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OMAP clock/hwmod: fix off-by-one errors 

Fix loop bailout off-by-one bugs reported by Juha Leppänen
<juha_motorsportcom@luukku.com>.

This second version incorporates comments from Russell King
<linux@arm.linux.org.uk>.  A new macro, 'omap_test_timeout', has
been created, with cleaner code, and existing code has been converted
to use it.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Juha Leppänen <juha_motorsportcom@luukku.com>
Cc: Russell King <linux@arm.linux.org.uk>
This commit is contained in:
Paul Walmsley 2009-12-08 16:33:16 -07:00 committed by paul
parent 3863c74b51
commit 6f8b7ff5b0
4 changed files with 31 additions and 14 deletions
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7
arch/arm/mach-omap2/cm.c
View File

@ -21,6 +21,8 @@
#include <asm/atomic.h> #include <asm/atomic.h>
#include <plat/common.h>
#include "cm.h" #include "cm.h"
#include "cm-regbits-24xx.h" #include "cm-regbits-24xx.h"
#include "cm-regbits-34xx.h" #include "cm-regbits-34xx.h"
@ -61,9 +63,8 @@ int omap2_cm_wait_module_ready(s16 prcm_mod, u8 idlest_id, u8 idlest_shift)
mask = 1 << idlest_shift; mask = 1 << idlest_shift;
/* XXX should be OMAP2 CM */ /* XXX should be OMAP2 CM */
while (((cm_read_mod_reg(prcm_mod, cm_idlest_reg) & mask) != ena) && omap_test_timeout(((cm_read_mod_reg(prcm_mod, cm_idlest_reg) & mask) == ena),
(i++ < MAX_MODULE_READY_TIME)) MAX_MODULE_READY_TIME, i);
udelay(1);
return (i < MAX_MODULE_READY_TIME) ? 0 : -EBUSY; return (i < MAX_MODULE_READY_TIME) ? 0 : -EBUSY;
} }

13
arch/arm/mach-omap2/omap_hwmod.c
View File

@ -45,6 +45,7 @@
#include <linux/mutex.h> #include <linux/mutex.h>
#include <linux/bootmem.h> #include <linux/bootmem.h>
#include <plat/common.h>
#include <plat/cpu.h> #include <plat/cpu.h>
#include <plat/clockdomain.h> #include <plat/clockdomain.h>
#include <plat/powerdomain.h> #include <plat/powerdomain.h>
@ -736,7 +737,7 @@ static int _wait_target_ready(struct omap_hwmod *oh)
static int _reset(struct omap_hwmod *oh) static int _reset(struct omap_hwmod *oh)
{ {
u32 r, v; u32 r, v;
int c; int c = 0;
if (!oh->sysconfig || if (!oh->sysconfig ||
!(oh->sysconfig->sysc_flags & SYSC_HAS_SOFTRESET) || !(oh->sysconfig->sysc_flags & SYSC_HAS_SOFTRESET) ||
@ -758,13 +759,9 @@ static int _reset(struct omap_hwmod *oh)
return r; return r;
_write_sysconfig(v, oh); _write_sysconfig(v, oh);
c = 0; omap_test_timeout((omap_hwmod_readl(oh, oh->sysconfig->syss_offs) &
while (c < MAX_MODULE_RESET_WAIT && SYSS_RESETDONE_MASK),
!(omap_hwmod_readl(oh, oh->sysconfig->syss_offs) & MAX_MODULE_RESET_WAIT, c);
SYSS_RESETDONE_MASK)) {
udelay(1);
c++;
}
if (c == MAX_MODULE_RESET_WAIT) if (c == MAX_MODULE_RESET_WAIT)
WARN(1, "omap_hwmod: %s: failed to reset in %d usec\n", WARN(1, "omap_hwmod: %s: failed to reset in %d usec\n",

5
arch/arm/mach-omap2/prcm.c
View File

@ -241,9 +241,8 @@ int omap2_cm_wait_idlest(void __iomem *reg, u32 mask, const char *name)
BUG(); BUG();
/* Wait for lock */ /* Wait for lock */
while (((__raw_readl(reg) & mask) != ena) && omap_test_timeout(((__raw_readl(reg) & mask) == ena),
(i++ < MAX_MODULE_ENABLE_WAIT)) MAX_MODULE_ENABLE_WAIT, i);
udelay(1);
if (i < MAX_MODULE_ENABLE_WAIT) if (i < MAX_MODULE_ENABLE_WAIT)
pr_debug("cm: Module associated with clock %s ready after %d " pr_debug("cm: Module associated with clock %s ready after %d "

20
arch/arm/plat-omap/include/plat/common.h
View File

@ -71,4 +71,24 @@ void omap2_set_globals_sdrc(struct omap_globals *);
void omap2_set_globals_control(struct omap_globals *); void omap2_set_globals_control(struct omap_globals *);
void omap2_set_globals_prcm(struct omap_globals *); void omap2_set_globals_prcm(struct omap_globals *);
/**
* omap_test_timeout - busy-loop, testing a condition
* @cond: condition to test until it evaluates to true
* @timeout: maximum number of microseconds in the timeout
* @index: loop index (integer)
*
* Loop waiting for @cond to become true or until at least @timeout
* microseconds have passed. To use, define some integer @index in the
* calling code. After running, if @index == @timeout, then the loop has
* timed out.
*/
#define omap_test_timeout(cond, timeout, index) \
({ \
for (index = 0; index < timeout; index++) { \
if (cond) \
break; \
udelay(1); \
} \
})
#endif /* __ARCH_ARM_MACH_OMAP_COMMON_H */ #endif /* __ARCH_ARM_MACH_OMAP_COMMON_H */