Add openbsd,dma-constraint property to /chosen node on armv7

On the Zynq-7000, the DMA constraint has to be adjusted because many
bus masters are unable to access the lowest part of RAM.

OK patrick@ kettenis@

3 files changed, 33 insertions, 4 deletions

diff --git a/sys/arch/armv7/armv7/armv7_machdep.c b/sys/arch/armv7/armv7/armv7_machdep.c
index 804167188c4..b33e3f21fc3 100644
--- a/sys/arch/armv7/armv7/armv7_machdep.c
+++ b/sys/arch/armv7/armv7/armv7_machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: armv7_machdep.c,v 1.63 2021/03/25 04:12:01 jsg Exp $ */
+/*	$OpenBSD: armv7_machdep.c,v 1.64 2021/10/06 12:50:10 visa Exp $ */
 /*	$NetBSD: lubbock_machdep.c,v 1.2 2003/07/15 00:25:06 lukem Exp $ */
 
 /*
@@ -453,6 +453,12 @@ initarm(void *arg0, void *arg1, void *arg2, paddr_t loadaddr)
 		len = fdt_node_property(node, "openbsd,uefi-mmap-desc-ver", &prop);
 		if (len == sizeof(mmap_desc_ver))
 			mmap_desc_ver = bemtoh32((uint32_t *)prop);
+
+		len = fdt_node_property(node, "openbsd,dma-constraint", &prop);
+		if (len == sizeof(uint64_t[2])) {
+			dma_constraint.ucr_low = bemtoh64((uint64_t *)prop);
+			dma_constraint.ucr_high = bemtoh64((uint64_t *)prop + 1);
+		}
 	}
 
 	process_kernel_args();
diff --git a/sys/arch/armv7/stand/efiboot/conf.c b/sys/arch/armv7/stand/efiboot/conf.c
index bc093179811..9968136184a 100644
--- a/sys/arch/armv7/stand/efiboot/conf.c
+++ b/sys/arch/armv7/stand/efiboot/conf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: conf.c,v 1.31 2021/06/10 22:17:58 krw Exp $	*/
+/*	$OpenBSD: conf.c,v 1.32 2021/10/06 12:50:10 visa Exp $	*/
 
 /*
  * Copyright (c) 1996 Michael Shalayeff
@@ -42,7 +42,7 @@
 #include "efidev.h"
 #include "efipxe.h"
 
-const char version[] = "1.18";
+const char version[] = "1.19";
 int	debug = 0;
 
 struct fs_ops file_system[] = {
diff --git a/sys/arch/armv7/stand/efiboot/efiboot.c b/sys/arch/armv7/stand/efiboot/efiboot.c
index 2e452ff6b94..588e1c99b10 100644
--- a/sys/arch/armv7/stand/efiboot/efiboot.c
+++ b/sys/arch/armv7/stand/efiboot/efiboot.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: efiboot.c,v 1.34 2021/06/07 21:18:31 krw Exp $	*/
+/*	$OpenBSD: efiboot.c,v 1.35 2021/10/06 12:50:10 visa Exp $	*/
 
 /*
  * Copyright (c) 2015 YASUOKA Masahiko <yasuoka@yasuoka.net>
@@ -435,6 +435,28 @@ efi_framebuffer(void)
 	    sizeof(framebuffer_path));
 }
 
+uint64_t dma_constraint[2] = { 0, -1 };
+
+void
+efi_dma_constraint(void)
+{
+	void *node;
+
+	/* Raspberry Pi 4 is "special". */
+	node = fdt_find_node("/");
+	if (fdt_node_is_compatible(node, "brcm,bcm2711"))
+		dma_constraint[1] = htobe64(0x3bffffff);
+
+	/* Not all bus masters can access 0x0-0x7ffff on Zynq-7000. */
+	if (fdt_node_is_compatible(node, "xlnx,zynq-7000"))
+		dma_constraint[0] = htobe64(0x00080000);
+
+	/* Pass DMA constraint. */
+	node = fdt_find_node("/chosen");
+	fdt_node_add_property(node, "openbsd,dma-constraint",
+	    dma_constraint, sizeof(dma_constraint));
+}
+
 void
 efi_console(void)
 {
@@ -515,6 +537,7 @@ efi_makebootargs(char *bootargs, int howto)
 
 	efi_framebuffer();
 	efi_console();
+	efi_dma_constraint();
 
 	fdt_finalize();