Re: [PATCH 21/22] drm/tegra: Don't use IOMMU on Tegra20

On 23.05.2017 03:16, Dmitry Osipenko wrote:

There is no IOMMU on Tegra20, instead a GART would be picked as an IOMMU provider.

Signed-off-by: Dmitry Osipenko digetx@gmail.com

drivers/gpu/drm/tegra/drm.c | 5 ++++- drivers/gpu/host1x/dev.c | 5 ++++- 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c index 17416e1c219a..ac8f76d9475f 100644 --- a/drivers/gpu/drm/tegra/drm.c +++ b/drivers/gpu/drm/tegra/drm.c @@ -15,6 +15,8 @@ #include <drm/drm_atomic.h> #include <drm/drm_atomic_helper.h>

+#include <soc/tegra/fuse.h>

#include "drm.h" #include "gem.h"

@@ -131,7 +133,8 @@ static int tegra_drm_load(struct drm_device *drm, unsigned long flags) if (!tegra) return -ENOMEM;

• if (iommu_present(&platform_bus_type)) {

• if (iommu_present(&platform_bus_type) &&

•    tegra_get_chip_id() != TEGRA20) {
  

  u64 carveout_start, carveout_end, gem_start, gem_end; struct iommu_domain_geometry *geometry; unsigned long order;

diff --git a/drivers/gpu/host1x/dev.c b/drivers/gpu/host1x/dev.c index 5c1c711a21af..56b7e6d51894 100644 --- a/drivers/gpu/host1x/dev.c +++ b/drivers/gpu/host1x/dev.c @@ -25,6 +25,8 @@ #include <linux/of.h> #include <linux/slab.h>

+#include <soc/tegra/fuse.h>

#define CREATE_TRACE_POINTS #include <trace/events/host1x.h> #undef CREATE_TRACE_POINTS @@ -177,7 +179,8 @@ static int host1x_probe(struct platform_device *pdev) return err; }

• if (iommu_present(&platform_bus_type)) {

• if (iommu_present(&platform_bus_type) &&

•    tegra_get_chip_id() != TEGRA20) {
  

  struct iommu_domain_geometry *geometry; unsigned long order;

Nicolas noticed that this breaks driver module compilation, as the `tegra_get_chip_id` is not an exported symbol. I'll consider alternatives to symbol exporting and will fix it in the new revision of the patch.