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<div class="moz-cite-prefix">Am 19.09.2017 um 13:20 schrieb Tom St
Denis:<br>
</div>
<blockquote type="cite"
cite="mid:20170919112057.24377-1-tom.stdenis@amd.com">
<pre wrap="">Signed-off-by: Tom St Denis <a class="moz-txt-link-rfc2396E" href="mailto:tom.stdenis@amd.com"><tom.stdenis@amd.com></a>
(v2): Add domain to iova debugfs
(v3): Add true read/write methods to access system memory of pages
mapped to the device
(v4): Move get_domain call out of loop and return on error
---
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 114 ++++++++++++++++++++++++++++++++
1 file changed, 114 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 50d20903de4f..71a2fdc91a85 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -43,6 +43,7 @@
#include <linux/swap.h>
#include <linux/pagemap.h>
#include <linux/debugfs.h>
+#include <linux/iommu.h>
#include "amdgpu.h"
#include "amdgpu_trace.h"
#include "bif/bif_4_1_d.h"
@@ -1810,6 +1811,118 @@ static const struct file_operations amdgpu_ttm_gtt_fops = {
#endif
+static void *transform_page(uint64_t phys)
+{
+ if (PageHighMem(pfn_to_page(PFN_DOWN(phys))))
+ return kmap(pfn_to_page(PFN_DOWN(phys)));
+ else
+ return __va(phys);
+}
+
+static void untransform_page(uint64_t phys)
+{
+ if (PageHighMem(pfn_to_page(PFN_DOWN(phys))))
+ return kunmap(pfn_to_page(PFN_DOWN(phys)));
+}</pre>
</blockquote>
<br>
I mentioned that in the previous patch as well, why not using
kmap()/kunmap() here directly?<br>
<br>
See kmap() for x86 for example:<br>
<blockquote type="cite">
<pre><span class="kt">void</span> <span class="o">*</span><span class="nf"><a href="http://elixir.free-electrons.com/linux/v4.2/ident/kmap">kmap</a></span><span class="p">(</span><span class="k">struct</span> <span class="n">page</span> <span class="o">*</span><span class="n">page</span><span class="p">)</span>
<span class="p">{</span>
<span class="n"><a href="http://elixir.free-electrons.com/linux/v4.2/ident/might_sleep">might_sleep</a></span><span class="p">();</span>
<span class="k">if</span> <span class="p">(</span><span class="o">!</span><span class="n"><a href="http://elixir.free-electrons.com/linux/v4.2/ident/PageHighMem">PageHighMem</a></span><span class="p">(</span><span class="n">page</span><span class="p">))</span>
<span class="k">return</span> <span class="n"><a href="http://elixir.free-electrons.com/linux/v4.2/ident/page_address">page_address</a></span><span class="p">(</span><span class="n">page</span><span class="p">);</span>
<span class="k">return</span> <span class="n"><a href="http://elixir.free-electrons.com/linux/v4.2/ident/kmap_high">kmap_high</a></span><span class="p">(</span><span class="n">page</span><span class="p">);</span>
<span class="p">}</span></pre>
</blockquote>
<br>
Both normal as well as highmem are correctly handled here.<br>
<br>
Regards,<br>
Christian.<br>
<br>
<blockquote type="cite"
cite="mid:20170919112057.24377-1-tom.stdenis@amd.com">
<pre wrap="">
+
+static ssize_t amdgpu_iova_to_phys_read(struct file *f, char __user *buf,
+ size_t size, loff_t *pos)
+{
+ struct amdgpu_device *adev = file_inode(f)->i_private;
+ ssize_t result, n;
+ int r;
+ uint64_t phys;
+ void *ptr;
+ struct iommu_domain *dom;
+
+ dom = iommu_get_domain_for_dev(adev->dev);
+ if (!dom)
+ return -EFAULT;
+
+ result = 0;
+ while (size) {
+ // get physical address and map
+ phys = iommu_iova_to_phys(dom, *pos);
+
+ // copy upto one page
+ if (size > PAGE_SIZE)
+ n = PAGE_SIZE;
+ else
+ n = size;
+
+ // to end of the page
+ if (((*pos & (PAGE_SIZE - 1)) + n) >= PAGE_SIZE)
+ n = PAGE_SIZE - (*pos & (PAGE_SIZE - 1));
+
+ ptr = transform_page(phys);
+ if (!ptr)
+ return -EFAULT;
+
+ r = copy_to_user(buf, ptr, n);
+ untransform_page(phys);
+ if (r)
+ return -EFAULT;
+
+ *pos += n;
+ size -= n;
+ result += n;
+ }
+
+ return result;
+}
+
+static ssize_t amdgpu_iova_to_phys_write(struct file *f, const char __user *buf,
+ size_t size, loff_t *pos)
+{
+ struct amdgpu_device *adev = file_inode(f)->i_private;
+ ssize_t result, n;
+ int r;
+ uint64_t phys;
+ void *ptr;
+ struct iommu_domain *dom;
+
+ dom = iommu_get_domain_for_dev(adev->dev);
+ if (!dom)
+ return -EFAULT;
+
+ result = 0;
+ while (size) {
+ // get physical address and map
+ phys = iommu_iova_to_phys(dom, *pos);
+
+ // copy upto one page
+ if (size > PAGE_SIZE)
+ n = PAGE_SIZE;
+ else
+ n = size;
+
+ // to end of the page
+ if (((*pos & (PAGE_SIZE - 1)) + n) >= PAGE_SIZE)
+ n = PAGE_SIZE - (*pos & (PAGE_SIZE - 1));
+
+ ptr = transform_page(phys);
+ if (!ptr)
+ return -EFAULT;
+
+ r = copy_from_user(ptr, buf, n);
+ untransform_page(phys);
+ if (r)
+ return -EFAULT;
+
+ *pos += n;
+ size -= n;
+ result += n;
+ }
+
+ return result;
+}
+
+static const struct file_operations amdgpu_ttm_iova_fops = {
+ .owner = THIS_MODULE,
+ .read = amdgpu_iova_to_phys_read,
+ .write = amdgpu_iova_to_phys_write,
+ .llseek = default_llseek
+};
static const struct {
char *name;
@@ -1820,6 +1933,7 @@ static const struct {
#ifdef CONFIG_DRM_AMDGPU_GART_DEBUGFS
{ "amdgpu_gtt", &amdgpu_ttm_gtt_fops, TTM_PL_TT },
#endif
+ { "amdgpu_iova", &amdgpu_ttm_iova_fops, TTM_PL_SYSTEM },
};
#endif
</pre>
</blockquote>
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