On 18/03/15 11:22, Yong Wu wrote:
Hi Tomasz,
Thanks very much for your review. please help check below.
The others I will fix in the next version.
Hi Robin,
There are some place I would like you can have a look and give me
some suggestion.
On Wed, 2015-03-11 at 19:53 +0900, Tomasz Figa wrote:
Hi,
Please find next part of my comments inline.
On Fri, Mar 6, 2015 at 7:48 PM, <yong.wu@xxxxxxxxxxxx> wrote:
[snip]
+/*
+ * pimudev is a global var for dma_alloc_coherent.
+ * It is not accepatable, we will delete it if "domain_alloc" is enabled
It looks like we indeed need to use dma_alloc_coherent() and we don't
have a good way to pass the device pointer to domain_init callback.
If you don't expect SoCs in the nearest future to have multiple M4U
blocks, then I guess this global variable could stay, after changing
the comment into an explanation why it's correct. Also it should be
moved to the top of the file, below #include directives, as this is
where usually global variables are located.
@Robin,
We have merged this patch[0] in order to delete the global var, But
it seems that your patch of "arm64:IOMMU" isn't based on it right row.
it will build fail.
Yeah, I've not yet managed to try pulling in that series (much as I
approve of it), partly as I know doing so is going to lean towards a
not-insignificant rework and I'd rather avoid picking up more unmerged
dependencies to block getting _something_ in for arm64 (which we can
then improve).
[0]:http://lists.linuxfoundation.org/pipermail/iommu/2015-January/011939.html
+ */
+static struct device *pimudev;
+
[snip]
+
+static int mtk_iommu_attach_device(struct iommu_domain *domain,
+ struct device *dev)
+{
+ unsigned long flags;
+ struct mtk_iommu_domain *priv = domain->priv;
+ struct mtk_iommu_info *piommu = priv->piommuinfo;
+ struct of_phandle_args out_args = {0};
+ struct device *imudev;
+ unsigned int i = 0;
+
+ if (!piommu)
Could you explain when this can happen?
If we call arch_setup_dma_ops to create a iommu domain,
it will enter iommu_dma_attach_device, then enter here. At that time, we
don't add the private data to this "struct iommu_domain *".
@Robin, Could this be improved?
Calling arch_setup_dma_ops() from the driver looks plain wrong,
especially given that you apparently attach the IOMMU to itself - if you
want your own domain you should use iommu_dma_create_domain(). I admit
that still leaves you having to dance around a bit in order to tear down
the automatic domains for now, but hopefully we'll get the core code
sorted out sooner rather than later.
+ goto imudev;
return 0;
+ else
No else needed.
+ imudev = piommu->dev;
+
+ spin_lock_irqsave(&priv->portlock, flags);
What is protected by this spinlock?
We will write a register of the local arbiter while config port. If
some modules are in the same local arbiter, it may be overwrite. so I
add it here.
+
+ while (!of_parse_phandle_with_args(dev->of_node, "iommus",
+ "#iommu-cells", i, &out_args)) {
+ if (1 == out_args.args_count) {
Can we be sure that this is actually referring to our IOMMU?
Maybe this should be rewritten to
if (out_args.np != imudev->of_node)
continue;
if (out_args.args_count != 1) {
dev_err(imudev, "invalid #iommu-cells property for IOMMU %s\n",
}
+ unsigned int portid = out_args.args[0];
+
+ dev_dbg(dev, "iommu add port:%d\n", portid);
imudev should be used here instead of dev.
+
+ mtk_iommu_config_port(piommu, portid);
+
+ if (i == 0)
+ dev->archdata.dma_ops =
+ piommu->dev->archdata.dma_ops;
Shouldn't this be set automatically by IOMMU or DMA mapping core?
@Robin,
In the original "arm_iommu_attach_device" of arm/mm, it will call
set_dma_ops to add iommu_ops for each iommu device.
But iommu_dma_attach_device don't help this, so I have to add it here.
Could this be improved?
If you implemented a simple of_xlate callback so that the core code
handles the dma_ops as intended, I think the simplest cheat would be to
check the client device's domain, either on attachment or when they
start mapping/unmapping, and move them to your own domain if necessary.
I'm putting together a v3 of the DMA mapping series, so I'll have a look
to see if I can squeeze in a way to make that a bit less painful until
we solve it properly.
Robin.
+ }
+ i++;
+ }
+
+ spin_unlock_irqrestore(&priv->portlock, flags);
+
+imudev:
+ return 0;
+}
+
+static void mtk_iommu_detach_device(struct iommu_domain *domain,
+ struct device *dev)
+{
No hardware (de)configuration or clean-up necessary?
I will add it. Actually we design like this:If a device have attached to
iommu domain, it won't detach from it.
+}
+
[snip]
+
+ piommu->protect_va = devm_kmalloc(piommu->dev, MTK_PROTECT_PA_ALIGN*2,
style: Operators like * should have space on both sides.
+ GFP_KERNEL);
Shouldn't dma_alloc_coherent() be used for this?
We don't care the data in it. I think they are the same. Could you
help tell me why dma_alloc_coherent may be better.
+ if (!piommu->protect_va)
+ goto protect_err;
Please return -ENOMEM here directly, as there is nothing to clean up
in this case.
[snip]
+ dev_err(piommu->dev, "IRQ request %d failed\n",
+ piommu->irq);
+ goto hw_err;
+ }
+
+ iommu_set_fault_handler(domain, mtk_iommu_fault_handler, piommu);
I don't see any other drivers doing this. Isn't this for upper layers,
so that they can set their own generic fault handlers?
I think that this function is related with the iommu domain, we
have only one multimedia iommu domain. so I add it after the iommu
domain are created.
+
+ dev_set_drvdata(piommu->dev, piommu);
This should be set before allowing the interrupt to fire. In other
words, the driver should be fully set up at the time of enabling the
IRQ.
+
+ return 0;
style: Missing blank line.
+hw_err:
+ arch_teardown_dma_ops(piommu->dev);
+pte_err:
+ kmem_cache_destroy(piommu->m4u_pte_kmem);
+protect_err:
+ dev_err(piommu->dev, "probe error\n");
Please replace this with specific messages for all errors (in case the
called function doesn't already print one like kmalloc and friends).
+ return 0;
Returning 0, which means success, doesn't look like a good idea for
signalling a failure. Please return the correct error code as received
from function that errors out if possible.
End of part 3.
Best regards,
Tomasz
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