[PATCH V6 2/5] PCI: Adapt pci_register_io_range() for indirect-IO and PCI I/O translation
From: helgaas@kernel.org (Bjorn Helgaas)
Date: 2017-01-31 00:12:04
Also in:
linux-devicetree, linux-pci, linux-serial, lkml
On Tue, Jan 24, 2017 at 03:05:22PM +0800, zhichang.yuan wrote:
After indirect-IO is introduced, system must can assigned indirect-IO devices with logical I/O ranges which are different from those for PCI I/O devices. Otherwise, I/O accessors can't identify whether the I/O port is for memory mapped I/O or indirect-IO.
Maybe: We must assign logical I/O port space for indirect I/O such that the I/O accessors can tell whether a logical I/O port refers to memory- mapped I/O space or indirect I/O space.
As current helper, pci_register_io_range(), is used for PCI I/O ranges registration and translation, indirect-IO devices should also apply these helpers to manage the I/O ranges. It will be easy to ensure the assigned logical I/O ranges unique. But for indirect-IO devices, there is no cpu address. The current pci_register_io_range() can not work for this case. This patch makes some changes on the pci_register_io_range() to support the I/O range registration with device's fwnode also. After this, the indirect-IO devices can register the device-local I/O range to system logical I/O and easily perform the translation between device-local I/O range and sytem logical I/O range.
-int __weak pci_register_io_range(phys_addr_t addr, resource_size_t size) +int __weak pci_register_io_range(struct fwnode_handle *node, phys_addr_t addr, + resource_size_t size, unsigned long *port)
Why is this __weak? It looks like it's been __weak since its
introduction by 41f8bba7f555 ("of/pci: Add pci_register_io_range() and
pci_pio_to_address()"), but I don't see any other implementations of
it.
Can you add a patch that does nothing but make this non-weak?
+#else + /* + * powerpc and microblaze have their own registration, + * just look up the value here
Can you include a pointer to the powerpc and microblaze registration code here? It's conceivable that somebody could generalize this enough to support powerpc and microblaze as well.
quoted hunk ↗ jump to hunk
--- a/include/linux/pci.h +++ b/include/linux/pci.h@@ -34,6 +34,9 @@ #include <linux/pci_ids.h> +/* the macro below flags an invalid cpu address + * and is used by IO special hosts */
s/cpu/CPU/ Use conventional multi-line comment style: /* * IO_RANGE_IOEXT flags an invalid CPU address ... */
+#define IO_RANGE_IOEXT (resource_size_t)(-1ull)
And put this close to related things, e.g., pci_register_io_range(), instead of just dropping it in at the top of the file.
quoted hunk ↗ jump to hunk
/* * The PCI interface treats multi-function devices as independent * devices. The slot/function address of each device is encoded@@ -1197,8 +1200,8 @@ int __must_check pci_bus_alloc_resource(struct pci_bus *bus, resource_size_t), void *alignf_data); - -int pci_register_io_range(phys_addr_t addr, resource_size_t size); +int pci_register_io_range(struct fwnode_handle *node, phys_addr_t addr, + resource_size_t size, unsigned long *port); unsigned long pci_address_to_pio(phys_addr_t addr); phys_addr_t pci_pio_to_address(unsigned long pio); int pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr);-- 1.9.1