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94 lines
2.2 KiB
94 lines
2.2 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* leon_pmc.c: LEON Power-down cpu_idle() handler |
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* |
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* Copyright (C) 2011 Daniel Hellstrom ([email protected]) Aeroflex Gaisler AB |
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*/ |
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#include <linux/init.h> |
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#include <linux/pm.h> |
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#include <asm/leon_amba.h> |
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#include <asm/cpu_type.h> |
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#include <asm/leon.h> |
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#include <asm/processor.h> |
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/* List of Systems that need fixup instructions around power-down instruction */ |
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static unsigned int pmc_leon_fixup_ids[] = { |
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AEROFLEX_UT699, |
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GAISLER_GR712RC, |
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LEON4_NEXTREME1, |
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0 |
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}; |
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static int pmc_leon_need_fixup(void) |
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{ |
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unsigned int systemid = amba_system_id >> 16; |
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unsigned int *id; |
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id = &pmc_leon_fixup_ids[0]; |
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while (*id != 0) { |
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if (*id == systemid) |
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return 1; |
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id++; |
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} |
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return 0; |
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} |
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/* |
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* CPU idle callback function for systems that need some extra handling |
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* See .../arch/sparc/kernel/process.c |
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*/ |
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static void pmc_leon_idle_fixup(void) |
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{ |
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/* Prepare an address to a non-cachable region. APB is always |
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* none-cachable. One instruction is executed after the Sleep |
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* instruction, we make sure to read the bus and throw away the |
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* value by accessing a non-cachable area, also we make sure the |
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* MMU does not get a TLB miss here by using the MMU BYPASS ASI. |
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*/ |
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register unsigned int address = (unsigned int)leon3_irqctrl_regs; |
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/* Interrupts need to be enabled to not hang the CPU */ |
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raw_local_irq_enable(); |
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__asm__ __volatile__ ( |
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"wr %%g0, %%asr19\n" |
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"lda [%0] %1, %%g0\n" |
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: |
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: "r"(address), "i"(ASI_LEON_BYPASS)); |
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} |
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/* |
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* CPU idle callback function |
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* See .../arch/sparc/kernel/process.c |
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*/ |
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static void pmc_leon_idle(void) |
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{ |
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/* Interrupts need to be enabled to not hang the CPU */ |
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raw_local_irq_enable(); |
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/* For systems without power-down, this will be no-op */ |
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__asm__ __volatile__ ("wr %g0, %asr19\n\t"); |
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} |
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/* Install LEON Power Down function */ |
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static int __init leon_pmc_install(void) |
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{ |
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if (sparc_cpu_model == sparc_leon) { |
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/* Assign power management IDLE handler */ |
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if (pmc_leon_need_fixup()) |
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sparc_idle = pmc_leon_idle_fixup; |
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else |
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sparc_idle = pmc_leon_idle; |
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printk(KERN_INFO "leon: power management initialized\n"); |
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} |
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return 0; |
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} |
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/* This driver is not critical to the boot process, don't care |
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* if initialized late. |
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*/ |
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late_initcall(leon_pmc_install);
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