@@ -220,8 +220,7 @@ void sbi_ipi_process(void)
u32 hartindex = sbi_hartid_to_hartindex(current_hartid());
sbi_pmu_ctr_incr_fw(SBI_PMU_FW_IPI_RECVD);
- if (ipi_dev && ipi_dev->ipi_clear)
- ipi_dev->ipi_clear(hartindex);
+ sbi_ipi_raw_clear(hartindex);
ipi_type = atomic_raw_xchg_ulong(&ipi_data->ipi_type, 0);
ipi_event = 0;
@@ -247,6 +246,8 @@ int sbi_ipi_raw_send(u32 hartindex)
* or MMIO writes done by the ipi_send() device
* callback. This also allows the ipi_send() device
* callback to use relaxed MMIO writes.
+ *
+ * This pairs with the wmb() in sbi_ipi_raw_clear().
*/
wmb();
@@ -258,6 +259,17 @@ void sbi_ipi_raw_clear(u32 hartindex)
{
if (ipi_dev && ipi_dev->ipi_clear)
ipi_dev->ipi_clear(hartindex);
+
+ /*
+ * Ensure that memory or MMIO writes after this
+ * function returns are not observed before the
+ * memory or MMIO writes done by the ipi_clear()
+ * device callback. This also allows ipi_clear()
+ * device callback to use relaxed MMIO writes.
+ *
+ * This pairs with the wmb() in sbi_ipi_raw_send().
+ */
+ wmb();
}
const struct sbi_ipi_device *sbi_ipi_get_device(void)
@@ -61,7 +61,7 @@ static void mswi_ipi_clear(u32 hart_index)
/* Clear ACLINT IPI */
msip = (void *)mswi->addr;
- writel(0, &msip[sbi_hartindex_to_hartid(hart_index) -
+ writel_relaxed(0, &msip[sbi_hartindex_to_hartid(hart_index) -
mswi->first_hartid]);
}
Currently, there are no barriers before or after the ipi_clear() device callback which forces ipi_clear() device callback to always use non-relaxed MMIO writes. Instead of above, we use wmb() in after the ipi_clear() device callback which pairs with the wmb() done before the ipi_send() device callback. This also allows device ipi_clear() callback to use relaxed MMIO writes. Signed-off-by: Anup Patel <apatel@ventanamicro.com> --- lib/sbi/sbi_ipi.c | 16 ++++++++++++++-- lib/utils/ipi/aclint_mswi.c | 2 +- 2 files changed, 15 insertions(+), 3 deletions(-)