lib: Remove redundant sbi_platform_ipi_clear() calls

The sbi_platform_ipi_clear() called from wait_for_coldboot() and
sbi_hsm_hart_wait() is redundant because IPI will be automatically
cleared by sbi_platform_ipi_init() called from sbi_ipi_init().

Further, wait_for_coldboot() is common for warm startup and warm
resume path so the sbi_platform_ipi_clear() called in warm resume
path cause resuming HART to miss an IPI injected other HART to
wakeup the HART.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

diff --git a/lib/sbi/sbi_hsm.c b/lib/sbi/sbi_hsm.c
index ace6a9d..bbc4ce9 100644 (file)
--- a/lib/sbi/sbi_hsm.c
+++ b/lib/sbi/sbi_hsm.c
@@ -107,7 +107,6 @@ void sbi_hsm_prepare_next_jump(struct sbi_scratch *scratch, u32 hartid)
 static void sbi_hsm_hart_wait(struct sbi_scratch *scratch, u32 hartid)
 {
        unsigned long saved_mie;
-       const struct sbi_platform *plat = sbi_platform_ptr(scratch);
        struct sbi_hsm_data *hdata = sbi_scratch_offset_ptr(scratch,
                                                            hart_data_offset);
        /* Save MIE CSR */
@@ -124,8 +123,10 @@ static void sbi_hsm_hart_wait(struct sbi_scratch *scratch, u32 hartid)
        /* Restore MIE CSR */
        csr_write(CSR_MIE, saved_mie);
 
-       /* Clear current HART IPI */
-       sbi_platform_ipi_clear(plat, hartid);
+       /*
+        * No need to clear IPI here because the sbi_ipi_init() will
+        * clear it for current HART via sbi_platform_ipi_init().
+        */
 }
 
 int sbi_hsm_init(struct sbi_scratch *scratch, u32 hartid, bool cold_boot)

diff --git a/lib/sbi/sbi_init.c b/lib/sbi/sbi_init.c
index 1d4a838..4de2dfa 100644 (file)
--- a/lib/sbi/sbi_init.c
+++ b/lib/sbi/sbi_init.c
@@ -130,7 +130,6 @@ static unsigned long coldboot_done;
 static void wait_for_coldboot(struct sbi_scratch *scratch, u32 hartid)
 {
        unsigned long saved_mie, cmip;
-       const struct sbi_platform *plat = sbi_platform_ptr(scratch);
 
        /* Save MIE CSR */
        saved_mie = csr_read(CSR_MIE);
@@ -167,8 +166,14 @@ static void wait_for_coldboot(struct sbi_scratch *scratch, u32 hartid)
        /* Restore MIE CSR */
        csr_write(CSR_MIE, saved_mie);
 
-       /* Clear current HART IPI */
-       sbi_platform_ipi_clear(plat, hartid);
+       /*
+        * The wait for coldboot is common for both warm startup and
+        * warm resume path so clearing IPI here would result in losing
+        * an IPI in warm resume path.
+        *
+        * Also, the sbi_platform_ipi_init() called from sbi_ipi_init()
+        * will automatically clear IPI for current HART.
+        */
 }
 
 static void wake_coldboot_harts(struct sbi_scratch *scratch, u32 hartid)

diff --git a/lib/sbi/sbi_ipi.c b/lib/sbi/sbi_ipi.c
index a3a6ce6..b50735e 100644 (file)
--- a/lib/sbi/sbi_ipi.c
+++ b/lib/sbi/sbi_ipi.c
@@ -230,7 +230,10 @@ int sbi_ipi_init(struct sbi_scratch *scratch, bool cold_boot)
        ipi_data = sbi_scratch_offset_ptr(scratch, ipi_data_off);
        ipi_data->ipi_type = 0x00;
 
-       /* Platform init */
+       /*
+        * Initialize platform IPI support. This will also clear any
+        * pending IPIs for current/calling HART.
+        */
        ret = sbi_platform_ipi_init(sbi_platform_ptr(scratch), cold_boot);
        if (ret)
                return ret;