRA30_FLOW_CTRL_CSR_WFI_BITMAP; /* clear wfi bitmap */
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reg &= ~FLOW_CTRL_CSR_ENABLE; /* clear enable */
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reg |= FLOW_CTRL_CSR_INTR_FLAG; /* clear intr */
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reg |= FLOW_CTRL_CSR_EVENT_FLAG; /* clear event */
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flowctrl_write_cpu_csr(cpuid, reg);
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}
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