Re: [PATCH v9 08/21] ARM64 / ACPI: Introduce PCI stub functions for ACPI

From: Hanjun Guo
Date: Tue Mar 10 2015 - 05:35:15 EST

On 2015å03æ09æ 23:01, Liviu Dudau wrote:
On Wed, Feb 25, 2015 at 08:39:48AM +0000, Hanjun Guo wrote:
CONFIG_ACPI depends CONFIG_PCI on x86 and ia64, in ARM64 server
world we will have PCIe in most cases, but some of them may not,
make CONFIG_ACPI depend CONFIG_PCI on ARM64 will satisfy both.

With that case, we need some arch dependent PCI functions to
access the config space before the PCI root bridge is created, and
pci_acpi_scan_root() to create the PCI root bus. So introduce
some stub function here to make ACPI core compile and revisit
them later when implemented on ARM64.

CC: Liviu Dudau <Liviu.Dudau@xxxxxxx>
CC: Catalin Marinas <catalin.marinas@xxxxxxx>
CC: Will Deacon <will.deacon@xxxxxxx>
Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>
Tested-by: Yijing Wang <wangyijing@xxxxxxxxxx>
Tested-by: Mark Langsdorf <mlangsdo@xxxxxxxxxx>
Tested-by: Jon Masters <jcm@xxxxxxxxxx>
Tested-by: Timur Tabi <timur@xxxxxxxxxxxxxx>
Tested-by: Robert Richter <rrichter@xxxxxxxxxx>
Acked-by: Robert Richter <rrichter@xxxxxxxxxx>
Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
arch/arm64/include/asm/pci.h | 6 ++++++
arch/arm64/kernel/pci.c | 25 +++++++++++++++++++++++++
2 files changed, 31 insertions(+)

diff --git a/arch/arm64/include/asm/pci.h b/arch/arm64/include/asm/pci.h
index 872ba93..fded096 100644
--- a/arch/arm64/include/asm/pci.h
+++ b/arch/arm64/include/asm/pci.h
@@ -24,6 +24,12 @@
#define PCI_DMA_BUS_IS_PHYS (0)


Hi Liviu,

+static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel)
+ /* no legacy IRQ on arm64 */
+ return -ENODEV;

Could you explain to me what situation you encountered where you needed
to define this? I'm trying to figure out when this would be needed and the
only thing I can come up with would be for drivers/pnp/resource.c, but that
is guarded by #ifdef CONFIG_PCI, which would mean that you should move this
a bit further down in the file,

Agreed, will move it to #ifdef CONFIG_PCI .. #endif.

but also contradicts the last comment on
this patch (i.e. PCI on ACPI is not really implemented, so presumably
CONFIG_PCI is not enabled?)

CONFIG_ACPI depends on CONFIG_PCI in the Kconfig, so CONFIG_PCI will be
enabled even PCI on ACPI is not really implemented now, did I
understand your question correctly?

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