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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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d72ee6be58
This enables interrupts for Leon before having the CPU enter power-down mode.
Commit 87fa05aeb3, "sparc: Use generic idle loop",
gets the CPU stuck on idle for Leon systems. On Leon, disabling interrupts and
powering down the processor will get the processor stuck waiting for an
interrupt that will never be reacted to.
Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
94 lines
2.1 KiB
C
94 lines
2.1 KiB
C
/* leon_pmc.c: LEON Power-down cpu_idle() handler
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*
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* Copyright (C) 2011 Daniel Hellstrom (daniel@gaisler.com) 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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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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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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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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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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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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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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