aboutsummaryrefslogtreecommitdiffstats
path: root/target/linux/s3c24xx/patches-2.6.26/0045-introduce-fiq-basis.patch.patch
diff options
context:
space:
mode:
Diffstat (limited to 'target/linux/s3c24xx/patches-2.6.26/0045-introduce-fiq-basis.patch.patch')
-rwxr-xr-xtarget/linux/s3c24xx/patches-2.6.26/0045-introduce-fiq-basis.patch.patch587
1 files changed, 587 insertions, 0 deletions
diff --git a/target/linux/s3c24xx/patches-2.6.26/0045-introduce-fiq-basis.patch.patch b/target/linux/s3c24xx/patches-2.6.26/0045-introduce-fiq-basis.patch.patch
new file mode 100755
index 0000000000..7b79d8ef81
--- /dev/null
+++ b/target/linux/s3c24xx/patches-2.6.26/0045-introduce-fiq-basis.patch.patch
@@ -0,0 +1,587 @@
+From 6a2c7de90f47b7eb74f3cb2d181f950ece22b3fb Mon Sep 17 00:00:00 2001
+From: mokopatches <mokopatches@openmoko.org>
+Date: Fri, 25 Jul 2008 22:21:22 +0100
+Subject: [PATCH] introduce-fiq-basis.patch
+ Adds a C-based FIQ ISR which is very convenient (and unusual --
+ normally you have to do FIQ ISR in assembler only).
+ Based on my article:
+
+http://warmcat.com/_wp/2007/09/17/at91rm9200-fiq-faq-and-simple-example-code-patch/
+
+Implemented as a platform device and driver.
+
+Suspend / resume is tested and works.
+
+Signed-off-by: Andy Green <andy@warmcat.com>
+---
+ arch/arm/mach-s3c2440/Kconfig | 7 +
+ arch/arm/mach-s3c2440/Makefile | 1 +
+ arch/arm/mach-s3c2440/fiq_c_isr.c | 250 ++++++++++++++++++++++++++
+ arch/arm/mach-s3c2440/fiq_c_isr.h | 64 +++++++
+ arch/arm/mach-s3c2440/mach-gta02.c | 22 +++
+ arch/arm/plat-s3c24xx/irq.c | 32 +++-
+ include/asm-arm/arch-s3c2410/fiq_ipc_gta02.h | 28 +++
+ include/asm-arm/plat-s3c24xx/irq.h | 20 ++
+ 8 files changed, 422 insertions(+), 2 deletions(-)
+ create mode 100644 arch/arm/mach-s3c2440/fiq_c_isr.c
+ create mode 100644 arch/arm/mach-s3c2440/fiq_c_isr.h
+ create mode 100644 include/asm-arm/arch-s3c2410/fiq_ipc_gta02.h
+
+diff --git a/arch/arm/mach-s3c2440/Kconfig b/arch/arm/mach-s3c2440/Kconfig
+index 6b317d1..3015aaf 100644
+--- a/arch/arm/mach-s3c2440/Kconfig
++++ b/arch/arm/mach-s3c2440/Kconfig
+@@ -22,6 +22,13 @@ config S3C2440_DMA
+ help
+ Support for S3C2440 specific DMA code5A
+
++config S3C2440_C_FIQ
++ bool "FIQ ISR support in C"
++ depends on ARCH_S3C2410
++ select FIQ
++ help
++ Support for S3C2440 FIQ support in C -- see
++ ./arch/arm/macs3c2440/fiq_c_isr.c
+
+ menu "S3C2440 Machines"
+
+diff --git a/arch/arm/mach-s3c2440/Makefile b/arch/arm/mach-s3c2440/Makefile
+index 1a4defd..4932232 100644
+--- a/arch/arm/mach-s3c2440/Makefile
++++ b/arch/arm/mach-s3c2440/Makefile
+@@ -13,6 +13,7 @@ obj-$(CONFIG_CPU_S3C2440) += s3c2440.o dsc.o
+ obj-$(CONFIG_CPU_S3C2440) += irq.o
+ obj-$(CONFIG_CPU_S3C2440) += clock.o
+ obj-$(CONFIG_S3C2440_DMA) += dma.o
++obj-$(CONFIG_S3C2440_C_FIQ) += fiq_c_isr.o
+
+ # Machine support
+
+diff --git a/arch/arm/mach-s3c2440/fiq_c_isr.c b/arch/arm/mach-s3c2440/fiq_c_isr.c
+new file mode 100644
+index 0000000..12f4527
+--- /dev/null
++++ b/arch/arm/mach-s3c2440/fiq_c_isr.c
+@@ -0,0 +1,250 @@
++/*
++ * Copyright 2007 Andy Green <andy@warmcat.com>
++ * S3C modfifications
++ * Copyright 2008 Andy Green <andy@openmoko.com>
++ */
++
++#include <linux/module.h>
++#include <linux/kernel.h>
++#include <asm/hardware.h>
++#include <asm/fiq.h>
++#include "fiq_c_isr.h"
++#include <linux/sysfs.h>
++#include <linux/device.h>
++#include <linux/platform_device.h>
++
++#include <asm/io.h>
++
++#include <asm/plat-s3c24xx/cpu.h>
++#include <asm/plat-s3c24xx/irq.h>
++
++/*
++ * Major Caveats for using FIQ
++ * ---------------------------
++ *
++ * 1) it CANNOT touch any vmalloc()'d memory, only memory
++ * that was kmalloc()'d. Static allocations in the monolithic kernel
++ * are kmalloc()'d so they are okay. You can touch memory-mapped IO, but
++ * the pointer for it has to have been stored in kmalloc'd memory. The
++ * reason for this is simple: every now and then Linux turns off interrupts
++ * and reorders the paging tables. If a FIQ happens during this time, the
++ * virtual memory space can be partly or entirely disordered or missing.
++ *
++ * 2) Because vmalloc() is used when a module is inserted, THIS FIQ
++ * ISR HAS TO BE IN THE MONOLITHIC KERNEL, not a module. But the way
++ * it is set up, you can all to enable and disable it from your module
++ * and intercommunicate with it through struct fiq_ipc
++ * fiq_ipc which you can define in
++ * asm/archfiq_ipc_type.h. The reason is the same as above, a
++ * FIQ could happen while even the ISR is not present in virtual memory
++ * space due to pagetables being changed at the time.
++ *
++ * 3) You can't call any Linux API code except simple macros
++ * - understand that FIQ can come in at any time, no matter what
++ * state of undress the kernel may privately be in, thinking it
++ * locked the door by turning off interrupts... FIQ is an
++ * unstoppable monster force (which is its value)
++ * - they are not vmalloc()'d memory safe
++ * - they might do crazy stuff like sleep: FIQ pisses fire and
++ * is not interested in 'sleep' that the weak seem to need
++ * - calling APIs from FIQ can re-enter un-renterable things
++ * - summary: you cannot interoperate with linux APIs directly in the FIQ ISR
++ *
++ * If you follow these rules, it is fantastic, an extremely powerful, solid,
++ * genuine hard realtime feature.
++ *
++ */
++
++/* more than enough to cover our jump instruction to the isr */
++#define SIZEOF_FIQ_JUMP 8
++/* more than enough to cover s3c2440_fiq_isr() in 4K blocks */
++#define SIZEOF_FIQ_ISR 0x2000
++/* increase the size of the stack that is active during FIQ as needed */
++static u8 u8aFiqStack[4096];
++
++/* only one FIQ ISR possible, okay to do these here */
++u32 _fiq_ack_mask; /* used by isr exit define */
++unsigned long _fiq_count_fiqs; /* used by isr exit define */
++static int _fiq_irq; /* private ; irq index we were started with, or 0 */
++
++/* this function must live in the monolithic kernel somewhere! A module is
++ * NOT good enough!
++ */
++extern void __attribute__ ((naked)) s3c2440_fiq_isr(void);
++
++/* this is copied into the hard FIQ vector during init */
++
++static void __attribute__ ((naked)) s3c2440_FIQ_Branch(void)
++{
++ asm __volatile__ (
++ "mov pc, r8 ; "
++ );
++}
++
++/* sysfs */
++
++static ssize_t show_count(struct device *dev, struct device_attribute *attr,
++ char *buf)
++{
++ return sprintf(buf, "%ld\n", _fiq_count_fiqs);
++}
++
++static DEVICE_ATTR(count, 0444, show_count, NULL);
++
++static struct attribute *s3c2440_fiq_sysfs_entries[] = {
++ &dev_attr_count.attr,
++ NULL
++};
++
++static struct attribute_group s3c2440_fiq_attr_group = {
++ .name = "fiq",
++ .attrs = s3c2440_fiq_sysfs_entries,
++};
++
++/*
++ * call this from your kernel module to set up the FIQ ISR to service FIQs,
++ * You need to have configured your FIQ input pin before anything will happen
++ *
++ * call it with, eg, IRQ_TIMER3 from asm-arm/arch-s3c2410/irqs.h
++ *
++ * you still need to clear the source interrupt in S3C2410_INTMSK to get
++ * anything good happening
++ */
++static void fiq_init_irq_source(int irq_index_fiq)
++{
++ if (!irq_index_fiq) /* no interrupt */
++ return;
++
++ printk(KERN_INFO"Enabling FIQ using int idx %d\n",
++ irq_index_fiq - S3C2410_CPUIRQ_OFFSET);
++ local_fiq_disable();
++
++ _fiq_irq = irq_index_fiq;
++ _fiq_ack_mask = 1 << (irq_index_fiq - S3C2410_CPUIRQ_OFFSET);
++
++ /* let our selected interrupt be a magic FIQ interrupt */
++ __raw_writel(_fiq_ack_mask, S3C2410_INTMOD);
++
++ /* it's ready to go as soon as we unmask the source in S3C2410_INTMSK */
++ local_fiq_enable();
++}
++
++
++/* call this from your kernel module to disable generation of FIQ actions */
++static void fiq_disable_irq_source(void)
++{
++ /* nothing makes FIQ any more */
++ __raw_writel(0, S3C2410_INTMOD);
++ local_fiq_disable();
++ _fiq_irq = 0; /* no active source interrupt now either */
++}
++
++/* this starts FIQ timer events... they continue until the FIQ ISR sees that
++ * its work is done and it turns off the timer. After setting up the fiq_ipc
++ * struct with new work, you call this to start FIQ timer actions up again.
++ * Only the FIQ ISR decides when it is done and controls turning off the
++ * timer events.
++ */
++void fiq_kick(void)
++{
++ unsigned long flags;
++
++ /* we have to take care about FIQ because this modification is
++ * non-atomic, FIQ could come in after the read and before the
++ * writeback and its changes to the register would be lost
++ * (platform INTMSK mod code is taken care of already)
++ */
++ local_save_flags(flags);
++ local_fiq_disable();
++ __raw_writel(__raw_readl(S3C2410_INTMSK) &
++ ~(1 << (_fiq_irq - S3C2410_CPUIRQ_OFFSET)),
++ S3C2410_INTMSK);
++ local_irq_restore(flags);
++}
++EXPORT_SYMBOL_GPL(fiq_kick);
++
++
++
++static int __init sc32440_fiq_probe(struct platform_device *pdev)
++{
++ struct resource *r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
++
++ if (!r)
++ return -EIO;
++ /* configure for the interrupt we are meant to use */
++ fiq_init_irq_source(r->start);
++
++ return sysfs_create_group(&pdev->dev.kobj, &s3c2440_fiq_attr_group);
++}
++
++static int sc32440_fiq_remove(struct platform_device *pdev)
++{
++ fiq_disable_irq_source();
++ sysfs_remove_group(&pdev->dev.kobj, &s3c2440_fiq_attr_group);
++ return 0;
++}
++
++static void fiq_set_vector_and_regs(void)
++{
++ struct pt_regs regs;
++
++ /* prep the special FIQ mode regs */
++ memset(&regs, 0, sizeof(regs));
++ regs.ARM_r8 = (unsigned long)s3c2440_fiq_isr;
++ regs.ARM_sp = (unsigned long)u8aFiqStack + sizeof(u8aFiqStack) - 4;
++ /* set up the special FIQ-mode-only registers from our regs */
++ set_fiq_regs(&regs);
++ /* copy our jump to the real ISR into the hard vector address */
++ set_fiq_handler(s3c2440_FIQ_Branch, SIZEOF_FIQ_JUMP);
++}
++
++#ifdef CONFIG_PM
++static int sc32440_fiq_suspend(struct platform_device *pdev, pm_message_t state)
++{
++ /* nothing makes FIQ any more */
++ __raw_writel(0, S3C2410_INTMOD);
++ local_fiq_disable();
++
++ return 0;
++}
++
++static int sc32440_fiq_resume(struct platform_device *pdev)
++{
++ fiq_set_vector_and_regs();
++ fiq_init_irq_source(_fiq_irq);
++ return 0;
++}
++#else
++#define sc32440_fiq_suspend NULL
++#define sc32440_fiq_resume NULL
++#endif
++
++static struct platform_driver sc32440_fiq_driver = {
++ .driver = {
++ .name = "sc32440_fiq",
++ .owner = THIS_MODULE,
++ },
++
++ .probe = sc32440_fiq_probe,
++ .remove = __devexit_p(sc32440_fiq_remove),
++ .suspend = sc32440_fiq_suspend,
++ .resume = sc32440_fiq_resume,
++};
++
++static int __init sc32440_fiq_init(void)
++{
++ fiq_set_vector_and_regs();
++
++ return platform_driver_register(&sc32440_fiq_driver);
++}
++
++static void __exit sc32440_fiq_exit(void)
++{
++ fiq_disable_irq_source();
++}
++
++MODULE_AUTHOR("Andy Green <andy@openmoko.com>");
++MODULE_LICENSE("GPL");
++
++module_init(sc32440_fiq_init);
++module_exit(sc32440_fiq_exit);
+diff --git a/arch/arm/mach-s3c2440/fiq_c_isr.h b/arch/arm/mach-s3c2440/fiq_c_isr.h
+new file mode 100644
+index 0000000..f08740e
+--- /dev/null
++++ b/arch/arm/mach-s3c2440/fiq_c_isr.h
+@@ -0,0 +1,64 @@
++#ifndef _LINUX_FIQ_C_ISR_H
++#define _LINUX_FIQ_C_ISR_H
++
++#include <asm/arch-s3c2410/regs-irq.h>
++
++extern unsigned long _fiq_count_fiqs;
++extern u32 _fiq_ack_mask;
++
++/* This CANNOT be implemented in a module -- it has to be used in code
++ * included in the monolithic kernel
++ */
++
++#define FIQ_HANDLER_START() \
++void __attribute__ ((naked)) s3c2440_fiq_isr(void) \
++{\
++ /*\
++ * you can declare local vars here, take care to set the frame size\
++ * below accordingly if there are more than a few dozen bytes of them\
++ */\
++
++/* stick your locals here :-)
++ * Do NOT initialize them here! define them and initialize them after
++ * FIQ_HANDLER_ENTRY() is done.
++ */
++
++#define FIQ_HANDLER_ENTRY(LOCALS, FRAME) \
++ const int _FIQ_FRAME_SIZE = FRAME; \
++ /* entry takes care to store registers we will be treading on here */\
++ asm __volatile__ (\
++ "mov ip, sp ;"\
++ /* stash FIQ and r0-r8 normal regs */\
++ "stmdb sp!, {r0-r12, lr};"\
++ /* allow SP to get some space */\
++ "sub sp, sp, %1 ;"\
++ /* !! THIS SETS THE FRAME, adjust to > sizeof locals */\
++ "sub fp, sp, %0 ;"\
++ :\
++ : "rI" (LOCALS), "rI" (FRAME)\
++ :"r9"\
++ );
++
++/* stick your ISR code here and then end with... */
++
++#define FIQ_HANDLER_END() \
++ _fiq_count_fiqs++;\
++ __raw_writel(_fiq_ack_mask, S3C2410_SRCPND);\
++\
++ /* exit back to normal mode restoring everything */\
++ asm __volatile__ (\
++ /* pop our allocation */\
++ "add sp, sp, %0 ;"\
++ /* return FIQ regs back to pristine state\
++ * and get normal regs back\
++ */\
++ "ldmia sp!, {r0-r12, lr};"\
++\
++ /* return */\
++ "subs pc, lr, #4;"\
++ : \
++ : "rI" (_FIQ_FRAME_SIZE) \
++ );\
++}
++
++#endif /* _LINUX_FIQ_C_ISR_H */
+diff --git a/arch/arm/mach-s3c2440/mach-gta02.c b/arch/arm/mach-s3c2440/mach-gta02.c
+index 46acede..0bdd0e0 100644
+--- a/arch/arm/mach-s3c2440/mach-gta02.c
++++ b/arch/arm/mach-s3c2440/mach-gta02.c
+@@ -78,9 +78,31 @@
+
+ #include <linux/glamofb.h>
+
++#include <asm/arch/fiq_ipc_gta02.h>
++#include "fiq_c_isr.h"
++
+ /* arbitrates which sensor IRQ owns the shared SPI bus */
+ static spinlock_t motion_irq_lock;
+
++/* define FIQ IPC struct */
++/*
++ * contains stuff FIQ ISR modifies and normal kernel code can see and use
++ * this is defined in <asm/arch/fiq_ipc_gta02.h>, you should customize
++ * the definition in there and include the same definition in your kernel
++ * module that wants to interoperate with your FIQ code.
++ */
++struct fiq_ipc fiq_ipc;
++EXPORT_SYMBOL(fiq_ipc);
++
++/* define FIQ ISR */
++
++FIQ_HANDLER_START()
++/* define your locals here -- no initializers though */
++FIQ_HANDLER_ENTRY(256, 512)
++/* Your ISR here :-) */
++FIQ_HANDLER_END()
++
++
+ static struct map_desc gta02_iodesc[] __initdata = {
+ {
+ .virtual = 0xe0000000,
+diff --git a/arch/arm/plat-s3c24xx/irq.c b/arch/arm/plat-s3c24xx/irq.c
+index ae2c5d7..9887db1 100644
+--- a/arch/arm/plat-s3c24xx/irq.c
++++ b/arch/arm/plat-s3c24xx/irq.c
+@@ -133,12 +133,20 @@ static void
+ s3c_irq_mask(unsigned int irqno)
+ {
+ unsigned long mask;
+-
++#ifdef CONFIG_S3C2440_C_FIQ
++ unsigned long flags;
++#endif
+ irqno -= IRQ_EINT0;
+-
++#ifdef CONFIG_S3C2440_C_FIQ
++ local_save_flags(flags);
++ local_fiq_disable();
++#endif
+ mask = __raw_readl(S3C2410_INTMSK);
+ mask |= 1UL << irqno;
+ __raw_writel(mask, S3C2410_INTMSK);
++#ifdef CONFIG_S3C2440_C_FIQ
++ local_irq_restore(flags);
++#endif
+ }
+
+ static inline void
+@@ -155,9 +163,19 @@ s3c_irq_maskack(unsigned int irqno)
+ {
+ unsigned long bitval = 1UL << (irqno - IRQ_EINT0);
+ unsigned long mask;
++#ifdef CONFIG_S3C2440_C_FIQ
++ unsigned long flags;
++#endif
+
++#ifdef CONFIG_S3C2440_C_FIQ
++ local_save_flags(flags);
++ local_fiq_disable();
++#endif
+ mask = __raw_readl(S3C2410_INTMSK);
+ __raw_writel(mask|bitval, S3C2410_INTMSK);
++#ifdef CONFIG_S3C2440_C_FIQ
++ local_irq_restore(flags);
++#endif
+
+ __raw_writel(bitval, S3C2410_SRCPND);
+ __raw_writel(bitval, S3C2410_INTPND);
+@@ -168,15 +186,25 @@ static void
+ s3c_irq_unmask(unsigned int irqno)
+ {
+ unsigned long mask;
++#ifdef CONFIG_S3C2440_C_FIQ
++ unsigned long flags;
++#endif
+
+ if (irqno != IRQ_TIMER4 && irqno != IRQ_EINT8t23)
+ irqdbf2("s3c_irq_unmask %d\n", irqno);
+
+ irqno -= IRQ_EINT0;
+
++#ifdef CONFIG_S3C2440_C_FIQ
++ local_save_flags(flags);
++ local_fiq_disable();
++#endif
+ mask = __raw_readl(S3C2410_INTMSK);
+ mask &= ~(1UL << irqno);
+ __raw_writel(mask, S3C2410_INTMSK);
++#ifdef CONFIG_S3C2440_C_FIQ
++ local_irq_restore(flags);
++#endif
+ }
+
+ struct irq_chip s3c_irq_level_chip = {
+diff --git a/include/asm-arm/arch-s3c2410/fiq_ipc_gta02.h b/include/asm-arm/arch-s3c2410/fiq_ipc_gta02.h
+new file mode 100644
+index 0000000..341f2bb
+--- /dev/null
++++ b/include/asm-arm/arch-s3c2410/fiq_ipc_gta02.h
+@@ -0,0 +1,28 @@
++#ifndef _LINUX_FIQ_IPC_H
++#define _LINUX_FIQ_IPC_H
++
++/*
++ * this defines the struct which is used to communicate between the FIQ
++ * world and the normal linux kernel world. One of these structs is
++ * statically defined for you in the monolithic kernel so the FIQ ISR code
++ * can safely touch it any any time.
++ *
++ * You also want to include this file in your kernel module that wants to
++ * communicate with your FIQ code. Add any kinds of vars that are used by
++ * the FIQ ISR and the module in here.
++ *
++ * To get you started there is just an int that is incremented every FIQ
++ * you can remove this when you are ready to customize, but it is useful
++ * for testing
++ */
++
++struct fiq_ipc {
++ u8 u8a[0]; /* placeholder */
++};
++
++/* actual definition lives in arch/arm/mach-s3c2440/fiq_c_isr.c */
++extern struct fiq_ipc fiq_ipc;
++
++extern void fiq_kick(void); /* provoke a FIQ "immediately" */
++
++#endif /* _LINUX_FIQ_IPC_H */
+diff --git a/include/asm-arm/plat-s3c24xx/irq.h b/include/asm-arm/plat-s3c24xx/irq.h
+index 45746a9..bf15e1c 100644
+--- a/include/asm-arm/plat-s3c24xx/irq.h
++++ b/include/asm-arm/plat-s3c24xx/irq.h
+@@ -25,8 +25,15 @@ s3c_irqsub_mask(unsigned int irqno, unsigned int parentbit,
+ {
+ unsigned long mask;
+ unsigned long submask;
++#ifdef CONFIG_S3C2440_C_FIQ
++ unsigned long flags;
++#endif
+
+ submask = __raw_readl(S3C2410_INTSUBMSK);
++#ifdef CONFIG_S3C2440_C_FIQ
++ local_save_flags(flags);
++ local_fiq_disable();
++#endif
+ mask = __raw_readl(S3C2410_INTMSK);
+
+ submask |= (1UL << (irqno - IRQ_S3CUART_RX0));
+@@ -39,6 +46,9 @@ s3c_irqsub_mask(unsigned int irqno, unsigned int parentbit,
+
+ /* write back masks */
+ __raw_writel(submask, S3C2410_INTSUBMSK);
++#ifdef CONFIG_S3C2440_C_FIQ
++ local_irq_restore(flags);
++#endif
+
+ }
+
+@@ -47,8 +57,15 @@ s3c_irqsub_unmask(unsigned int irqno, unsigned int parentbit)
+ {
+ unsigned long mask;
+ unsigned long submask;
++#ifdef CONFIG_S3C2440_C_FIQ
++ unsigned long flags;
++#endif
+
+ submask = __raw_readl(S3C2410_INTSUBMSK);
++#ifdef CONFIG_S3C2440_C_FIQ
++ local_save_flags(flags);
++ local_fiq_disable();
++#endif
+ mask = __raw_readl(S3C2410_INTMSK);
+
+ submask &= ~(1UL << (irqno - IRQ_S3CUART_RX0));
+@@ -57,6 +74,9 @@ s3c_irqsub_unmask(unsigned int irqno, unsigned int parentbit)
+ /* write back masks */
+ __raw_writel(submask, S3C2410_INTSUBMSK);
+ __raw_writel(mask, S3C2410_INTMSK);
++#ifdef CONFIG_S3C2440_C_FIQ
++ local_irq_restore(flags);
++#endif
+ }
+
+
+--
+1.5.6.3
+