Re: [PATCH 08/56] microblaze_v2: Interrupt handling, timer support, supported function

Thomas Gleixner
2008-05-07T07:07:30Z

Michal,

On Sun, 4 May 2008, monstr@seznam.cz wrote:
> From: Michal Simek <monstr@monstr.eu>

> +/* NOTE
> + * self-modified part of code for improvement of interrupt controller
> + * save instruction in interrupt rutine
> + */
> +void function_hack(const int *arr_fce, const unsigned int base)
> +{
> + unsigned int flags = 0;

no need to initialize flags

> + unsigned int j, i;
> + unsigned int *addr = NULL;

Just a coding style nit:

unsigned int i, j, flags, *addr = NULL;

saves 2 lines of code :)

> + local_irq_save(flags);
> + __disable_icache();
> +
> + /* zero terminated array */
> + for (j = 0; arr_fce[j] != 0; j++) {
> + /* get start address of function */
> + addr = (unsigned int *) arr_fce[j];
> + pr_debug("%s: func(%d) at 0x%x\n",
> + __func__, j, (unsigned int) addr);
> + for (i = 0;; i++) {
> + pr_debug("%s: instruction code at %d: 0x%x\n",
> + __func__, i, addr[i]);
> + if (addr[i] == 0xb0001234) {

Please replace all those hex constants with proper named defines so
the code becomes readable

> + /* detecting of lwi or swi instruction */
> + if ((addr[i+1] & 0xec00ff00) == 0xe800ff00) {
> + pr_debug("%s: curr instr, "
> + "(%d):0x%x, "
> + "next(%d):0x%x\n",
> + __func__, i, addr[i], i+1,
> + addr[i+1]);
> + addr[i] = 0xb0000000 + (base >> 16);
> + addr[i+1] = (addr[i+1] & 0xffff00ff) +
> + (base & 0xffff);
> + __invalidate_icache(addr[i]);
> + __invalidate_icache(addr[i+1]);
> + pr_debug("%s: hack instr, "
> + "(%d):0x%x, "
> + "next(%d):0x%x\n",
> + __func__, i, addr[i], i+1,
> + addr[i+1]);

Please split this modification code out into a separate function. The
same code is used below.

> + } else /* detection addik for ack */
> + if ((addr[i+1] & 0xfc00ff00) == 0x3000ff00) {
> + pr_debug("%s: curr instr, "
> + "(%d):0x%x, "
> + "next(%d):0x%x\n",
> + __func__, i, addr[i], i+1,
> + addr[i+1]);
> + addr[i] = 0xb0000000 + (base >> 16);
> + addr[i+1] = (addr[i+1] & 0xffff00ff) +
> + (base & 0xffff);
> + __invalidate_icache(addr[i]);
> + __invalidate_icache(addr[i+1]);
> + pr_debug("%s: hack instr, "
> + "(%d):0x%x, "
> + "next(%d):0x%x\n",
> + __func__, i, addr[i], i+1,
> + addr[i+1]);
> + }

> +#include <linux/init.h>
> +#include <linux/irq.h>
> +#include <linux/autoconf.h>
> +#include <asm/page.h>
> +#include <asm/io.h>
> +
> +#include <asm/prom.h>
> +#include <asm/irq.h>
> +
> +#ifdef CONFIG_HACK
> +#include <asm/hack.h>
> +#else
> +static unsigned int intc_baseaddr;
> +#endif
> +
> +unsigned int NR_IRQ;

Please use lower case for variables

> +/* No one else should require these constants, so define them locally here. */
> +#define ISR 0x00 /* Interrupt Status Register */
> +#define IPR 0x04 /* Interrupt Pending Register */
> +#define IER 0x08 /* Interrupt Enable Register */
> +#define IAR 0x0c /* Interrupt Acknowledge Register */
> +#define SIE 0x10 /* Set Interrupt Enable bits */
> +#define CIE 0x14 /* Clear Interrupt Enable bits */
> +#define IVR 0x18 /* Interrupt Vector Register */
> +#define MER 0x1c /* Master Enable Register */
> +
> +#define MER_ME (1<<0)
> +#define MER_HIE (1<<1)
>
>
>
> +static void intc_enable(unsigned int irq)
> +{
> + unsigned int mask = (0x00000001 << (irq & 31));
> + pr_debug("enable: %d\n", irq);
> +#ifdef CONFIG_HACK

Please use a sensible name for that config switch and the constants
(e.g. HACK_BASE_ADDR)

> + iowrite32(mask, HACK_BASE_ADDR + SIE);
> +#else
> + iowrite32(mask, intc_baseaddr + SIE);
> +#endif

Please create a macro for that instead of uglyfying each function with
ifdeffery

#ifdef CONFIG_XXXX
# define INTC_BASE XXX_BASE_ADDR
#else
# define INTC_BASE intc_baseaddr
#endif

So now your functions reads simple:

unsigned int mask = (0x00000001 << (irq & 31));

iowrite32(mask, INTC_BASE_ADDR + SIE);

> +}
> +
> +static void intc_disable(unsigned int irq)
> +{
> + unsigned long mask = (0x00000001 << (irq & 31));
> + pr_debug("disable: %d\n", irq);
> +#ifdef CONFIG_HACK
> + iowrite32(mask, HACK_BASE_ADDR + CIE);
> +#else
> + iowrite32(mask, intc_baseaddr + CIE);
> +#endif
> +}
> +
> +static void intc_disable_and_ack(unsigned int irq)
> +{
> + unsigned long mask = (0x00000001 << (irq & 31));
> + pr_debug("disable_and_ack: %d\n", irq);
> +#ifdef CONFIG_HACK
> + iowrite32(mask, HACK_BASE_ADDR + CIE);
> + /* ack edge triggered intr */
> + if (!(irq_desc[irq].status & IRQ_LEVEL))
> + iowrite32(mask, HACK_BASE_ADDR + IAR);

Please do not do that. Create two irq_chips one for level and one for
edge with different implementations of the functions so you don't have
to check for level/edge in the functions itself.

> +
> + for (i = 0; i < NR_IRQ; ++i) {
> + irq_desc[i].chip = &intc_dev;
> +
> + if (handle & (0x00000001 << i))
> + irq_desc[i].status &= ~IRQ_LEVEL;
> + else
> + irq_desc[i].status |= IRQ_LEVEL;
> + }

With two irq chips this would be:

for (i = 0; i < NR_IRQ; ++i) {
if (handle & (0x00000001 << i)) {
set_irq_chip_and_handler(irq, &intc_edge, handle_edge_irq);
irq_desc[i].status &= ~IRQ_LEVEL;
} else {
set_irq_chip_and_handler(irq, &intc_level, handle_level_irq);
irq_desc[i].status |= IRQ_LEVEL;
}
}

> +}
> diff --git a/arch/microblaze/kernel/irq.c b/arch/microblaze/kernel/irq.c
> new file mode 100644
> index 0000000..4cd30aa
> --- /dev/null
> +++ b/arch/microblaze/kernel/irq.c
> @@ -0,0 +1,100 @@
> +/*
> + * arch/microblaze/kernel/process.c

Please remove those useless (and in this case even wrong) file names.

> +void do_IRQ(struct pt_regs *regs)
> +{
> + unsigned int irq;
> +
> + irq_enter();
> + set_irq_regs(regs);
> + irq = get_irq(regs);
> + BUG_ON(irq == -1U);
> + __do_IRQ(irq);

Please do not use __do_IRQ() use the handlers which provide per
interrupt type optimized handlers.

struct irq_desc *desc = irq_desc + irq;

desc->handle(irq);

> + irq_exit();
> +}

> +
> +/*unsigned int irq_of_parse_and_map(struct device_node *dev, int index)
> +{
> + printk ("ERROR %s\n",__FUNCTION__);
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(irq_of_parse_and_map);*/

Please remove unused code

> +static void timer_ack(void)
> +{
> +#ifdef CONFIG_HACK
> + iowrite32(ioread32(HACK_BASE_ADDR + TCSR0), HACK_BASE_ADDR + TCSR0);
> +#else
> + iowrite32(ioread32(timer_baseaddr + TCSR0), timer_baseaddr + TCSR0);
> +#endif

Same thing as the interrupt one

> +}
> +
> +irqreturn_t timer_interrupt(int irq, void *dev_id)
> +{
> +#ifdef CONFIG_HEART_BEAT
> + heartbeat();
> +#endif
> + timer_ack();
> +
> + write_seqlock(&xtime_lock);
> +
> + do_timer(1);

Can you please move a new architecture to clockevents / clocksource
right from the beginning ? No need to invent another incompatible set
of time(r) related functions.

> + update_process_times(user_mode(get_irq_regs()));
> + profile_tick(CPU_PROFILING);
> +
> + write_sequnlock(&xtime_lock);
> +
> + return IRQ_HANDLED;
> +}

> +/*
> + * HACK_BASE_ADDR is constant address for hack function.
> + * do not change this value - it is hardcoded in hack function
> + * arch/microblaze/kernel/hack.c:function_hack()

Grr. Please use defines for everything and do not hardcode stuff here
and there and make a define depend on some hardcoded value in a c
function.

> + */
> +
> +#define HACK_BASE_ADDR 0x1234ff00

> +#ifndef _ASM_MICROBLAZE_IRQ_H
> +#define _ASM_MICROBLAZE_IRQ_H
> +
> +#include <linux/seq_file.h>
> +#define NR_IRQS 32

Eeew.

> +#include <linux/irq.h>

asm/irq.h is included from linux/irq.h not the other way round

> +extern unsigned int NR_IRQ;
> +extern void ledoff(void);

Is ledoff an interrupt function ?

> +#define NO_IRQ (-1)
> +
> +static inline int irq_canonicalize(int irq)
> +{
> + return (irq);
> +}

Why is this needed ? Any users ?

> +struct pt_regs;
> +extern void do_IRQ(struct pt_regs *regs);
> +extern void __init init_IRQ(void);

> +int show_interrupts(struct seq_file *p, void *v);

Already defined in include/linux/interrupt.h

Thanks,
tglx