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Date: Thu, 11 Jun 2015 14:53:46 -0500
From: Suravee Suthikulanit <suravee.suthikulpanit@....com>
To: Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
<linux-kernel@...r.kernel.org>, <linux-pci@...r.kernel.org>
CC: Ralf Baechle <ralf@...ux-mips.org>,
"James E.J. Bottomley" <jejb@...isc-linux.org>,
Michael Ellerman <mpe@...erman.id.au>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Richard Henderson <rth@...ddle.net>,
"Benjamin Herrenschmidt" <benh@...nel.crashing.org>,
David Howells <dhowells@...hat.com>,
Russell King <linux@....linux.org.uk>,
Tony Luck <tony.luck@...el.com>,
"David S. Miller" <davem@...emloft.net>,
Ingo Molnar <mingo@...hat.com>,
Guenter Roeck <linux@...ck-us.net>,
Michal Simek <monstr@...str.eu>,
Chris Zankel <chris@...kel.net>, Arnd Bergmann <arnd@...db.de>,
Krzysztof Halasa <khalasa@...p.pl>,
Phil Edworthy <phil.edworthy@...esas.com>,
Jason Gunthorpe <jgunthorpe@...idianresearch.com>,
Jingoo Han <jg1.han@...sung.com>,
"Lucas Stach" <l.stach@...gutronix.de>,
Simon Horman <horms@...ge.net.au>,
"Minghuan Lian" <minghuan.Lian@...escale.com>,
Murali Karicheri <m-karicheri2@...com>,
Tanmay Inamdar <tinamdar@....com>,
Kishon Vijay Abraham I <kishon@...com>,
Thierry Reding <thierry.reding@...il.com>,
Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
Will Deacon <will.deacon@....com>,
Jayachandran C <jchandra@...adcom.com>
Subject: Re: [RFC/RFT PATCH v2] PCI: move pci_read_bridge_bases to the generic
PCI layer
For ARM64 PROBE_ONLY and non-PROBE_ONLY modes:
Reviewed and Tested-by: Suravee Suthikulpanit
<Suravee.Suthikulpanit@....com>
Please see minor comments below.
On 6/9/2015 4:01 AM, Lorenzo Pieralisi wrote:
> When a PCI bus is scanned, upon PCI bridge detection the kernel
> has to read the bridge registers to set-up its resources so that
> the PCI resource hierarchy can be validated properly.
>
> Most if not all architectures read PCI bridge registers in the
> pcibios_fixup_bus hook, that is called by the PCI generic layer
> whenever a PCI bus is scanned.
>
> Since pci_read_bridge_bases is an arch agnostic operation (and it
> is carried out on all architectures) it can be moved to the generic
> PCI layer in order to consolidate code and remove the respective
> calls from the architectures back-ends.
>
> The PCI_PROBE_ONLY flag is not checked before calling
> pci_read_bridge_buses in the generic layer since reading the bridge
> bases is not related to resources assignment; this implies that it
> can be carried out safely on PCI_PROBE_ONLY systems too and should
> not affect architectures (alpha, mips) that check the PCI_PROBE_ONLY
> flag before reading the bridge bases.
>
> In order to validate the resource hierarchy as soon as the resources
> themselves are probed (ie read from the bridge), this patch also adds
> code to pci_read_bridge_bases that claims the bridge resources, so that
> they are validated and inserted in the resource hierarchy as soon as
> the bridge bases are probed.
>
> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
> Cc: Ralf Baechle <ralf@...ux-mips.org>
> Cc: James E.J. Bottomley <jejb@...isc-linux.org>
> Cc: Michael Ellerman <mpe@...erman.id.au>
> Cc: Bjorn Helgaas <bhelgaas@...gle.com>
> Cc: Richard Henderson <rth@...ddle.net>
> Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>
> Cc: David Howells <dhowells@...hat.com>
> Cc: Russell King <linux@....linux.org.uk>
> Cc: Tony Luck <tony.luck@...el.com>
> Cc: David S. Miller <davem@...emloft.net>
> Cc: Ingo Molnar <mingo@...hat.com>
> Cc: Guenter Roeck <linux@...ck-us.net>
> Cc: Michal Simek <monstr@...str.eu>
> Cc: Chris Zankel <chris@...kel.net>
> ---
> v1->v2:
>
> - Moved pci_read_bridge_bases call to pci_scan_bridge to read bases before
> scanning devices
> - Added bridge resources claiming
>
> v1: https://lkml.org/lkml/2015/5/21/359
>
> arch/alpha/kernel/pci.c | 7 +------
> arch/frv/mb93090-mb00/pci-vdk.c | 2 --
> arch/ia64/pci/pci.c | 1 -
> arch/microblaze/pci/pci-common.c | 9 +--------
> arch/mips/pci/pci.c | 6 ------
> arch/mn10300/unit-asb2305/pci.c | 1 -
> arch/powerpc/kernel/pci-common.c | 8 +-------
> arch/x86/pci/common.c | 1 -
> arch/xtensa/kernel/pci.c | 4 ----
> drivers/parisc/dino.c | 3 ---
> drivers/parisc/lba_pci.c | 1 -
> drivers/pci/probe.c | 26 ++++++++++++++++++++++++++
> 12 files changed, 29 insertions(+), 40 deletions(-)
>
> diff --git a/arch/alpha/kernel/pci.c b/arch/alpha/kernel/pci.c
> index 82f738e..cded02c 100644
> --- a/arch/alpha/kernel/pci.c
> +++ b/arch/alpha/kernel/pci.c
> @@ -242,12 +242,7 @@ pci_restore_srm_config(void)
>
> void pcibios_fixup_bus(struct pci_bus *bus)
> {
> - struct pci_dev *dev = bus->self;
> -
> - if (pci_has_flag(PCI_PROBE_ONLY) && dev &&
> - (dev->class >> 8) == PCI_CLASS_BRIDGE_PCI) {
> - pci_read_bridge_bases(bus);
> - }
> + struct pci_dev *dev;
>
> list_for_each_entry(dev, &bus->devices, bus_list) {
> pdev_save_srm_config(dev);
> diff --git a/arch/frv/mb93090-mb00/pci-vdk.c b/arch/frv/mb93090-mb00/pci-vdk.c
> index f211839..f9c86c4 100644
> --- a/arch/frv/mb93090-mb00/pci-vdk.c
> +++ b/arch/frv/mb93090-mb00/pci-vdk.c
> @@ -294,8 +294,6 @@ void pcibios_fixup_bus(struct pci_bus *bus)
> printk("### PCIBIOS_FIXUP_BUS(%d)\n",bus->number);
> #endif
>
> - pci_read_bridge_bases(bus);
> -
> if (bus->number == 0) {
> struct pci_dev *dev;
> list_for_each_entry(dev, &bus->devices, bus_list) {
> diff --git a/arch/ia64/pci/pci.c b/arch/ia64/pci/pci.c
> index 7cc3be9..563228b 100644
> --- a/arch/ia64/pci/pci.c
> +++ b/arch/ia64/pci/pci.c
> @@ -534,7 +534,6 @@ void pcibios_fixup_bus(struct pci_bus *b)
> struct pci_dev *dev;
>
> if (b->self) {
> - pci_read_bridge_bases(b);
> pcibios_fixup_bridge_resources(b->self);
> }
> list_for_each_entry(dev, &b->devices, bus_list)
> diff --git a/arch/microblaze/pci/pci-common.c b/arch/microblaze/pci/pci-common.c
> index ae838ed..6b8b752 100644
> --- a/arch/microblaze/pci/pci-common.c
> +++ b/arch/microblaze/pci/pci-common.c
> @@ -863,14 +863,7 @@ void pcibios_setup_bus_devices(struct pci_bus *bus)
>
> void pcibios_fixup_bus(struct pci_bus *bus)
> {
> - /* When called from the generic PCI probe, read PCI<->PCI bridge
> - * bases. This is -not- called when generating the PCI tree from
> - * the OF device-tree.
> - */
> - if (bus->self != NULL)
> - pci_read_bridge_bases(bus);
> -
> - /* Now fixup the bus bus */
> + /* Fixup the bus */
> pcibios_setup_bus_self(bus);
>
> /* Now fixup devices on that bus */
> diff --git a/arch/mips/pci/pci.c b/arch/mips/pci/pci.c
> index b8a0bf5..c6996cf 100644
> --- a/arch/mips/pci/pci.c
> +++ b/arch/mips/pci/pci.c
> @@ -311,12 +311,6 @@ int pcibios_enable_device(struct pci_dev *dev, int mask)
>
> void pcibios_fixup_bus(struct pci_bus *bus)
> {
> - struct pci_dev *dev = bus->self;
> -
> - if (pci_has_flag(PCI_PROBE_ONLY) && dev &&
> - (dev->class >> 8) == PCI_CLASS_BRIDGE_PCI) {
> - pci_read_bridge_bases(bus);
> - }
> }
>
> EXPORT_SYMBOL(PCIBIOS_MIN_IO);
> diff --git a/arch/mn10300/unit-asb2305/pci.c b/arch/mn10300/unit-asb2305/pci.c
> index 3dfe2d3..deaa893 100644
> --- a/arch/mn10300/unit-asb2305/pci.c
> +++ b/arch/mn10300/unit-asb2305/pci.c
> @@ -324,7 +324,6 @@ void pcibios_fixup_bus(struct pci_bus *bus)
> struct pci_dev *dev;
>
> if (bus->self) {
> - pci_read_bridge_bases(bus);
> pcibios_fixup_bridge_resources(bus->self);
> }
>
> diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
> index 0d05406..722dd5f 100644
> --- a/arch/powerpc/kernel/pci-common.c
> +++ b/arch/powerpc/kernel/pci-common.c
> @@ -1043,13 +1043,7 @@ void pcibios_set_master(struct pci_dev *dev)
>
> void pcibios_fixup_bus(struct pci_bus *bus)
> {
> - /* When called from the generic PCI probe, read PCI<->PCI bridge
> - * bases. This is -not- called when generating the PCI tree from
> - * the OF device-tree.
> - */
> - pci_read_bridge_bases(bus);
> -
> - /* Now fixup the bus bus */
> + /* Fixup the bus */
> pcibios_setup_bus_self(bus);
>
> /* Now fixup devices on that bus */
> diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
> index 8fd6f44..3bff244 100644
> --- a/arch/x86/pci/common.c
> +++ b/arch/x86/pci/common.c
> @@ -166,7 +166,6 @@ void pcibios_fixup_bus(struct pci_bus *b)
> {
> struct pci_dev *dev;
>
> - pci_read_bridge_bases(b);
> list_for_each_entry(dev, &b->devices, bus_list)
> pcibios_fixup_device_resources(dev);
> }
> diff --git a/arch/xtensa/kernel/pci.c b/arch/xtensa/kernel/pci.c
> index b848cc3..d27b4dc 100644
> --- a/arch/xtensa/kernel/pci.c
> +++ b/arch/xtensa/kernel/pci.c
> @@ -210,10 +210,6 @@ subsys_initcall(pcibios_init);
>
> void pcibios_fixup_bus(struct pci_bus *bus)
> {
> - if (bus->parent) {
> - /* This is a subordinate bridge */
> - pci_read_bridge_bases(bus);
> - }
> }
>
> void pcibios_set_master(struct pci_dev *dev)
> diff --git a/drivers/parisc/dino.c b/drivers/parisc/dino.c
> index a0580af..baec33c 100644
> --- a/drivers/parisc/dino.c
> +++ b/drivers/parisc/dino.c
> @@ -560,9 +560,6 @@ dino_fixup_bus(struct pci_bus *bus)
> } else if (bus->parent) {
> int i;
>
> - pci_read_bridge_bases(bus);
> -
> -
> for(i = PCI_BRIDGE_RESOURCES; i < PCI_NUM_RESOURCES; i++) {
> if((bus->self->resource[i].flags &
> (IORESOURCE_IO | IORESOURCE_MEM)) == 0)
> diff --git a/drivers/parisc/lba_pci.c b/drivers/parisc/lba_pci.c
> index dceb9dd..901e1a3 100644
> --- a/drivers/parisc/lba_pci.c
> +++ b/drivers/parisc/lba_pci.c
> @@ -693,7 +693,6 @@ lba_fixup_bus(struct pci_bus *bus)
> if (bus->parent) {
> int i;
> /* PCI-PCI Bridge */
> - pci_read_bridge_bases(bus);
> for (i = PCI_BRIDGE_RESOURCES; i < PCI_NUM_RESOURCES; i++)
> pci_claim_bridge_resource(bus->self, i);
> } else {
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 6675a7a..1913e1b 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -332,6 +332,21 @@ static void pci_read_bases(struct pci_dev *dev, unsigned int howmany, int rom)
> }
> }
>
> +static void pci_claim_bridge_resources(struct pci_bus *bus)
> +{
> + struct pci_dev *dev = bus->self;
> + int idx;
> +
> + for (idx = PCI_BRIDGE_RESOURCES; idx < PCI_NUM_RESOURCES; idx++) {
> + struct resource *r = &dev->resource[idx];
> +
> + if (!r->flags || r->parent)
> + continue;
> +
> + pci_claim_bridge_resource(dev, idx);
> + }
> +}
> +
Nitpicking: Since pci_claim_bridge_resources() is small, and only called
once from pci_read_brdige_bases(), should we just put the loop inside
the function?
> static void pci_read_bridge_io(struct pci_bus *child)
> {
> struct pci_dev *dev = child->self;
> @@ -479,6 +494,8 @@ void pci_read_bridge_bases(struct pci_bus *child)
> }
> }
> }
> +
> + pci_claim_bridge_resources(child);
> }
>
> static struct pci_bus *pci_alloc_bus(struct pci_bus *parent)
> @@ -826,6 +843,11 @@ int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, int pass)
> child->bridge_ctl = bctl;
> }
>
> + /*
> + * Read and initialize bridge resources.
> + */
> + pci_read_bridge_bases(child);
> +
> cmax = pci_scan_child_bus(child);
> if (cmax > subordinate)
> dev_warn(&dev->dev, "bridge has subordinate %02x but max busn %02x\n",
> @@ -886,6 +908,10 @@ int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, int pass)
>
> if (!is_cardbus) {
> child->bridge_ctl = bctl;
> + /*
> + * Read and initialize bridge resources.
> + */
> + pci_read_bridge_bases(child);
> max = pci_scan_child_bus(child);
> } else {
> /*
>
--
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