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From 4d0c4173b78783599053992b5994798a1a62df1c Mon Sep 17 00:00:00 2001
From: Andrei Warkentin <andrey.warkentin@gmail.com>
Date: Sun, 25 Sep 2011 03:34:39 -0400
Subject: [PATCH 2/7] ARM: Add Google FIQ glue code.
This lets easily write code that runs in FIQ mode.
Signed-off-by: Andrei Warkentin <andrey.warkentin@gmail.com>
---
arch/arm/common/Kconfig | 4 ++
arch/arm/common/Makefile | 1 +
arch/arm/common/fiq_glue.S | 111 ++++++++++++++++++++++++++++++++++++++
arch/arm/common/fiq_glue_setup.c | 100 ++++++++++++++++++++++++++++++++++
arch/arm/include/asm/fiq_glue.h | 30 ++++++++++
5 files changed, 246 insertions(+), 0 deletions(-)
create mode 100644 arch/arm/common/fiq_glue.S
create mode 100644 arch/arm/common/fiq_glue_setup.c
create mode 100644 arch/arm/include/asm/fiq_glue.h
diff --git a/arch/arm/common/Kconfig b/arch/arm/common/Kconfig
index 4b71766..897b3fb 100644
--- a/arch/arm/common/Kconfig
+++ b/arch/arm/common/Kconfig
@@ -39,3 +39,7 @@ config SHARP_PARAM
config SHARP_SCOOP
bool
+
+config FIQ_GLUE
+ bool
+ select FIQ
diff --git a/arch/arm/common/Makefile b/arch/arm/common/Makefile
index 6ea9b6f..0ca99bb 100644
--- a/arch/arm/common/Makefile
+++ b/arch/arm/common/Makefile
@@ -17,3 +17,4 @@ obj-$(CONFIG_ARCH_IXP2000) += uengine.o
obj-$(CONFIG_ARCH_IXP23XX) += uengine.o
obj-$(CONFIG_PCI_HOST_ITE8152) += it8152.o
obj-$(CONFIG_ARM_TIMER_SP804) += timer-sp.o
+obj-$(CONFIG_FIQ_GLUE) += fiq_glue.o fiq_glue_setup.o
diff --git a/arch/arm/common/fiq_glue.S b/arch/arm/common/fiq_glue.S
new file mode 100644
index 0000000..9e3455a
--- /dev/null
+++ b/arch/arm/common/fiq_glue.S
@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2008 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ *
+ */
+
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+
+ .text
+
+ .global fiq_glue_end
+
+ /* fiq stack: r0-r15,cpsr,spsr of interrupted mode */
+
+ENTRY(fiq_glue)
+ /* store pc, cpsr from previous mode */
+ mrs r12, spsr
+ sub r11, lr, #4
+ subs r10, #1
+ bne nested_fiq
+
+ stmfd sp!, {r11-r12, lr}
+
+ /* store r8-r14 from previous mode */
+ sub sp, sp, #(7 * 4)
+ stmia sp, {r8-r14}^
+ nop
+
+ /* store r0-r7 from previous mode */
+ stmfd sp!, {r0-r7}
+
+ /* setup func(data,regs) arguments */
+ mov r0, r9
+ mov r1, sp
+ mov r3, r8
+
+ mov r7, sp
+
+ /* Get sp and lr from non-user modes */
+ and r4, r12, #MODE_MASK
+ cmp r4, #USR_MODE
+ beq fiq_from_usr_mode
+
+ mov r7, sp
+ orr r4, r4, #(PSR_I_BIT | PSR_F_BIT)
+ msr cpsr_c, r4
+ str sp, [r7, #(4 * 13)]
+ str lr, [r7, #(4 * 14)]
+ mrs r5, spsr
+ str r5, [r7, #(4 * 17)]
+
+ cmp r4, #(SVC_MODE | PSR_I_BIT | PSR_F_BIT)
+ /* use fiq stack if we reenter this mode */
+ subne sp, r7, #(4 * 3)
+
+fiq_from_usr_mode:
+ msr cpsr_c, #(SVC_MODE | PSR_I_BIT | PSR_F_BIT)
+ mov r2, sp
+ sub sp, r7, #12
+ stmfd sp!, {r2, ip, lr}
+ /* call func(data,regs) */
+ blx r3
+ ldmfd sp, {r2, ip, lr}
+ mov sp, r2
+
+ /* restore/discard saved state */
+ cmp r4, #USR_MODE
+ beq fiq_from_usr_mode_exit
+
+ msr cpsr_c, r4
+ ldr sp, [r7, #(4 * 13)]
+ ldr lr, [r7, #(4 * 14)]
+ msr spsr_cxsf, r5
+
+fiq_from_usr_mode_exit:
+ msr cpsr_c, #(FIQ_MODE | PSR_I_BIT | PSR_F_BIT)
+
+ ldmfd sp!, {r0-r7}
+ add sp, sp, #(7 * 4)
+ ldmfd sp!, {r11-r12, lr}
+exit_fiq:
+ msr spsr_cxsf, r12
+ add r10, #1
+ movs pc, r11
+
+nested_fiq:
+ orr r12, r12, #(PSR_F_BIT)
+ b exit_fiq
+
+fiq_glue_end:
+
+ENTRY(fiq_glue_setup) /* func, data, sp */
+ mrs r3, cpsr
+ msr cpsr_c, #(FIQ_MODE | PSR_I_BIT | PSR_F_BIT)
+ movs r8, r0
+ mov r9, r1
+ mov sp, r2
+ moveq r10, #0
+ movne r10, #1
+ msr cpsr_c, r3
+ bx lr
+
diff --git a/arch/arm/common/fiq_glue_setup.c b/arch/arm/common/fiq_glue_setup.c
new file mode 100644
index 0000000..4044c7d
--- /dev/null
+++ b/arch/arm/common/fiq_glue_setup.c
@@ -0,0 +1,100 @@
+/*
+ * Copyright (C) 2010 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/percpu.h>
+#include <linux/slab.h>
+#include <asm/fiq.h>
+#include <asm/fiq_glue.h>
+
+extern unsigned char fiq_glue, fiq_glue_end;
+extern void fiq_glue_setup(void *func, void *data, void *sp);
+
+static struct fiq_handler fiq_debbuger_fiq_handler = {
+ .name = "fiq_glue",
+};
+DEFINE_PER_CPU(void *, fiq_stack);
+static struct fiq_glue_handler *current_handler;
+static DEFINE_MUTEX(fiq_glue_lock);
+
+static void fiq_glue_setup_helper(void *info)
+{
+ struct fiq_glue_handler *handler = info;
+ fiq_glue_setup(handler->fiq, handler,
+ __get_cpu_var(fiq_stack) + THREAD_START_SP);
+}
+
+int fiq_glue_register_handler(struct fiq_glue_handler *handler)
+{
+ int ret;
+ int cpu;
+
+ if (!handler || !handler->fiq)
+ return -EINVAL;
+
+ mutex_lock(&fiq_glue_lock);
+ if (fiq_stack) {
+ ret = -EBUSY;
+ goto err_busy;
+ }
+
+ for_each_possible_cpu(cpu) {
+ void *stack;
+ stack = (void *)__get_free_pages(GFP_KERNEL, THREAD_SIZE_ORDER);
+ if (WARN_ON(!stack)) {
+ ret = -ENOMEM;
+ goto err_alloc_fiq_stack;
+ }
+ per_cpu(fiq_stack, cpu) = stack;
+ }
+
+ ret = claim_fiq(&fiq_debbuger_fiq_handler);
+ if (WARN_ON(ret))
+ goto err_claim_fiq;
+
+ current_handler = handler;
+ on_each_cpu(fiq_glue_setup_helper, handler, true);
+ set_fiq_handler(&fiq_glue, &fiq_glue_end - &fiq_glue);
+
+ mutex_unlock(&fiq_glue_lock);
+ return 0;
+
+err_claim_fiq:
+err_alloc_fiq_stack:
+ for_each_possible_cpu(cpu) {
+ __free_pages(per_cpu(fiq_stack, cpu), THREAD_SIZE_ORDER);
+ per_cpu(fiq_stack, cpu) = NULL;
+ }
+err_busy:
+ mutex_unlock(&fiq_glue_lock);
+ return ret;
+}
+
+/**
+ * fiq_glue_resume - Restore fiqs after suspend or low power idle states
+ *
+ * This must be called before calling local_fiq_enable after returning from a
+ * power state where the fiq mode registers were lost. If a driver provided
+ * a resume hook when it registered the handler it will be called.
+ */
+
+void fiq_glue_resume(void)
+{
+ if (!current_handler)
+ return;
+ fiq_glue_setup(current_handler->fiq, current_handler,
+ __get_cpu_var(fiq_stack) + THREAD_START_SP);
+ if (current_handler->resume)
+ current_handler->resume(current_handler);
+}
+
diff --git a/arch/arm/include/asm/fiq_glue.h b/arch/arm/include/asm/fiq_glue.h
new file mode 100644
index 0000000..d54c29d
--- /dev/null
+++ b/arch/arm/include/asm/fiq_glue.h
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2010 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ */
+
+#ifndef __ASM_FIQ_GLUE_H
+#define __ASM_FIQ_GLUE_H
+
+struct fiq_glue_handler {
+ void (*fiq)(struct fiq_glue_handler *h, void *regs, void *svc_sp);
+ void (*resume)(struct fiq_glue_handler *h);
+};
+
+int fiq_glue_register_handler(struct fiq_glue_handler *handler);
+
+#ifdef CONFIG_FIQ_GLUE
+void fiq_glue_resume(void);
+#else
+static inline void fiq_glue_resume(void) {}
+#endif
+
+#endif
--
1.7.6.1