Re: [PATCH V2 12/16] drm/radeon: Make radeon card usable for Loongson.

From: "j.glisse" <j.glisse@gmail.com>
To: Lucas Stach <dev@lynxeye.de>
Cc: Huacai Chen <chenhuacai@gmail.com>,
	linux-mips@linux-mips.org, Zhangjin Wu <wuzhangjin@gmail.com>,
	Hua Yan <yanh@lemote.com>,
	dri-devel@lists.freedesktop.org,
	Ralf Baechle <ralf@linux-mips.org>,
	Fuxin Zhang <zhangfx@lemote.com>, Huacai Chen <chenhc@lemote.com>,
	Hongliang Tao <taohl@lemote.com>
Subject: Re: [PATCH V2 12/16] drm/radeon: Make radeon card usable for Loongson.
Date: Tue, 19 Jun 2012 10:07:04 -0400	[thread overview]
Message-ID: <20120619140703.GB1979@gmail.com> (raw)
In-Reply-To: <1340090395.8334.7.camel@tellur>

On Tue, Jun 19, 2012 at 09:19:55AM +0200, Lucas Stach wrote:
> Hello Huacai,
> 
> Am Dienstag, den 19.06.2012, 14:50 +0800 schrieb Huacai Chen:
> > 1, Use 32-bit DMA as a workaround (Loongson has a hardware bug that it
> >    doesn't support DMA address above 4GB).
> 
> This is a bug of your platform/CPU and should be fixed at a lower level,
> not in every driver. While radeon might be the only device using 40bit
> DMA right know, it is very well possible that other devices pop up in
> the future. So please fix your platform code to disallow >32bit DMA.
> 
> > 2, Read vga bios offered by system firmware.
> > 3, Handle io prot correctly for MIPS.
> 
> This seems good to me, but you should really split this out in a
> separate TTM patch.
> 
> > 4, Don't use swiotlb on Loongson machines (when use swiotlb, GPU reset
> >    occurs at resume from suspend).
> > 
> While SWIOTLB might not be a common setup, simply ignoring it because it
> doesn't work on your platform is the wrong thing to do. Could you please
> try to root-cause the issue?
> 
> Thanks,
> Lucas

It's most likely because somehow with loongson and swiotlb you get bounce
page, radeon won't work with bounce pages.

Cheers,
Jerome

> 
> > Signed-off-by: Huacai Chen <chenhc@lemote.com>
> > Signed-off-by: Hongliang Tao <taohl@lemote.com>
> > Signed-off-by: Hua Yan <yanh@lemote.com>
> > Cc: dri-devel@lists.freedesktop.org
> > ---
> >  drivers/gpu/drm/drm_vm.c               |    2 +-
> >  drivers/gpu/drm/radeon/radeon_bios.c   |   32 ++++++++++++++++++++++++++++++++
> >  drivers/gpu/drm/radeon/radeon_device.c |    5 +++++
> >  drivers/gpu/drm/radeon/radeon_ttm.c    |    6 +++---
> >  drivers/gpu/drm/ttm/ttm_bo_util.c      |    2 +-
> >  include/drm/drm_sarea.h                |    2 ++
> >  6 files changed, 44 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/drm_vm.c b/drivers/gpu/drm/drm_vm.c
> > index 961ee08..3f06166 100644
> > --- a/drivers/gpu/drm/drm_vm.c
> > +++ b/drivers/gpu/drm/drm_vm.c
> > @@ -62,7 +62,7 @@ static pgprot_t drm_io_prot(uint32_t map_type, struct vm_area_struct *vma)
> >  		tmp = pgprot_writecombine(tmp);
> >  	else
> >  		tmp = pgprot_noncached(tmp);
> > -#elif defined(__sparc__) || defined(__arm__)
> > +#elif defined(__sparc__) || defined(__arm__) || defined(__mips__)
> >  	tmp = pgprot_noncached(tmp);
> >  #endif
> >  	return tmp;
> > diff --git a/drivers/gpu/drm/radeon/radeon_bios.c b/drivers/gpu/drm/radeon/radeon_bios.c
> > index 501f488..2630e22 100644
> > --- a/drivers/gpu/drm/radeon/radeon_bios.c
> > +++ b/drivers/gpu/drm/radeon/radeon_bios.c
> > @@ -29,6 +29,7 @@
> >  #include "radeon_reg.h"
> >  #include "radeon.h"
> >  #include "atom.h"
> > +#include <asm/bootinfo.h>
> >  
> >  #include <linux/vga_switcheroo.h>
> >  #include <linux/slab.h>
> > @@ -73,6 +74,32 @@ static bool igp_read_bios_from_vram(struct radeon_device *rdev)
> >  	return true;
> >  }
> >  
> > +#ifdef CONFIG_CPU_LOONGSON3
> > +extern u64 vgabios_addr;
> > +static bool loongson3_read_bios(struct radeon_device *rdev)
> > +{
> > +	u8 *bios;
> > +	resource_size_t size = 512 * 1024; /* ??? */
> > +
> > +	rdev->bios = NULL;
> > +
> > +	bios = (u8 *)vgabios_addr;
> > +	if (!bios) {
> > +		return false;
> > +	}
> > +
> > +	if (size == 0 || bios[0] != 0x55 || bios[1] != 0xaa) {
> > +		return false;
> > +	}
> > +	rdev->bios = kmalloc(size, GFP_KERNEL);
> > +	if (rdev->bios == NULL) {
> > +		return false;
> > +	}
> > +	memcpy(rdev->bios, bios, size);
> > +	return true;
> > +}
> > +#endif
> > +
> >  static bool radeon_read_bios(struct radeon_device *rdev)
> >  {
> >  	uint8_t __iomem *bios;
> > @@ -490,6 +517,11 @@ bool radeon_get_bios(struct radeon_device *rdev)
> >  	if (r == false) {
> >  		r = radeon_read_disabled_bios(rdev);
> >  	}
> > +#ifdef CONFIG_CPU_LOONGSON3
> > +	if (r == false) {
> > +		r = loongson3_read_bios(rdev);
> > +	}
> > +#endif
> >  	if (r == false || rdev->bios == NULL) {
> >  		DRM_ERROR("Unable to locate a BIOS ROM\n");
> >  		rdev->bios = NULL;
> > diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
> > index 066c98b..8aac7ab 100644
> > --- a/drivers/gpu/drm/radeon/radeon_device.c
> > +++ b/drivers/gpu/drm/radeon/radeon_device.c
> > @@ -777,6 +777,11 @@ int radeon_device_init(struct radeon_device *rdev,
> >  	    (rdev->family < CHIP_RS400))
> >  		rdev->need_dma32 = true;
> >  
> > +#ifdef CONFIG_CPU_LOONGSON3
> > +	/* Workaround: Loongson 3 doesn't support 40-bits DMA */
> > +	rdev->need_dma32 = true;
> > +#endif
> > +
> >  	dma_bits = rdev->need_dma32 ? 32 : 40;
> >  	r = pci_set_dma_mask(rdev->pdev, DMA_BIT_MASK(dma_bits));
> >  	if (r) {
> > diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c
> > index c94a225..f49bdd1 100644
> > --- a/drivers/gpu/drm/radeon/radeon_ttm.c
> > +++ b/drivers/gpu/drm/radeon/radeon_ttm.c
> > @@ -630,7 +630,7 @@ static int radeon_ttm_tt_populate(struct ttm_tt *ttm)
> >  	}
> >  #endif
> >  
> > -#ifdef CONFIG_SWIOTLB
> > +#if defined(CONFIG_SWIOTLB) && !defined(CONFIG_CPU_LOONGSON3)
> >  	if (swiotlb_nr_tbl()) {
> >  		return ttm_dma_populate(&gtt->ttm, rdev->dev);
> >  	}
> > @@ -676,7 +676,7 @@ static void radeon_ttm_tt_unpopulate(struct ttm_tt *ttm)
> >  	}
> >  #endif
> >  
> > -#ifdef CONFIG_SWIOTLB
> > +#if defined(CONFIG_SWIOTLB) && !defined(CONFIG_CPU_LOONGSON3)
> >  	if (swiotlb_nr_tbl()) {
> >  		ttm_dma_unpopulate(&gtt->ttm, rdev->dev);
> >  		return;
> > @@ -906,7 +906,7 @@ static int radeon_ttm_debugfs_init(struct radeon_device *rdev)
> >  	radeon_mem_types_list[i].show = &ttm_page_alloc_debugfs;
> >  	radeon_mem_types_list[i].driver_features = 0;
> >  	radeon_mem_types_list[i++].data = NULL;
> > -#ifdef CONFIG_SWIOTLB
> > +#if defined(CONFIG_SWIOTLB) && !defined(CONFIG_CPU_LOONGSON3)
> >  	if (swiotlb_nr_tbl()) {
> >  		sprintf(radeon_mem_types_names[i], "ttm_dma_page_pool");
> >  		radeon_mem_types_list[i].name = radeon_mem_types_names[i];
> > diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
> > index f8187ea..0df71ea 100644
> > --- a/drivers/gpu/drm/ttm/ttm_bo_util.c
> > +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
> > @@ -472,7 +472,7 @@ pgprot_t ttm_io_prot(uint32_t caching_flags, pgprot_t tmp)
> >  	else
> >  		tmp = pgprot_noncached(tmp);
> >  #endif
> > -#if defined(__sparc__)
> > +#if defined(__sparc__) || defined(__mips__)
> >  	if (!(caching_flags & TTM_PL_FLAG_CACHED))
> >  		tmp = pgprot_noncached(tmp);
> >  #endif
> > diff --git a/include/drm/drm_sarea.h b/include/drm/drm_sarea.h
> > index ee5389d..1d1a858 100644
> > --- a/include/drm/drm_sarea.h
> > +++ b/include/drm/drm_sarea.h
> > @@ -37,6 +37,8 @@
> >  /* SAREA area needs to be at least a page */
> >  #if defined(__alpha__)
> >  #define SAREA_MAX                       0x2000U
> > +#elif defined(__mips__)
> > +#define SAREA_MAX                       0x4000U
> >  #elif defined(__ia64__)
> >  #define SAREA_MAX                       0x10000U	/* 64kB */
> >  #else
> 
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel