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ARM: OMAP1: create read_reset_sources() function (for initial use by watchdog) 

On OMAP1, the existing OMAP watchdog driver reads a register directly
from a non-watchdog IP block.  It also does not convert the register's
contents into the standard WDIOF_* bits expected from the
GETBOOTSTATUS ioctl().

To move towards fixing these problems, create an function in
arch/arm/mach-omap1 to return the reset source data.  A subsequent
patch will provide this function to the watchdog driver via
platform_data.

In the long term, the best approach would be to move this function
to a new OMAP1 driver that handles access to the OMAP1 Clock
Generation and Reset Management IP block.  Then no platform_data would
be needed.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
This commit is contained in:
Paul Walmsley 2012-10-21 01:01:12 -06:00
parent 21325b25f4
commit b5c5353d41
2 changed files with 40 additions and 0 deletions
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2
arch/arm/mach-omap1/common.h
View File

@ -90,4 +90,6 @@ extern int ocpi_enable(void);
static inline int ocpi_enable(void) { return 0; }
#endif
extern int omap1_get_reset_sources(void);
#endif /* __ARCH_ARM_MACH_OMAP1_COMMON_H */

38
arch/arm/mach-omap1/reset.c
View File

@ -10,6 +10,19 @@
#include "common.h"
/* ARM_SYSST bit shifts related to SoC reset sources */
#define ARM_SYSST_POR_SHIFT 5
#define ARM_SYSST_EXT_RST_SHIFT 4
#define ARM_SYSST_ARM_WDRST_SHIFT 2
#define ARM_SYSST_GLOB_SWRST_SHIFT 1
/* Standardized reset source bits (across all OMAP SoCs) */
#define OMAP_GLOBAL_COLD_RST_SRC_ID_SHIFT 0
#define OMAP_GLOBAL_WARM_RST_SRC_ID_SHIFT 1
#define OMAP_MPU_WD_RST_SRC_ID_SHIFT 3
#define OMAP_EXTWARM_RST_SRC_ID_SHIFT 5
void omap1_restart(char mode, const char *cmd)
{
/*
@ -23,3 +36,28 @@ void omap1_restart(char mode, const char *cmd)
omap_writew(1, ARM_RSTCT1);
}
/**
* omap1_get_reset_sources - return the source of the SoC's last reset
*
* Returns bits that represent the last reset source for the SoC. The
* format is standardized across OMAPs for use by the OMAP watchdog.
*/
int omap1_get_reset_sources(void)
{
int ret = 0;
u16 rs;
rs = __raw_readw(ARM_SYSST);
if (rs & (1 << ARM_SYSST_POR_SHIFT))
ret |= 1 << OMAP_GLOBAL_COLD_RST_SRC_ID_SHIFT;
if (rs & (1 << ARM_SYSST_EXT_RST_SHIFT))
ret |= 1 << OMAP_EXTWARM_RST_SRC_ID_SHIFT;
if (rs & (1 << ARM_SYSST_ARM_WDRST_SHIFT))
ret |= 1 << OMAP_MPU_WD_RST_SRC_ID_SHIFT;
if (rs & (1 << ARM_SYSST_GLOB_SWRST_SHIFT))
ret |= 1 << OMAP_GLOBAL_WARM_RST_SRC_ID_SHIFT;
return ret;
}