On Wed, May 11, 2016 at 05:43:14PM -0500, Bjorn Helgaas wrote:
> On Wed, May 11, 2016 at 10:30:51PM +0200, Rafael J. Wysocki wrote:
> > On Wed, May 11, 2016 at 12:11 PM, Lorenzo Pieralisi
> > <lorenzo.pieralisi@xxxxxxx> wrote:
> > > On Tue, May 10, 2016 at 08:37:00PM +0200, Rafael J. Wysocki wrote:
> > >> On Tue, May 10, 2016 at 5:19 PM, Tomasz Nowicki <tn@xxxxxxxxxxxx> wrote:
> > >> > This patch provides a way to set the ACPI companion in PCI code.
> > >> > We define acpi_pci_set_companion() to set the ACPI companion pointer and
> > >> > call it from PCI core code. The function is stub for now.
> > >> >
> > >> > Signed-off-by: Jayachandran C <jchandra@xxxxxxxxxxxx>
> > >> > Signed-off-by: Tomasz Nowicki <tn@xxxxxxxxxxxx>
> > >> > ---
> > >> > drivers/pci/probe.c | 2 ++
> > >> > include/linux/pci-acpi.h | 4 ++++
> > >> > 2 files changed, 6 insertions(+)
> > >> >
> > >> > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> > >> > index 8004f67..fb0b752 100644
> > >> > --- a/drivers/pci/probe.c
> > >> > +++ b/drivers/pci/probe.c
> > >> > @@ -12,6 +12,7 @@
> > >> > #include <linux/slab.h>
> > >> > #include <linux/module.h>
> > >> > #include <linux/cpumask.h>
> > >> > +#include <linux/pci-acpi.h>
> > >> > #include <linux/pci-aspm.h>
> > >> > #include <linux/aer.h>
> > >> > #include <linux/acpi.h>
> > >> > @@ -2141,6 +2142,7 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
> > >> > bridge->dev.parent = parent;
> > >> > bridge->dev.release = pci_release_host_bridge_dev;
> > >> > dev_set_name(&bridge->dev, "pci%04x:%02x", pci_domain_nr(b), bus);
> > >> > + acpi_pci_set_companion(bridge);
> > >>
> > >> Yes, we'll probably add something similar here.
> > >>
> > >> Do I think now is the right time to do that? No.
> > >>
> > >> > error = pcibios_root_bridge_prepare(bridge);
> > >> > if (error) {
> > >> > kfree(bridge);
> > >> > diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
> > >> > index 09f9f02..1baa515 100644
> > >> > --- a/include/linux/pci-acpi.h
> > >> > +++ b/include/linux/pci-acpi.h
> > >> > @@ -111,6 +111,10 @@ static inline void acpi_pci_add_bus(struct pci_bus *bus) { }
> > >> > static inline void acpi_pci_remove_bus(struct pci_bus *bus) { }
> > >> > #endif /* CONFIG_ACPI */
> > >> >
> > >> > +static inline void acpi_pci_set_companion(struct pci_host_bridge *bridge)
> > >> > +{
> > >> > +}
> > >> > +
> > >> > static inline int acpi_pci_bus_domain_nr(struct pci_bus *bus)
> > >> > {
> > >> > return 0;
> > >> > --
> > >>
> > >> Honestly, to me it looks like this series is trying very hard to avoid
> > >> doing any PCI host bridge configuration stuff from arch/arm64/
> > >> although (a) that might be simpler and (b) it would allow us to
> > >> identify the code that's common between *all* architectures using ACPI
> > >> support for host bridge configuration and to move *that* to a common
> > >> place later. As done here it seems to be following the "ARM64 is
> > >> generic and the rest of the world is special" line which isn't really
> > >> helpful.
> > >
> > > I think patch [1-2] should be merged regardless (they may require minor
> > > tweaks if we decide to move pci_acpi_scan_root() to arch/arm64 though,
> > > for include files location). I guess you are referring to patch 8 in
> > > your comments above, which boils down to deciding whether:
> > >
> > > - pci_acpi_scan_root() (and unfortunately all the MCFG/ECAM handling that
> > > goes with it) should live in arch/arm64 or drivers/acpi
> >
> > To be precise, everything under #ifdef CONFIG_ACPI_PCI_HOST_GENERIC or
> > equivalent is de facto ARM64-specific, because (as it stands in the
> > patch series) ARM64 is the only architecture that will select that
> > option. Unless you are aware of any more architectures planning to
> > use ACPI (and I'm not aware of any), it will stay the only
> > architecture selecting it in the foreseeable future.
> >
> > Therefore you could replace CONFIG_ACPI_PCI_HOST_GENERIC with
> > CONFIG_ARM64 everywhere in that code which is why in my opinion the
> > code should live somewhere under arch/arm64/.
> >
> > Going forward, it should be possible to identify common parts of the
> > PCI host bridge configuration code in arch/ and move it to
> > drivers/acpi/ or drivers/pci/, but I bet that won't be the entire code
> > this series puts under CONFIG_ACPI_PCI_HOST_GENERIC.
> >
> > The above leads to a quite straightforward conclusion about the order
> > in which to do things: I'd add ACPI support for PCI host bridge on
> > ARM64 following what's been done on ia64 (as x86 is more quirky and
> > kludgy overall) as far as reasonably possible first and then think
> > about moving common stuff to a common place.
>
> That does seem like a reasonable approach. I had hoped to get more of
> this in for v4.7, but we don't have much time left. Maybe some of
> Rafael's comments can be addressed by moving and slight restructuring
> and we can still squeeze it in.
Yes, it seems like a reasonable approach, as long as we accept that
part of this series has to live in arch/arm64 otherwise we are going
round in circles (because that's the gist of this discussion, to
decide where this code has to live, I do not think there is any objection
to the code per-se anymore).
I suggest we post a v8 (with code move to arch/arm64) end of merge
window (or you prefer seeing patches now to prevent any additional
changes later ?), my aim is to get this into -next (whether via arm64 or
pci tree it has to be decided) as early as possible for next cycle (-rc1)
so that it can get exposure and testing, I do not think that missing the
merge window is a big issue if we agree that the code is ready to go.
> The first three patches:
>
> PCI: Provide common functions for ECAM mapping
> PCI: generic, thunder: Use generic ECAM API
> PCI, of: Move PCI I/O space management to PCI core code
>
> seem relatively straightforward, and I applied them to pci/arm64 with
> the intent of merging them unless there are objections. I made the
> following tweaks, mainly to try to improve some error messages:
Ok, thanks a lot !
Lorenzo
> diff --git a/drivers/pci/ecam.c b/drivers/pci/ecam.c
> index 3d52005..e1add01 100644
> --- a/drivers/pci/ecam.c
> +++ b/drivers/pci/ecam.c
> @@ -24,9 +24,9 @@
> #include "ecam.h"
>
> /*
> - * On 64 bit systems, we do a single ioremap for the whole config space
> - * since we have enough virtual address range available. On 32 bit, do an
> - * ioremap per bus.
> + * On 64-bit systems, we do a single ioremap for the whole config space
> + * since we have enough virtual address range available. On 32-bit, we
> + * ioremap the config space for each bus individually.
> */
> static const bool per_bus_mapping = !config_enabled(CONFIG_64BIT);
>
> @@ -42,6 +42,7 @@ struct pci_config_window *pci_ecam_create(struct device *dev,
> {
> struct pci_config_window *cfg;
> unsigned int bus_range, bus_range_max, bsz;
> + struct resource *conflict;
> int i, err;
>
> if (busr->start > busr->end)
> @@ -58,10 +59,10 @@ struct pci_config_window *pci_ecam_create(struct device *dev,
> bus_range = resource_size(&cfg->busr);
> bus_range_max = resource_size(cfgres) >> ops->bus_shift;
> if (bus_range > bus_range_max) {
> - dev_warn(dev, "bus max %#x reduced to %#x",
> - bus_range, bus_range_max);
> bus_range = bus_range_max;
> cfg->busr.end = busr->start + bus_range - 1;
> + dev_warn(dev, "ECAM area %pR can only accommodate %pR (reduced from %pR desired)\n",
> + cfgres, &cfg->busr, busr);
> }
> bsz = 1 << ops->bus_shift;
>
> @@ -70,9 +71,11 @@ struct pci_config_window *pci_ecam_create(struct device *dev,
> cfg->res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
> cfg->res.name = "PCI ECAM";
>
> - err = request_resource(&iomem_resource, &cfg->res);
> - if (err) {
> - dev_err(dev, "request ECAM res %pR failed\n", &cfg->res);
> + conflict = request_resource(&iomem_resource, &cfg->res);
> + if (conflict) {
> + err = -EBUSY;
> + dev_err(dev, "can't claim ECAM area %pR: address conflict with %s %pR\n",
> + &cfg->res, conflict->name, conflict);
> goto err_exit;
> }
>
> diff --git a/drivers/pci/ecam.h b/drivers/pci/ecam.h
> index 1ad2176..9878beb 100644
> --- a/drivers/pci/ecam.h
> +++ b/drivers/pci/ecam.h
> @@ -33,7 +33,7 @@ struct pci_ecam_ops {
>
> /*
> * struct to hold the mappings of a config space window. This
> - * is expected to be used as sysdata for PCI controlllers which
> + * is expected to be used as sysdata for PCI controllers that
> * use ECAM.
> */
> struct pci_config_window {
> @@ -43,11 +43,11 @@ struct pci_config_window {
> struct pci_ecam_ops *ops;
> union {
> void __iomem *win; /* 64-bit single mapping */
> - void __iomem **winp; /* 32-bit per bus mapping */
> + void __iomem **winp; /* 32-bit per-bus mapping */
> };
> };
>
> -/* create and free for pci_config_window */
> +/* create and free pci_config_window */
> struct pci_config_window *pci_ecam_create(struct device *dev,
> struct resource *cfgres, struct resource *busr,
> struct pci_ecam_ops *ops);
> @@ -56,11 +56,11 @@ void pci_ecam_free(struct pci_config_window *cfg);
> /* map_bus when ->sysdata is an instance of pci_config_window */
> void __iomem *pci_ecam_map_bus(struct pci_bus *bus, unsigned int devfn,
> int where);
> -/* default ECAM ops, bus shift 20, generic read and write */
> +/* default ECAM ops */
> extern struct pci_ecam_ops pci_generic_ecam_ops;
>
> #ifdef CONFIG_PCI_HOST_GENERIC
> -/* for DT based pci controllers that support ECAM */
> +/* for DT-based PCI controllers that support ECAM */
> int pci_host_common_probe(struct platform_device *pdev,
> struct pci_ecam_ops *ops);
> #endif
>
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