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86 lines
1.9 KiB
86 lines
1.9 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* arch/arm/kernel/crunch.c |
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* Cirrus MaverickCrunch context switching and handling |
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* |
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* Copyright (C) 2006 Lennert Buytenhek <[email protected]> |
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*/ |
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#include <linux/module.h> |
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#include <linux/types.h> |
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#include <linux/kernel.h> |
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#include <linux/signal.h> |
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#include <linux/sched.h> |
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#include <linux/init.h> |
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#include <linux/io.h> |
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#include <asm/thread_notify.h> |
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#include "soc.h" |
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struct crunch_state *crunch_owner; |
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void crunch_task_release(struct thread_info *thread) |
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{ |
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local_irq_disable(); |
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if (crunch_owner == &thread->crunchstate) |
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crunch_owner = NULL; |
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local_irq_enable(); |
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} |
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static int crunch_enabled(u32 devcfg) |
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{ |
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return !!(devcfg & EP93XX_SYSCON_DEVCFG_CPENA); |
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} |
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static int crunch_do(struct notifier_block *self, unsigned long cmd, void *t) |
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{ |
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struct thread_info *thread = (struct thread_info *)t; |
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struct crunch_state *crunch_state; |
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u32 devcfg; |
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crunch_state = &thread->crunchstate; |
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switch (cmd) { |
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case THREAD_NOTIFY_FLUSH: |
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memset(crunch_state, 0, sizeof(*crunch_state)); |
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/* |
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* FALLTHROUGH: Ensure we don't try to overwrite our newly |
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* initialised state information on the first fault. |
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*/ |
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fallthrough; |
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case THREAD_NOTIFY_EXIT: |
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crunch_task_release(thread); |
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break; |
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case THREAD_NOTIFY_SWITCH: |
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devcfg = __raw_readl(EP93XX_SYSCON_DEVCFG); |
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if (crunch_enabled(devcfg) || crunch_owner == crunch_state) { |
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/* |
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* We don't use ep93xx_syscon_swlocked_write() here |
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* because we are on the context switch path and |
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* preemption is already disabled. |
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*/ |
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devcfg ^= EP93XX_SYSCON_DEVCFG_CPENA; |
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__raw_writel(0xaa, EP93XX_SYSCON_SWLOCK); |
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__raw_writel(devcfg, EP93XX_SYSCON_DEVCFG); |
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} |
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break; |
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} |
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return NOTIFY_DONE; |
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} |
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static struct notifier_block crunch_notifier_block = { |
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.notifier_call = crunch_do, |
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}; |
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int __init crunch_init(void) |
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{ |
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thread_register_notifier(&crunch_notifier_block); |
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elf_hwcap |= HWCAP_CRUNCH; |
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return 0; |
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}
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