From 2723123cafb705c78b5251329bdd932ca6b834d9 Mon Sep 17 00:00:00 2001
From: kettenis <kettenis@openbsd.org>
Date: Mon, 27 Aug 2018 09:30:07 +0000
Subject: [PATCH] Add an interface that allows drivers to claim a framebuffer
 and check whether another driver has already claimed a framebuffer.  Use this
 in radeondrm(4) and simplefb(4) to prevent the latter from attaching if
 radeondrm(4) is attached to the hardware that provides the framebuffer set up
 by the firmware.

ok mlarkin@
---
 sys/dev/fdt/simplefb.c              |  6 ++++-
 sys/dev/pci/drm/radeon/radeon_kms.c |  5 ++++
 sys/dev/rasops/rasops.c             | 38 ++++++++++++++++++++++++++++-
 sys/dev/rasops/rasops.h             |  4 ++-
 4 files changed, 50 insertions(+), 3 deletions(-)

diff --git a/sys/dev/fdt/simplefb.c b/sys/dev/fdt/simplefb.c
index 3be2ac6d004..6f031953a3c 100644
--- a/sys/dev/fdt/simplefb.c
+++ b/sys/dev/fdt/simplefb.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: simplefb.c,v 1.4 2018/07/31 17:25:55 fcambus Exp $	*/
+/*	$OpenBSD: simplefb.c,v 1.5 2018/08/27 09:30:07 kettenis Exp $	*/
 /*
  * Copyright (c) 2016 Mark Kettenis
  *
@@ -110,6 +110,10 @@ simplefb_match(struct device *parent, void *match, void *aux)
 {
 	struct fdt_attach_args *faa = aux;
 
+	/* Don't attach if another driver already claimed our framebuffer. */
+	if (faa->fa_nreg > 0 && rasops_check_framebuffer(faa->fa_reg[0].addr))
+		return 0;
+
 	return OF_is_compatible(faa->fa_node, "simple-framebuffer");
 }
 
diff --git a/sys/dev/pci/drm/radeon/radeon_kms.c b/sys/dev/pci/drm/radeon/radeon_kms.c
index acc0fbc95cb..f9e72e449cd 100644
--- a/sys/dev/pci/drm/radeon/radeon_kms.c
+++ b/sys/dev/pci/drm/radeon/radeon_kms.c
@@ -435,6 +435,7 @@ radeondrm_attach_kms(struct device *parent, struct device *self, void *aux)
 	pcireg_t		 type;
 	int			 i;
 	uint8_t			 rmmio_bar;
+	paddr_t			 fb_aper;
 #if !defined(__sparc64__)
 	pcireg_t		 addr, mask;
 	int			 s;
@@ -660,6 +661,10 @@ radeondrm_attach_kms(struct device *parent, struct device *self, void *aux)
 }
 #endif
 
+	fb_aper = bus_space_mmap(rdev->memt, rdev->fb_aper_offset, 0, 0, 0);
+	if (fb_aper != -1)
+		rasops_claim_framebuffer(fb_aper, rdev->fb_aper_size, self);
+
 	rdev->shutdown = true;
 	config_mountroot(self, radeondrm_attachhook);
 }
diff --git a/sys/dev/rasops/rasops.c b/sys/dev/rasops/rasops.c
index e483ff074ad..ec2c7bac4ca 100644
--- a/sys/dev/rasops/rasops.c
+++ b/sys/dev/rasops/rasops.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rasops.c,v 1.55 2018/08/25 12:23:45 kettenis Exp $	*/
+/*	$OpenBSD: rasops.c,v 1.56 2018/08/27 09:30:07 kettenis Exp $	*/
 /*	$NetBSD: rasops.c,v 1.35 2001/02/02 06:01:01 marcus Exp $	*/
 
 /*-
@@ -1968,3 +1968,39 @@ rasops_scrollback(void *v, void *cookie, int lines)
 	if (scr->rs_crow != -1 && scr->rs_visibleoffset == scr->rs_dispoffset)
 		rasops_cursor(ri, 1, scr->rs_crow, scr->rs_ccol);
 }
+
+struct rasops_framebuffer {
+	SLIST_ENTRY(rasops_framebuffer)	rf_list;
+	paddr_t		rf_base;
+	psize_t		rf_size;
+	struct device	*rf_dev;
+};
+
+SLIST_HEAD(, rasops_framebuffer) rasops_framebuffers =
+    SLIST_HEAD_INITIALIZER(&rasops_framebuffers);
+
+void
+rasops_claim_framebuffer(paddr_t base, psize_t size, struct device *dev)
+{
+	struct rasops_framebuffer *rf;
+
+	rf = malloc(sizeof(*rf), M_DEVBUF, M_WAITOK);
+	rf->rf_base = base;
+	rf->rf_size = size;
+	rf->rf_dev = dev;
+
+	SLIST_INSERT_HEAD(&rasops_framebuffers, rf, rf_list);
+}
+
+int
+rasops_check_framebuffer(paddr_t base)
+{
+	struct rasops_framebuffer *rf;
+
+	SLIST_FOREACH(rf, &rasops_framebuffers, rf_list) {
+		if (base >= rf->rf_base && base < rf->rf_base + rf->rf_size)
+			return 1;
+	}
+
+	return 0;
+}
diff --git a/sys/dev/rasops/rasops.h b/sys/dev/rasops/rasops.h
index bab120e5309..89de261be89 100644
--- a/sys/dev/rasops/rasops.h
+++ b/sys/dev/rasops/rasops.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rasops.h,v 1.22 2018/04/27 21:36:12 jcs Exp $ */
+/*	$OpenBSD: rasops.h,v 1.23 2018/08/27 09:30:07 kettenis Exp $ */
 /* 	$NetBSD: rasops.h,v 1.13 2000/06/13 13:36:54 ad Exp $ */
 
 /*-
@@ -179,6 +179,8 @@ int	rasops_load_font(void *, void *, struct wsdisplay_font *);
 int	rasops_list_font(void *, struct wsdisplay_font *);
 int	rasops_getchar(void *, int, int, struct wsdisplay_charcell *);
 void	rasops_scrollback(void *, void *, int);
+void	rasops_claim_framebuffer(paddr_t, psize_t, struct device *);
+int	rasops_check_framebuffer(paddr_t);
 
 extern const u_char	rasops_isgray[16];
 extern const u_char	rasops_cmap[256*3];
-- 
2.20.1