[PATCH v2 04/12] MIPS: pm-cps: Update comments on barrier instructions

[Matt Redfearn]

This code makes large use of barriers, which had quite vague
descriptions. Update the comments to make the choice of barrier and
reason for it more clear.

Signed-off-by: Matt Redfearn <matt.redfe...@imgtec.com>
Reviewed-by: Paul Burton <paul.bur...@imgtec.com>

---

Changes in v2:
Update comments on barriers

 arch/mips/kernel/pm-cps.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/mips/kernel/pm-cps.c b/arch/mips/kernel/pm-cps.c
index 2faa227a032e..7e8d4aa22233 100644
--- a/arch/mips/kernel/pm-cps.c
+++ b/arch/mips/kernel/pm-cps.c
@@ -315,7 +315,7 @@ static int __init cps_gen_flush_fsb(u32 **pp, struct 
uasm_label **pl,
                             i * line_size * line_stride, t0);
        }
 
-       /* Completion barrier */
+       /* Barrier ensuring previous cache invalidates are complete */
        uasm_i_sync(pp, stype_memory);
        uasm_i_ehb(pp);
 
@@ -414,7 +414,7 @@ static void * __init cps_gen_entry_code(unsigned cpu, enum 
cps_pm_state state)
                uasm_il_beqz(&p, &r, t2, lbl_incready);
                uasm_i_addiu(&p, t1, t1, 1);
 
-               /* Ordering barrier */
+               /* Barrier ensuring all CPUs see the updated r_nc_count value */
                uasm_i_sync(&p, stype_ordering);
 
                /*
@@ -467,7 +467,7 @@ static void * __init cps_gen_entry_code(unsigned cpu, enum 
cps_pm_state state)
        cps_gen_cache_routine(&p, &l, &r, &cpu_data[cpu].dcache,
                              Index_Writeback_Inv_D, lbl_flushdcache);
 
-       /* Completion barrier */
+       /* Barrier ensuring previous cache invalidates are complete */
        uasm_i_sync(&p, stype_memory);
        uasm_i_ehb(&p);
 
@@ -480,7 +480,7 @@ static void * __init cps_gen_entry_code(unsigned cpu, enum 
cps_pm_state state)
        uasm_i_sw(&p, t0, 0, r_pcohctl);
        uasm_i_lw(&p, t0, 0, r_pcohctl);
 
-       /* Sync to ensure previous interventions are complete */
+       /* Barrier to ensure write to coherence control is complete */
        uasm_i_sync(&p, stype_intervention);
        uasm_i_ehb(&p);
 
@@ -526,7 +526,7 @@ static void * __init cps_gen_entry_code(unsigned cpu, enum 
cps_pm_state state)
                        goto gen_done;
                }
 
-               /* Completion barrier */
+               /* Barrier to ensure write to CPC command is complete */
                uasm_i_sync(&p, stype_memory);
                uasm_i_ehb(&p);
        }
@@ -561,7 +561,7 @@ static void * __init cps_gen_entry_code(unsigned cpu, enum 
cps_pm_state state)
        uasm_i_sw(&p, t0, 0, r_pcohctl);
        uasm_i_lw(&p, t0, 0, r_pcohctl);
 
-       /* Completion barrier */
+       /* Barrier to ensure write to coherence control is complete */
        uasm_i_sync(&p, stype_memory);
        uasm_i_ehb(&p);
 
@@ -575,7 +575,7 @@ static void * __init cps_gen_entry_code(unsigned cpu, enum 
cps_pm_state state)
                uasm_il_beqz(&p, &r, t2, lbl_decready);
                uasm_i_andi(&p, v0, t1, (1 << fls(smp_num_siblings)) - 1);
 
-               /* Ordering barrier */
+               /* Barrier ensuring all CPUs see the updated r_nc_count value */
                uasm_i_sync(&p, stype_ordering);
        }
 
@@ -597,7 +597,7 @@ static void * __init cps_gen_entry_code(unsigned cpu, enum 
cps_pm_state state)
                 */
                uasm_build_label(&l, p, lbl_secondary_cont);
 
-               /* Ordering barrier */
+               /* Barrier ensuring all CPUs see the updated r_nc_count value */
                uasm_i_sync(&p, stype_ordering);
        }
 
-- 
2.7.4