[U-Boot] [PATCH] video: bcm2835: use bus_to_phys() on FB address

[U-Boot] [PATCH] video: bcm2835: use bus_to_phys() on FB address

[Stephen Warren]

The FB address is generated by the firmware running on the GPU/VideoCore
and is a "bus" address. This address is the other side of an IOMMU from
the ARM upon which U-Boot is running. Use bus_to_phys() to convert this
to an ARM physical address. Without this, U-Boot seems to work just fine,
but once the Linux kernel boots on an RPi2, accessing the FB memory often
causes a hard system hang.

This is related to:
122426d46e31 ARM: bcm2835: use phys_to_bus() for mbox
5c0beb5c58c8 usb: dwc2: use phys_to_bus/bus_to_phys
79340db7f1f6 ARM: bcm2835: implement phys_to_bus/bus_to_phys

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
---
 drivers/video/bcm2835.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/video/bcm2835.c b/drivers/video/bcm2835.c
index 7867fe3895d0..bff1fcb9eaf7 100644
--- a/drivers/video/bcm2835.c
+++ b/drivers/video/bcm2835.c
@@ -7,6 +7,7 @@
 #include <common.h>
 #include <lcd.h>
 #include <memalign.h>
+#include <phys2bus.h>
 #include <asm/arch/mbox.h>
 #include <asm/global_data.h>
 
@@ -103,7 +104,8 @@ void lcd_ctrl_init(void *lcdbase)
 	panel_info.vl_row = h;
 	panel_info.vl_bpix = LCD_COLOR16;
 
-	gd->fb_base = msg_setup->allocate_buffer.body.resp.fb_address;
+	gd->fb_base = bus_to_phys(
+		msg_setup->allocate_buffer.body.resp.fb_address);
 }
 
 void lcd_enable(void)
-- 
1.9.1

[U-Boot] [PATCH] video: bcm2835: use bus_to_phys() on FB address

[Anatolij Gustschin]

Hi Stephen,

On Sat,  6 Feb 2016 10:42:43 -0700
Stephen Warren swarren at wwwdotorg.org wrote:

> The FB address is generated by the firmware running on the GPU/VideoCore
> and is a "bus" address. This address is the other side of an IOMMU from
> the ARM upon which U-Boot is running. Use bus_to_phys() to convert this
> to an ARM physical address. Without this, U-Boot seems to work just fine,
> but once the Linux kernel boots on an RPi2, accessing the FB memory often
> causes a hard system hang.
> 
> This is related to:
> 122426d46e31 ARM: bcm2835: use phys_to_bus() for mbox
> 5c0beb5c58c8 usb: dwc2: use phys_to_bus/bus_to_phys
> 79340db7f1f6 ARM: bcm2835: implement phys_to_bus/bus_to_phys
> 
> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
> ---
>  drivers/video/bcm2835.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)

applied to u-boot-video/master, thanks!

--
Anatolij