diff options
Diffstat (limited to 'recipes/linux/linux-openmoko-2.6.30.4/013-fiq_c_handler.patch')
| -rw-r--r-- | recipes/linux/linux-openmoko-2.6.30.4/013-fiq_c_handler.patch | 286 |
1 files changed, 286 insertions, 0 deletions
diff --git a/recipes/linux/linux-openmoko-2.6.30.4/013-fiq_c_handler.patch b/recipes/linux/linux-openmoko-2.6.30.4/013-fiq_c_handler.patch new file mode 100644 index 0000000000..de12e10cd7 --- /dev/null +++ b/recipes/linux/linux-openmoko-2.6.30.4/013-fiq_c_handler.patch @@ -0,0 +1,286 @@ +--- a/arch/arm/kernel/fiq.c ++++ b/arch/arm/kernel/fiq.c +@@ -8,6 +8,8 @@ + * + * FIQ support re-written by Russell King to be more generic + * ++ * FIQ handler in C supoprt written by Andy Green <andy@openmoko.com> ++ * + * We now properly support a method by which the FIQ handlers can + * be stacked onto the vector. We still do not support sharing + * the FIQ vector itself. +@@ -124,6 +126,83 @@ void __naked get_fiq_regs(struct pt_regs + : "r" (®s->ARM_r8), "I" (PSR_I_BIT | PSR_F_BIT | FIQ_MODE)); + } + ++/* -------- FIQ handler in C --------- ++ * ++ * Major Caveats for using this ++ * --------------------------- ++ * * ++ * * 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. ++ */ ++ ++static void (*current_fiq_c_isr)(void); ++#define FIQ_C_ISR_STACK_SIZE 256 ++ ++static void __attribute__((naked)) __jump_to_isr(void) ++{ ++ asm __volatile__ ("mov pc, r8"); ++} ++ ++ ++static void __attribute__((naked)) __actual_isr(void) ++{ ++ asm __volatile__ ( ++ "stmdb sp!, {r0-r12, lr};" ++ "mov fp, sp;" ++ ); ++ ++ current_fiq_c_isr(); ++ ++ asm __volatile__ ( ++ "ldmia sp!, {r0-r12, lr};" ++ "subs pc, lr, #4;" ++ ); ++} ++ ++void set_fiq_c_handler(void (*isr)(void)) ++{ ++ struct pt_regs regs; ++ ++ memset(®s, 0, sizeof(regs)); ++ regs.ARM_r8 = (unsigned long) __actual_isr; ++ regs.ARM_sp = 0xffff001c + FIQ_C_ISR_STACK_SIZE; ++ ++ set_fiq_handler(__jump_to_isr, 4); ++ ++ current_fiq_c_isr = isr; ++ ++ set_fiq_regs(®s); ++} ++/* -------- FIQ handler in C ---------*/ ++ + int claim_fiq(struct fiq_handler *f) + { + int ret = 0; +--- a/arch/arm/include/asm/fiq.h ++++ b/arch/arm/include/asm/fiq.h +@@ -29,8 +29,9 @@ struct fiq_handler { + extern int claim_fiq(struct fiq_handler *f); + extern void release_fiq(struct fiq_handler *f); + extern void set_fiq_handler(void *start, unsigned int length); +-extern void set_fiq_regs(struct pt_regs *regs); +-extern void get_fiq_regs(struct pt_regs *regs); ++extern void set_fiq_c_handler(void (*handler)(void)); ++extern void __attribute__((naked)) set_fiq_regs(struct pt_regs *regs); ++extern void __attribute__((naked)) get_fiq_regs(struct pt_regs *regs); + extern void enable_fiq(int fiq); + extern void disable_fiq(int fiq); + +--- a/arch/arm/plat-s3c24xx/include/plat/irq.h ++++ b/arch/arm/plat-s3c24xx/include/plat/irq.h +@@ -12,6 +12,7 @@ + + #include <linux/io.h> + ++#include <mach/irqs.h> + #include <mach/hardware.h> + #include <mach/regs-irq.h> + #include <mach/regs-gpio.h> +@@ -31,8 +32,15 @@ s3c_irqsub_mask(unsigned int irqno, unsi + { + 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)); +@@ -45,6 +53,9 @@ s3c_irqsub_mask(unsigned int irqno, unsi + + /* write back masks */ + __raw_writel(submask, S3C2410_INTSUBMSK); ++#ifdef CONFIG_S3C2440_C_FIQ ++ local_irq_restore(flags); ++#endif + + } + +@@ -53,8 +64,15 @@ s3c_irqsub_unmask(unsigned int irqno, un + { + 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)); +@@ -63,6 +81,9 @@ s3c_irqsub_unmask(unsigned int irqno, un + /* write back masks */ + __raw_writel(submask, S3C2410_INTSUBMSK); + __raw_writel(mask, S3C2410_INTMSK); ++#ifdef CONFIG_S3C2440_C_FIQ ++ local_irq_restore(flags); ++#endif + } + + +--- a/arch/arm/plat-s3c24xx/irq.c ++++ b/arch/arm/plat-s3c24xx/irq.c +@@ -28,6 +28,8 @@ + #include <asm/mach/irq.h> + + #include <plat/regs-irqtype.h> ++#include <mach/regs-irq.h> ++#include <mach/regs-gpio.h> + + #include <plat/cpu.h> + #include <plat/pm.h> +@@ -37,12 +39,20 @@ 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 +@@ -59,9 +69,19 @@ 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); +@@ -72,15 +92,25 @@ 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 = { +@@ -523,26 +553,26 @@ void __init s3c24xx_init_irq(void) + + last = 0; + for (i = 0; i < 4; i++) { +- pend = __raw_readl(S3C2410_INTPND); ++ pend = __raw_readl(S3C2410_SUBSRCPND); + + if (pend == 0 || pend == last) + break; + +- __raw_writel(pend, S3C2410_SRCPND); +- __raw_writel(pend, S3C2410_INTPND); +- printk("irq: clearing pending status %08x\n", (int)pend); ++ printk("irq: clearing subpending status %08x\n", (int)pend); ++ __raw_writel(pend, S3C2410_SUBSRCPND); + last = pend; + } + + last = 0; + for (i = 0; i < 4; i++) { +- pend = __raw_readl(S3C2410_SUBSRCPND); ++ pend = __raw_readl(S3C2410_INTPND); + + if (pend == 0 || pend == last) + break; + +- printk("irq: clearing subpending status %08x\n", (int)pend); +- __raw_writel(pend, S3C2410_SUBSRCPND); ++ __raw_writel(pend, S3C2410_SRCPND); ++ __raw_writel(pend, S3C2410_INTPND); ++ printk("irq: clearing pending status %08x\n", (int)pend); + last = pend; + } + |