On 12/17/2014 07:09 PM, Arnd Bergmann wrote:
On Wednesday 17 December 2014 18:24:43 Murali Karicheri wrote:
On 12/17/2014 04:56 PM, Arnd Bergmann wrote:
On Wednesday 17 December 2014 13:02:23 Murali Karicheri wrote:
What's wrong with using arch_setup_dma_ops() from PCI as suggested
previously?
+Will Deacon
I had originally written a code based on that line as below. But
dma-ranges property is also used by ppc and other architectures in the
pci device DT node. So I wasn't sure how this code impact PCI driver
functionality on those platforms. Hence used a simpler change as all
that is needed for keystone is to get the dma_pfn_offset rightly set in
the pci slave device.
But in your patch, you don't call arch_setup_dma_ops() at all.
Initially I had a function implemented as below for this in of_pci.c.
+ * of_pci_dma_configure - Setup DMA configuration for a pci device
+ * @dev: pci device to apply DMA configuration
+ *
+ * Try to get devices's DMA configuration from DT and update it
+ * accordingly. This is a similar to of_dma_configure() for platform
+ * devices.
+ *
+ */
+void of_pci_dma_configure(struct pci_dev *dev)
+{
+ struct device *host_bridge, *parent;
+ struct pci_bus *bus = dev->bus;
+ u64 dma_addr, paddr, size;
+ int ret;
+
+ while (!pci_is_root_bus(bus))
+ bus = bus->parent;
+ host_bridge = bus->bridge;
+
+ parent = host_bridge->parent;
+ if (parent->of_node) {
so far it looks good, although we may want to introduce
a helper function to get the of_node.
Will add
+ /*
+ * if dma-coherent property exist, call arch hook to setup
+ * dma coherent operations.
+ */
+ if (of_dma_is_coherent(parent->of_node)) {
+ set_arch_dma_coherent_ops(&dev->dev);
+ dev_info(&dev->dev, "device is dma coherent\n");
+ }
set_arch_dma_coherent_ops no longer exists. Just keep the flag in a
local variable
Ok.
+ /*
+ * if dma-ranges property doesn't exist - just return else
+ * setup the dma offset
+ */
+ ret = of_dma_get_range(parent->of_node,&dma_addr,
&paddr,&size);
+ if (ret< 0) {
+ dev_info(&dev->dev, "no dma range information to
setup\n");
+ printk("no dma range information to setup\n");
+ return;
+ }
+
+ /* DMA ranges found. Calculate and set dma_pfn_offset */
+ dev->dev.dma_pfn_offset = PFN_DOWN(paddr - dma_addr);
+ dev_info(&dev->dev, "dma_pfn_offset(%#08lx)\n",
dev->dev.dma_pfn_offset);
Same for the offset and size here, then pass all of the above into
arch_setup_dma_ops. This is also where we need to hook up the iommu
support once we decide how to make that work with the ARM SMMU.
Ok. I will make this similar to of_dma_configure() that can be called
from pci/probe.c
Murali
Will, I think we may have a problem on ARM64 now, since we only replaced
set_arch_dma_coherent_ops on ARM32 but not ARM64. Can you send a fix for
this? Without that, we don't have any coherent operations on ARM64 any
more, unless I'm missing something.
Arnd
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--
Murali Karicheri
Linux Kernel, Texas Instruments
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