diff options
Diffstat (limited to 'drivers/ssbi/ssbi.c')
| -rw-r--r-- | drivers/ssbi/ssbi.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/drivers/ssbi/ssbi.c b/drivers/ssbi/ssbi.c index 6fbcb25907f..7ae892590c7 100644 --- a/drivers/ssbi/ssbi.c +++ b/drivers/ssbi/ssbi.c @@ -87,6 +87,15 @@ static inline void ssbi_writel(struct msm_ssbi *ssbi, u32 val, u32 reg) writel(val, ssbi->base + reg); } +/* + * Via private exchange with one of the original authors, the hardware + * should generally finish a transaction in about 5us. The worst + * case, is when using the arbiter and both other CPUs have just + * started trying to use the SSBI bus will result in a time of about + * 20us. It should never take longer than this. + * + * As such, this wait merely spins, with a udelay. + */ static int ssbi_wait_mask(struct msm_ssbi *ssbi, u32 set_mask, u32 clr_mask) { u32 timeout = SSBI_TIMEOUT_US; @@ -161,6 +170,10 @@ err: return ret; } +/* + * See ssbi_wait_mask for an explanation of the time and the + * busywait. + */ static inline int msm_ssbi_pa_transfer(struct msm_ssbi *ssbi, u32 cmd, u8 *data) { |