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| author | Ambresh K <ambresh@ti.com> | 2011-10-03 18:45:16 -0700 |
|---|---|---|
| committer | Todd Poynor <toddpoynor@google.com> | 2011-10-06 19:09:25 -0700 |
| commit | 9aba00ea6a83e8055534c3d83831adc22576c824 (patch) | |
| tree | 0147857c2ef5880eb47c082a705b98c95fe42eee /drivers/omap_hsi | |
| parent | fba74cafd7522984373612f74048ca474316c830 (diff) | |
| download | kernel_samsung_tuna-9aba00ea6a83e8055534c3d83831adc22576c824.zip kernel_samsung_tuna-9aba00ea6a83e8055534c3d83831adc22576c824.tar.gz kernel_samsung_tuna-9aba00ea6a83e8055534c3d83831adc22576c824.tar.bz2 | |
OMAP4: HSI: PM: Errata: DSP woken-up by HSI CAWAKE signal
Description:
There is a silicon bug in HSI IP.
The logic for generating the SWakeup for DSP is same as the logic for generating
SWakeup for MPU, even when DSP interrupt generation is disabled.
As a result when the MPU Wakeup is generated, a false DSP wakeup is also
generated.
Consequences of this bug in below scenario:
- Modem interface (HSI is enabled)
- The system is allowed to suspend
- When CAWAKE signal has activity, it will wake-up MPU; it also wakes up
DSP incorrectly
- The DSP is not able to handle this wake up correctly.
- Next suspend, system can’t enter in off-mode because DSP remains
active
This errata needs to be handled in two scenarios:
a) If the device has woken-up from RET/OFF through CAWAKE signal and is taken
care as part of wakeup from suspend.
b) During MPU active and HSI transitioning from its internal low power state,
will generate SWakeup signal which eventually wakeup's DSP. This prevents
DSP (Tesla) from entering low power state and thus handling this corner case
in HSI interrupt handler as recommended by silicon team.
Signed-off-by: Vinay Chaurasia <vinayc@ti.com>
Signed-off-by: Ambresh K <ambresh@ti.com>
Diffstat (limited to 'drivers/omap_hsi')
| -rw-r--r-- | drivers/omap_hsi/hsi_driver.h | 11 | ||||
| -rw-r--r-- | drivers/omap_hsi/hsi_driver_int.c | 9 |
2 files changed, 20 insertions, 0 deletions
diff --git a/drivers/omap_hsi/hsi_driver.h b/drivers/omap_hsi/hsi_driver.h index ab642b1..027f3ca 100644 --- a/drivers/omap_hsi/hsi_driver.h +++ b/drivers/omap_hsi/hsi_driver.h @@ -405,4 +405,15 @@ static inline int hsi_clocks_enable(struct device *dev, const char *s) return hsi_clocks_enable_channel(dev, HSI_CH_NUMBER_NONE, s); } +#if defined(CONFIG_PM) && defined(CONFIG_ARCH_OMAP4) +extern u8 pm44xx_errata; +#define IS_HSI_PM44XX_ERRATUM(id) (pm44xx_errata & (id)) +#define OMAP4_PM_ERRATUM_HSI_SWAKEUP_iXXX BIT(2) +extern void omap_pm_clear_dsp_wake_up(void); +#else +#define IS_HSI_PM44XX_ERRATUM(id) 0 +#define OMAP4_PM_ERRATUM_HSI_SWAKEUP_iXXX 0 +#define static inline void omap_pm_clear_dsp_wake_up(void) { } +#endif + #endif /* __HSI_DRIVER_H__ */ diff --git a/drivers/omap_hsi/hsi_driver_int.c b/drivers/omap_hsi/hsi_driver_int.c index f93725b..8389782 100644 --- a/drivers/omap_hsi/hsi_driver_int.c +++ b/drivers/omap_hsi/hsi_driver_int.c @@ -455,6 +455,15 @@ int hsi_do_cawake_process(struct hsi_port *pport) spin_unlock(&hsi_ctrl->lock); hsi_port_event_handler(pport, HSI_EVENT_CAWAKE_UP, NULL); spin_lock(&hsi_ctrl->lock); + + /* + * HSI - OMAP4430-2.2BUG00055: + * HSI: DSP Swakeup generated is the same than MPU Swakeup. + * System can’t enter in off mode due to the DSP. + */ + if (IS_HSI_PM44XX_ERRATUM(OMAP4_PM_ERRATUM_HSI_SWAKEUP_iXXX)) + omap_pm_clear_dsp_wake_up(); + } else { dev_dbg(hsi_ctrl->dev, "CAWAKE falling edge detected\n"); |