MIPS: Enable L2 prefetching for CM >= 2.5
On systems with CM 2.5 & beyond there may be L2 prefetch units present
which are not enabled by default. Detect them, configuring & enabling
prefetching when available.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: linux-kernel@vger.kernel.org
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/11180/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/mm/sc-mips.c b/arch/mips/mm/sc-mips.c
index 1755187..3bd0597 100644
--- a/arch/mips/mm/sc-mips.c
+++ b/arch/mips/mm/sc-mips.c
@@ -51,11 +51,69 @@
/* L2 cache is permanently enabled */
}
+static void mips_sc_prefetch_enable(void)
+{
+ unsigned long pftctl;
+
+ if (mips_cm_revision() < CM_REV_CM2_5)
+ return;
+
+ /*
+ * If there is one or more L2 prefetch unit present then enable
+ * prefetching for both code & data, for all ports.
+ */
+ pftctl = read_gcr_l2_pft_control();
+ if (pftctl & CM_GCR_L2_PFT_CONTROL_NPFT_MSK) {
+ pftctl &= ~CM_GCR_L2_PFT_CONTROL_PAGEMASK_MSK;
+ pftctl |= PAGE_MASK & CM_GCR_L2_PFT_CONTROL_PAGEMASK_MSK;
+ pftctl |= CM_GCR_L2_PFT_CONTROL_PFTEN_MSK;
+ write_gcr_l2_pft_control(pftctl);
+
+ pftctl = read_gcr_l2_pft_control_b();
+ pftctl |= CM_GCR_L2_PFT_CONTROL_B_PORTID_MSK;
+ pftctl |= CM_GCR_L2_PFT_CONTROL_B_CEN_MSK;
+ write_gcr_l2_pft_control_b(pftctl);
+ }
+}
+
+static void mips_sc_prefetch_disable(void)
+{
+ unsigned long pftctl;
+
+ if (mips_cm_revision() < CM_REV_CM2_5)
+ return;
+
+ pftctl = read_gcr_l2_pft_control();
+ pftctl &= ~CM_GCR_L2_PFT_CONTROL_PFTEN_MSK;
+ write_gcr_l2_pft_control(pftctl);
+
+ pftctl = read_gcr_l2_pft_control_b();
+ pftctl &= ~CM_GCR_L2_PFT_CONTROL_B_PORTID_MSK;
+ pftctl &= ~CM_GCR_L2_PFT_CONTROL_B_CEN_MSK;
+ write_gcr_l2_pft_control_b(pftctl);
+}
+
+static bool mips_sc_prefetch_is_enabled(void)
+{
+ unsigned long pftctl;
+
+ if (mips_cm_revision() < CM_REV_CM2_5)
+ return false;
+
+ pftctl = read_gcr_l2_pft_control();
+ if (!(pftctl & CM_GCR_L2_PFT_CONTROL_NPFT_MSK))
+ return false;
+ return !!(pftctl & CM_GCR_L2_PFT_CONTROL_PFTEN_MSK);
+}
+
static struct bcache_ops mips_sc_ops = {
.bc_enable = mips_sc_enable,
.bc_disable = mips_sc_disable,
.bc_wback_inv = mips_sc_wback_inv,
- .bc_inv = mips_sc_inv
+ .bc_inv = mips_sc_inv,
+ .bc_prefetch_enable = mips_sc_prefetch_enable,
+ .bc_prefetch_disable = mips_sc_prefetch_disable,
+ .bc_prefetch_is_enabled = mips_sc_prefetch_is_enabled,
};
/*
@@ -186,6 +244,7 @@
int found = mips_sc_probe();
if (found) {
mips_sc_enable();
+ mips_sc_prefetch_enable();
bcops = &mips_sc_ops;
}
return found;