diff options
| -rw-r--r-- | arch/arm/include/asm/fiq.h | 5 | ||||
| -rw-r--r-- | arch/arm/kernel/fiq.c | 79 | ||||
| -rw-r--r-- | arch/arm/plat-s3c24xx/include/plat/irq.h | 21 | ||||
| -rw-r--r-- | arch/arm/plat-s3c24xx/irq.c | 48 |
4 files changed, 142 insertions, 11 deletions
diff --git a/arch/arm/include/asm/fiq.h b/arch/arm/include/asm/fiq.h index 2242ce22ec6..7ade2b8445d 100644 --- 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); diff --git a/arch/arm/kernel/fiq.c b/arch/arm/kernel/fiq.c index 6ff7919613d..c07691ef4c0 100644 --- 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 *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; diff --git a/arch/arm/plat-s3c24xx/include/plat/irq.h b/arch/arm/plat-s3c24xx/include/plat/irq.h index 69e1be8bec3..11a866466d8 100644 --- 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, 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)); @@ -45,6 +53,9 @@ 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 } @@ -53,8 +64,15 @@ 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)); @@ -63,6 +81,9 @@ 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 } diff --git a/arch/arm/plat-s3c24xx/irq.c b/arch/arm/plat-s3c24xx/irq.c index d02f5f02045..14aa528d985 100644 --- 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 = { @@ -559,26 +589,26 @@ 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; } |