mips: Implement basic pmap_kenter_device, pmap_kremove_device

Unbreak mips.BERI_DE4_SDROOT build, which uses device xdma. Device xdma
depends on the pmap_kenter_device APIs.

Reported by:	tinderbox (local)
Sponsored by:	Dell EMC Isilon

2 files changed, 40 insertions, 0 deletions

diff --git a/sys/mips/include/pmap.h b/sys/mips/include/pmap.h
index ba31de835d23..edc9089a6fbc 100644
--- a/sys/mips/include/pmap.h
+++ b/sys/mips/include/pmap.h
@@ -177,7 +177,9 @@ void pmap_unmapdev(vm_offset_t, vm_size_t);
 vm_offset_t pmap_steal_memory(vm_size_t size);
 void pmap_kenter(vm_offset_t va, vm_paddr_t pa);
 void pmap_kenter_attr(vm_offset_t va, vm_paddr_t pa, vm_memattr_t attr);
+void pmap_kenter_device(vm_offset_t, vm_size_t, vm_paddr_t);
 void pmap_kremove(vm_offset_t va);
+void pmap_kremove_device(vm_offset_t, vm_size_t);
 void *pmap_kenter_temporary(vm_paddr_t pa, int i);
 void pmap_kenter_temporary_free(vm_paddr_t pa);
 void pmap_flush_pvcache(vm_page_t m);
diff --git a/sys/mips/mips/pmap.c b/sys/mips/mips/pmap.c
index a0de635ff396..d0edad94a582 100644
--- a/sys/mips/mips/pmap.c
+++ b/sys/mips/mips/pmap.c
@@ -854,6 +854,44 @@ pmap_kenter(vm_offset_t va, vm_paddr_t pa)
 	pmap_kenter_attr(va, pa, VM_MEMATTR_DEFAULT);
 }
 
+void
+pmap_kenter_device(vm_offset_t va, vm_size_t size, vm_paddr_t pa)
+{
+
+	KASSERT((size & PAGE_MASK) == 0,
+	    ("%s: device mapping not page-sized", __func__));
+
+	for (; size > 0; size -= PAGE_SIZE) {
+		/*
+		 * XXXCEM: this is somewhat inefficient on SMP systems in that
+		 * every single page is individually TLB-invalidated via
+		 * rendezvous (pmap_update_page()), instead of invalidating the
+		 * entire range via a single rendezvous.
+		 */
+		pmap_kenter_attr(va, pa, VM_MEMATTR_UNCACHEABLE);
+		va += PAGE_SIZE;
+		pa += PAGE_SIZE;
+	}
+}
+
+void
+pmap_kremove_device(vm_offset_t va, vm_size_t size)
+{
+
+	KASSERT((size & PAGE_MASK) == 0,
+	    ("%s: device mapping not page-sized", __func__));
+
+	/*
+	 * XXXCEM: Similar to pmap_kenter_device, this is inefficient on SMP,
+	 * in that pages are invalidated individually instead of a single range
+	 * rendezvous.
+	 */
+	for (; size > 0; size -= PAGE_SIZE) {
+		pmap_kremove(va);
+		va += PAGE_SIZE;
+	}
+}
+
 /*
  * remove a page from the kernel pagetables
  */