On 13.05.2016 13:31, Rafael J. Wysocki wrote:
On Fri, May 13, 2016 at 1:25 PM, Jayachandran C <jchandra@xxxxxxxxxxxx> wrote:
On Tue, May 10, 2016 at 8:49 PM, Tomasz Nowicki <tn@xxxxxxxxxxxx> wrote:
This patch is going to implement generic PCI host controller for
ACPI world, similar to what pci-host-generic.c driver does for DT world.
All such drivers, which we have seen so far, were implemented within
arch/ directory since they had some arch assumptions (x86 and ia64).
However, they all are doing similar thing, so it makes sense to find
some common code and abstract it into the generic driver.
In order to handle PCI config space regions properly, we define new
MCFG interface which does sanity checks on MCFG table and keeps its
root pointer. User is able to lookup MCFG regions based on that root
pointer and specified domain:bus_start:bus_end touple. We are using
pci_mmcfg_late_init old prototype to avoid another function name.
The implementation of pci_acpi_scan_root() looks up the MCFG entries
and sets up a new mapping (regions are not mapped until host controller ask
for it). Generic PCI functions are used for accessing config space.
Driver selects PCI_ECAM and uses functions from drivers/pci/ecam.h
to create and access ECAM mappings.
As mentioned in Kconfig help section, ACPI_PCI_HOST_GENERIC choice
should be made on a per-architecture basis.
Signed-off-by: Tomasz Nowicki <tn@xxxxxxxxxxxx>
Signed-off-by: Jayachandran C <jchandra@xxxxxxxxxxxx>
---
[....]
diff --git a/drivers/pci/ecam.h b/drivers/pci/ecam.h
index 1ad2176..1cccf57 100644
--- a/drivers/pci/ecam.h
+++ b/drivers/pci/ecam.h
@@ -45,6 +45,11 @@ struct pci_config_window {
void __iomem *win; /* 64-bit single mapping */
void __iomem **winp; /* 32-bit per bus mapping */
};
+#ifdef CONFIG_ACPI_PCI_HOST_GENERIC
+ struct acpi_device *companion; /* ACPI companion device */
+#endif
+ int domain;
+
};
Using struct pci_config_window to pass along domain and
companion looks bad. I think there are two possible options
to do this better:
1. add a 'struct fwnode_handle *' or 'struct device *parent_dev'
instead of the companion and domain fields above. In case of
ACPI either of them can be used to get the acpi_device and
both domain and companion can be set from that.
2. make pci_config_window fully embeddable by moving allocation
out of pci_ecam_create to its callers. Then it can be embedded
into acpi_pci_generic_root_info, and container_of can be used
to get acpi info from ->sysdata.
The first option should be easier to implement but the second may
be better on long run. I would leave it to the Bjorn or Rafael to
suggest which is preferred.
Personally, I'd probably try to use fwnode_handle, but the second
option makes sense too in principle.
Thanks for suggestions. I will try to use fwnode_handle
Tomasz
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