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Message-ID: <573DF039.5040405@suse.com>
Date: Thu, 19 May 2016 18:56:25 +0200
From: Matthias Brugger <mbrugger@...e.com>
To: Tomasz Nowicki <tn@...ihalf.com>, helgaas@...nel.org,
arnd@...db.de, will.deacon@....com, catalin.marinas@....com,
rafael@...nel.org, hanjun.guo@...aro.org,
Lorenzo.Pieralisi@....com, okaya@...eaurora.org,
jchandra@...adcom.com
Cc: jcm@...hat.com, linaro-acpi@...ts.linaro.org,
linux-pci@...r.kernel.org, dhdang@....com, Liviu.Dudau@....com,
ddaney@...iumnetworks.com, jeremy.linton@....com,
linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
robert.richter@...iumnetworks.com, cov@...eaurora.org,
Suravee.Suthikulpanit@....com, msalter@...hat.com,
wangyijing@...wei.com, mw@...ihalf.com, andrea.gallo@...aro.org,
linux-arm-kernel@...ts.infradead.org, liudongdong3@...wei.com
Subject: Re: [PATCH V7 08/11] pci, acpi: Support for ACPI based generic PCI
host controller
On 10/05/16 17:19, Tomasz Nowicki 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@...ihalf.com>
> Signed-off-by: Jayachandran C <jchandra@...adcom.com>
> ---
> drivers/acpi/Kconfig | 8 +++
> drivers/acpi/Makefile | 1 +
> drivers/acpi/pci_mcfg.c | 97 ++++++++++++++++++++++++++
> drivers/acpi/pci_root_generic.c | 149 ++++++++++++++++++++++++++++++++++++++++
> drivers/pci/ecam.h | 5 ++
> include/linux/pci-acpi.h | 5 ++
> include/linux/pci.h | 5 +-
> 7 files changed, 269 insertions(+), 1 deletion(-)
> create mode 100644 drivers/acpi/pci_mcfg.c
> create mode 100644 drivers/acpi/pci_root_generic.c
>
> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
> index 183ffa3..44afc76 100644
> --- a/drivers/acpi/Kconfig
> +++ b/drivers/acpi/Kconfig
> @@ -346,6 +346,14 @@ config ACPI_PCI_SLOT
> i.e., segment/bus/device/function tuples, with physical slots in
> the system. If you are unsure, say N.
>
> +config ACPI_PCI_HOST_GENERIC
> + bool
> + select PCI_ECAM
> + help
> + Select this config option from the architecture Kconfig,
> + if it is preferred to enable ACPI PCI host controller driver which
> + has no arch-specific assumptions.
> +
> config X86_PM_TIMER
> bool "Power Management Timer Support" if EXPERT
> depends on X86
> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> index 81e5cbc..627a2b7 100644
> --- a/drivers/acpi/Makefile
> +++ b/drivers/acpi/Makefile
> @@ -40,6 +40,7 @@ acpi-$(CONFIG_ARCH_MIGHT_HAVE_ACPI_PDC) += processor_pdc.o
> acpi-y += ec.o
> acpi-$(CONFIG_ACPI_DOCK) += dock.o
> acpi-y += pci_root.o pci_link.o pci_irq.o
> +obj-$(CONFIG_ACPI_PCI_HOST_GENERIC) += pci_root_generic.o pci_mcfg.o
> acpi-y += acpi_lpss.o acpi_apd.o
> acpi-y += acpi_platform.o
> acpi-y += acpi_pnp.o
> diff --git a/drivers/acpi/pci_mcfg.c b/drivers/acpi/pci_mcfg.c
> new file mode 100644
> index 0000000..373d079
> --- /dev/null
> +++ b/drivers/acpi/pci_mcfg.c
> @@ -0,0 +1,97 @@
> +/*
> + * Copyright (C) 2016 Broadcom
> + * Author: Jayachandran C <jchandra@...adcom.com>
> + * Copyright (C) 2016 Semihalf
> + * Author: Tomasz Nowicki <tn@...ihalf.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License, version 2, as
> + * published by the Free Software Foundation (the "GPL").
> + *
> + * This program is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * General Public License version 2 (GPLv2) for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * version 2 (GPLv2) along with this source code.
> + */
> +#include <linux/kernel.h>
> +#include <linux/pci.h>
> +#include <linux/pci-acpi.h>
> +
> +#define PREFIX "ACPI: "
> +
> +/* Root pointer to the mapped MCFG table */
> +static struct acpi_table_mcfg *mcfg_table;
> +
> +#define MCFG_ENTRIES(mcfg_ptr) (((mcfg_ptr)->header.length - \
> + sizeof(struct acpi_table_mcfg)) / \
> + sizeof(struct acpi_mcfg_allocation))
> +
> +static phys_addr_t pci_mcfg_lookup_static(u16 seg, u8 bus_start, u8 bus_end)
> +{
> + struct acpi_mcfg_allocation *mptr;
> + int i;
> +
> + if (!mcfg_table) {
> + pr_err(PREFIX "MCFG table not available, lookup failed\n");
> + return -ENXIO;
> + }
> +
> + mptr = (struct acpi_mcfg_allocation *) &mcfg_table[1];
> +
> + /*
> + * We expect exact match, unless MCFG entry end bus covers more than
> + * specified by caller.
> + */
> + for (i = 0; i < MCFG_ENTRIES(mcfg_table); i++, mptr++) {
> + if (mptr->pci_segment == seg &&
> + mptr->start_bus_number == bus_start &&
> + mptr->end_bus_number >= bus_end) {
> + return mptr->address;
> + }
> + }
> +
> + return -ENXIO;
> +}
> +
> +phys_addr_t pci_mcfg_lookup(struct acpi_device *device, u16 seg,
> + struct resource *bus_res)
> +{
> + phys_addr_t addr;
> +
> + addr = acpi_pci_root_get_mcfg_addr(device->handle);
> + if (addr)
> + return addr;
> +
> + return pci_mcfg_lookup_static(seg, bus_res->start, bus_res->end);
> +}
> +
> +static __init int pci_mcfg_parse(struct acpi_table_header *header)
> +{
> + struct acpi_table_mcfg *mcfg;
> + int n;
> +
> + if (!header)
> + return -EINVAL;
Maybe that's bike shedding, but acpi_table_parse already checks that the
table passed to the handler exists, so this is redundant.
Regards,
Matthias
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