On Wed, Jul 22, 2015 at 11:15:53AM +0100, Marc Zyngier wrote:
> On 22/07/15 10:30, Zhou Wang wrote:
> > On 2015/7/13 18:43, Lorenzo Pieralisi wrote:
> >> On ARM PCI systems relying on the pcibios API to initialize PCI host
> >> controllers, the pcibios_msi_controller weak callback is used to look-up
> >> the msi_controller pointer, through pci_sys_data msi_ctrl pointer.
> >>
> >> pci_sys_data is an arch specific structure, which prevents using the
> >> same mechanism (so same PCI host controller drivers) on ARM64 systems.
> >>
> >> Since the struct pci_bus already contains an msi_controller pointer and
> >> the kernel already uses it to look-up the msi controller,
> >> this patch converts ARM host controller and relate pcibios/host bridges
> >> initialization routines so that the msi_controller pointer look-up can be
> >> carried out by PCI core code through the struct pci_bus msi pointer,
> >> removing the need for arch specific pcibios_msi_controller callback
> >> and the related pci_sys_data msi_ctrl pointer.
> >>
> >> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> >> Cc: Pratyush Anand <pratyush.anand@xxxxxxxxx>
> >> Cc: Arnd Bergmann <arnd@xxxxxxxx>
> >> Cc: Jingoo Han <jingoohan1@xxxxxxxxx>
> >> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> >> Cc: Simon Horman <horms@xxxxxxxxxxxx>
> >> Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
> >> Cc: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx>
> >> Cc: Thierry Reding <thierry.reding@xxxxxxxxx>
> >> Cc: Michal Simek <michal.simek@xxxxxxxxxx>
> >> Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
> >> ---
> >> Bjorn, all,
> >>
> >> I am posting this patch to sound out if that's a reasonable approach.
> >> xgene implements MSI look-up this way at present and this would represent
> >> another step forward towards having common drivers for ARM/ARM64, comments
> >> and testing welcome.
> >>
> >> Thanks,
> >> Lorenzo
> >>
> >> arch/arm/include/asm/mach/pci.h | 3 ---
> >> arch/arm/kernel/bios32.c | 35 +++++++++++++++++------------------
> >> drivers/pci/host/pcie-designware.c | 9 +++++++--
> >> drivers/pci/host/pcie-xilinx.c | 12 ++++++++++--
> >> 4 files changed, 34 insertions(+), 25 deletions(-)
> >>
> >> diff --git a/arch/arm/include/asm/mach/pci.h b/arch/arm/include/asm/mach/pci.h
> >> index 28b9bb3..32abc0c 100644
> >> --- a/arch/arm/include/asm/mach/pci.h
> >> +++ b/arch/arm/include/asm/mach/pci.h
> >> @@ -42,9 +42,6 @@ struct hw_pci {
> >> * Per-controller structure
> >> */
> >> struct pci_sys_data {
> >> -#ifdef CONFIG_PCI_MSI
> >> - struct msi_controller *msi_ctrl;
> >> -#endif
> >> struct list_head node;
> >> int busnr; /* primary bus number */
> >> u64 mem_offset; /* bus->cpu memory mapping offset */
> >> diff --git a/arch/arm/kernel/bios32.c b/arch/arm/kernel/bios32.c
> >> index fcbbbb1..c841b33 100644
> >> --- a/arch/arm/kernel/bios32.c
> >> +++ b/arch/arm/kernel/bios32.c
> >> @@ -18,15 +18,6 @@
> >>
> >> static int debug_pci;
> >>
> >> -#ifdef CONFIG_PCI_MSI
> >> -struct msi_controller *pcibios_msi_controller(struct pci_dev *dev)
> >> -{
> >> - struct pci_sys_data *sysdata = dev->bus->sysdata;
> >> -
> >> - return sysdata->msi_ctrl;
> >> -}
> >> -#endif
> >> -
> >> /*
> >> * We can't use pci_get_device() here since we are
> >> * called from interrupt context.
> >> @@ -462,9 +453,6 @@ static void pcibios_init_hw(struct device *parent, struct hw_pci *hw,
> >> if (!sys)
> >> panic("PCI: unable to allocate sys data!");
> >>
> >> -#ifdef CONFIG_PCI_MSI
> >> - sys->msi_ctrl = hw->msi_ctrl;
> >> -#endif
> >> sys->busnr = busnr;
> >> sys->swizzle = hw->swizzle;
> >> sys->map_irq = hw->map_irq;
> >> @@ -483,14 +471,25 @@ static void pcibios_init_hw(struct device *parent, struct hw_pci *hw,
> >> break;
> >> }
> >>
> >> - if (hw->scan)
> >> + if (hw->scan) {
> >> sys->bus = hw->scan(nr, sys);
> >> - else
> >> - sys->bus = pci_scan_root_bus(parent, sys->busnr,
> >> - hw->ops, sys, &sys->resources);
> >> + if (!sys->bus)
> >> + panic("PCI: unable to scan bus!");
> >> + } else {
> >> + sys->bus = pci_create_root_bus(parent,
> >> + sys->busnr,
> >> + hw->ops, sys,
> >> + &sys->resources);
> >> + if (WARN_ON(!sys->bus)) {
> >> + kfree(sys);
> >> + break;
> >> + }
> >> +#ifdef CONFIG_PCI_MSI
> >> + sys->bus->msi = hw->msi_ctrl;
> >> +#endif
> >>
> >> - if (!sys->bus)
> >> - panic("PCI: unable to scan bus!");
> >> + pci_scan_child_bus(sys->bus);
> >> + }
> >>
> >> busnr = sys->bus->busn_res.end + 1;
> >>
> >> diff --git a/drivers/pci/host/pcie-designware.c b/drivers/pci/host/pcie-designware.c
> >> index 69486be..e584dfa 100644
> >> --- a/drivers/pci/host/pcie-designware.c
> >> +++ b/drivers/pci/host/pcie-designware.c
> >> @@ -526,7 +526,6 @@ int dw_pcie_host_init(struct pcie_port *pp)
> >>
> >> #ifdef CONFIG_PCI_MSI
> >> dw_pcie_msi_chip.dev = pp->dev;
> >> - dw_pci.msi_ctrl = &dw_pcie_msi_chip;
> >> #endif
> >>
> >> dw_pci.nr_controllers = 1;
> >> @@ -708,11 +707,17 @@ static struct pci_bus *dw_pcie_scan_bus(int nr, struct pci_sys_data *sys)
> >> struct pcie_port *pp = sys_to_pcie(sys);
> >>
> >> pp->root_bus_nr = sys->busnr;
> >> - bus = pci_scan_root_bus(pp->dev, sys->busnr,
> >> + bus = pci_create_root_bus(pp->dev, sys->busnr,
> >> &dw_pcie_ops, sys, &sys->resources);
> >> if (!bus)
> >> return NULL;
> >>
> >> +#ifdef CONFIG_PCI_MSI
> >> + bus->msi = &dw_pcie_msi_chip;
> >> +#endif
> >> +
> >> + pci_scan_child_bus(bus);
> >> +
> >> if (bus && pp->ops->scan_bus)
> >> pp->ops->scan_bus(pp);
> >>
> >> diff --git a/drivers/pci/host/pcie-xilinx.c b/drivers/pci/host/pcie-xilinx.c
> >> index f1a06a0..b21eb7d 100644
> >> --- a/drivers/pci/host/pcie-xilinx.c
> >> +++ b/drivers/pci/host/pcie-xilinx.c
> >> @@ -647,9 +647,18 @@ static struct pci_bus *xilinx_pcie_scan_bus(int nr, struct pci_sys_data *sys)
> >> struct pci_bus *bus;
> >>
> >> port->root_busno = sys->busnr;
> >> - bus = pci_scan_root_bus(port->dev, sys->busnr, &xilinx_pcie_ops,
> >> + bus = pci_create_root_bus(port->dev, sys->busnr, &xilinx_pcie_ops,
> >> sys, &sys->resources);
> >>
> >> + if (!bus)
> >> + return NULL;
> >> +
> >> +#ifdef CONFIG_PCI_MSI
> >> + bus->msi = &xilinx_pcie_msi_chip;
> >> +#endif
> >> +
> >> + pci_scan_child_bus(bus);
> >> +
> >> return bus;
> >> }
> >>
> >> @@ -847,7 +856,6 @@ static int xilinx_pcie_probe(struct platform_device *pdev)
> >>
> >> #ifdef CONFIG_PCI_MSI
> >> xilinx_pcie_msi_chip.dev = port->dev;
> >> - hw.msi_ctrl = &xilinx_pcie_msi_chip;
> >> #endif
> >> pci_common_init_dev(dev, &hw);
> >>
> >>
> >
> > Hi Lorenzo,
> >
> > I wonder if we can delete weak pcibios_msi_controller and the call in
> > pci_msi_controller in drivers/pci/msi.c
>
> Yeah, I think we can replace it with a straight "return NULL;" in
> pci_msi_controller, as ARM is the only arch to implement this function
> (which Lorenzo now removes).
Agreed, I did not do it since I wanted to get feedback on the approach
first, if we agree that's the right thing to do we can kill
pcibios_msi_controller() in the core too (since it becomes unused).
Lorenzo
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