Re: [PATCH v7 3/3] arm64: Add architecture support for PCI

[Liviu Dudau <Liviu.Dudau-5wv7dgnIgG8@public.gmane.org>]

On Tue, Apr 08, 2014 at 12:58:30AM +0100, Bjorn Helgaas wrote:
> On Fri, Mar 14, 2014 at 03:34:18PM +0000, Liviu Dudau wrote:
> > Use the generic host bridge functions to provide support for
> > PCI Express on arm64. There is no support for ISA memory.
> >
> > Signed-off-by: Liviu Dudau <Liviu.Dudau-5wv7dgnIgG8@public.gmane.org>
> > Tested-by: Tanmay Inamdar <tinamdar-qTEPVZfXA3Y@public.gmane.org>
> > ---
> >  arch/arm64/Kconfig            |  19 +++-
> >  arch/arm64/include/asm/Kbuild |   1 +
> >  arch/arm64/include/asm/io.h   |   3 +-
> >  arch/arm64/include/asm/pci.h  |  51 ++++++++++
> >  arch/arm64/kernel/Makefile    |   1 +
> >  arch/arm64/kernel/pci.c       | 173 ++++++++++++++++++++++++++++++++
> >  6 files changed, 246 insertions(+), 2 deletions(-)
> >  create mode 100644 arch/arm64/include/asm/pci.h
> >  create mode 100644 arch/arm64/kernel/pci.c
> >
> > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> > index 27bbcfc..d1c8568 100644
> > --- a/arch/arm64/Kconfig
> > +++ b/arch/arm64/Kconfig
> > @@ -62,7 +62,7 @@ config MMU
> >       def_bool y
> >
> >  config NO_IOPORT
> > -     def_bool y
> > +     def_bool y if !PCI
> >
> >  config STACKTRACE_SUPPORT
> >       def_bool y
> > @@ -134,6 +134,23 @@ menu "Bus support"
> >  config ARM_AMBA
> >       bool
> >
> > +config PCI
> > +     bool "PCI support"
> > +     help
> > +       This feature enables support for PCIe bus system. If you say Y
> > +       here, the kernel will include drivers and infrastructure code
> > +       to support PCIe bus devices.
> > +
> > +config PCI_DOMAINS
> > +     def_bool PCI
> > +
> > +config PCI_SYSCALL
> > +     def_bool PCI
> > +
> > +source "drivers/pci/Kconfig"
> > +source "drivers/pci/pcie/Kconfig"
> > +source "drivers/pci/hotplug/Kconfig"
> > +
> >  endmenu
> >
> >  menu "Kernel Features"
> > diff --git a/arch/arm64/include/asm/Kbuild b/arch/arm64/include/asm/Kbuild
> > index 71c53ec..46924bc 100644
> > --- a/arch/arm64/include/asm/Kbuild
> > +++ b/arch/arm64/include/asm/Kbuild
> > @@ -26,6 +26,7 @@ generic-y += mman.h
> >  generic-y += msgbuf.h
> >  generic-y += mutex.h
> >  generic-y += pci.h
> > +generic-y += pci-bridge.h
> >  generic-y += poll.h
> >  generic-y += posix_types.h
> >  generic-y += resource.h
> > diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h
> > index 7846a6b..67463a5 100644
> > --- a/arch/arm64/include/asm/io.h
> > +++ b/arch/arm64/include/asm/io.h
> > @@ -120,7 +120,8 @@ static inline u64 __raw_readq(const volatile void __iomem *addr)
> >  /*
> >   *  I/O port access primitives.
> >   */
> > -#define IO_SPACE_LIMIT               0xffff
> > +#define arch_has_dev_port()  (1)
> > +#define IO_SPACE_LIMIT               0x1ffffff
> >  #define PCI_IOBASE           ((void __iomem *)(MODULES_VADDR - SZ_32M))
> >
> >  static inline u8 inb(unsigned long addr)
> > diff --git a/arch/arm64/include/asm/pci.h b/arch/arm64/include/asm/pci.h
> > new file mode 100644
> > index 0000000..d93576f
> > --- /dev/null
> > +++ b/arch/arm64/include/asm/pci.h
> > @@ -0,0 +1,51 @@
> > +#ifndef __ASM_PCI_H
> > +#define __ASM_PCI_H
> > +#ifdef __KERNEL__
> > +
> > +#include <linux/types.h>
> > +#include <linux/slab.h>
> > +#include <linux/dma-mapping.h>
> > +
> > +#include <asm/io.h>
> > +#include <asm-generic/pci-bridge.h>
> > +#include <asm-generic/pci-dma-compat.h>
> > +
> > +#define PCIBIOS_MIN_IO               0x1000
> > +#define PCIBIOS_MIN_MEM              0
> > +
> > +struct pci_host_bridge *find_pci_host_bridge(struct pci_bus *bus);
> > +
> > +/*
> > + * Set to 1 if the kernel should re-assign all PCI bus numbers
> > + */
> > +#define pcibios_assign_all_busses() \
> > +     (pci_has_flag(PCI_REASSIGN_ALL_BUS))
> > +
> > +/*
> > + * PCI address space differs from physical memory address space
> > + */
> > +#define PCI_DMA_BUS_IS_PHYS  (0)
> > +
> > +extern int isa_dma_bridge_buggy;
> > +
> > +#ifdef CONFIG_PCI
> > +static inline int pci_domain_nr(struct pci_bus *bus)
> > +{
> > +     struct pci_host_bridge *bridge = find_pci_host_bridge(bus);
> > +
> > +     if (bridge)
> > +             return bridge->domain_nr;
> > +
> > +     return 0;
> > +}
> > +
> > +static inline int pci_proc_domain(struct pci_bus *bus)
> > +{
> > +     return 1;
> > +}
> > +#endif
> > +
> > +extern unsigned long pci_ioremap_io(const struct resource *res, phys_addr_t phys_addr);
> > +
> > +#endif  /* __KERNEL__ */
> > +#endif  /* __ASM_PCI_H */
> > diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
> > index 2d4554b..64fc479 100644
> > --- a/arch/arm64/kernel/Makefile
> > +++ b/arch/arm64/kernel/Makefile
> > @@ -20,6 +20,7 @@ arm64-obj-$(CONFIG_HAVE_HW_BREAKPOINT)+= hw_breakpoint.o
> >  arm64-obj-$(CONFIG_EARLY_PRINTK)     += early_printk.o
> >  arm64-obj-$(CONFIG_ARM64_CPU_SUSPEND)        += sleep.o suspend.o
> >  arm64-obj-$(CONFIG_JUMP_LABEL)               += jump_label.o
> > +arm64-obj-$(CONFIG_PCI)                      += pci.o
> >
> >  obj-y                                        += $(arm64-obj-y) vdso/
> >  obj-m                                        += $(arm64-obj-m)
> > diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c
> > new file mode 100644
> > index 0000000..9f29c9a
> > --- /dev/null
> > +++ b/arch/arm64/kernel/pci.c
> > @@ -0,0 +1,173 @@
> > +/*
> > + * Code borrowed from powerpc/kernel/pci-common.c
> > + *
> > + * Copyright (C) 2003 Anton Blanchard <anton-hXjcm30GF6XQT0dZR+AlfA@public.gmane.org>, IBM
> > + * Copyright (C) 2014 ARM Ltd.
> > + *
> > + * 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.
> > + *
> > + */
> > +
> > +#include <linux/init.h>
> > +#include <linux/io.h>
> > +#include <linux/kernel.h>
> > +#include <linux/mm.h>
> > +#include <linux/of_pci.h>
> > +#include <linux/of_platform.h>
> > +#include <linux/slab.h>
> > +
> > +#include <asm/pci-bridge.h>
> > +
> > +struct ioresource {
> > +     struct list_head list;
> > +     phys_addr_t start;
> > +     resource_size_t size;
> > +};
> > +
> > +static LIST_HEAD(io_list);
> > +
> > +int pci_register_io_range(phys_addr_t address, resource_size_t size)
> > +{
> > +     struct ioresource *res;
> > +     resource_size_t allocated_size = 0;
> > +
> > +     /* find if the range has not been already allocated */
> > +     list_for_each_entry(res, &io_list, list) {
> > +             if (address >= res->start &&
> > +                     address + size <= res->start + size)
> > +                     return 0;
> > +             allocated_size += res->size;
> > +     }
> > +
> > +     /* range not already registered, check for space */
> > +     if (allocated_size + size > IO_SPACE_LIMIT)
> > +             return -E2BIG;
> > +
> > +     /* add the range in the list */
> > +     res = kzalloc(sizeof(*res), GFP_KERNEL);
> > +     if (!res)
> > +             return -ENOMEM;
> > +     res->start = address;
> > +     res->size = size;
> > +
> > +     list_add_tail(&res->list, &io_list);
> > +
> > +     return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(pci_register_io_range);
> > +
> > +unsigned long pci_address_to_pio(phys_addr_t address)
> > +{
> > +     struct ioresource *res;
> > +
> > +     list_for_each_entry(res, &io_list, list) {
> > +             if (address >= res->start &&
> > +                     address < res->start + res->size) {
> > +                     return res->start - address;
> > +             }
> > +     }
> > +
> > +     return (unsigned long)-1;
> > +}
> > +EXPORT_SYMBOL_GPL(pci_address_to_pio);
> > +
> > +/*
> > + * Called after each bus is probed, but before its children are examined
> > + */
> > +void pcibios_fixup_bus(struct pci_bus *bus)
> > +{
> > +     struct pci_dev *dev;
> > +     struct resource *res;
> > +     int i;
> > +
> > +     if (!pci_is_root_bus(bus)) {
> > +             pci_read_bridge_bases(bus);
> > +
> > +             pci_bus_for_each_resource(bus, res, i) {
> > +                     if (!res || !res->flags || res->parent)
> > +                             continue;
> > +
> > +                     /*
> > +                      * If we are going to reassign everything, we can
> > +                      * shrink the P2P resource to have zero size to
> > +                      * save space
> > +                      */
> > +                     if (pci_has_flag(PCI_REASSIGN_ALL_RSRC)) {
> > +                             res->flags |= IORESOURCE_UNSET;
> > +                             res->start = 0;
> > +                             res->end = -1;
> > +                             continue;
> > +                     }
> > +             }
> > +     }
> 
> Is there any other place we can put this?  I'm trying to nuke
> pcibios_fixup_bus() because things like hotplug work better if we can do
> them in a per-device way rather than a per-bus way.

That's good. I'm all for removing this one, will give it a go.

> 
> > +
> > +     list_for_each_entry(dev, &bus->devices, bus_list) {
> > +             /* Ignore fully discovered devices */
> > +             if (dev->is_added)
> > +                     continue;
> > +
> > +             set_dev_node(&dev->dev, pcibus_to_node(dev->bus));
> 
> Do you really need this?  pci_device_add() already contains the same line.

OK.

> 
> > +
> > +             /* Read default IRQs and fixup if necessary */
> > +             dev->irq = of_irq_parse_and_map_pci(dev, 0, 0);
> 
> Could this be done in pcibios_add_device() or someplace similar?

Will do.

> 
> > +     }
> > +}
> > +EXPORT_SYMBOL(pcibios_fixup_bus);
> > +
> > +/*
> > + * We don't have to worry about legacy ISA devices, so nothing to do here
> > + */
> > +resource_size_t pcibios_align_resource(void *data, const struct resource *res,
> > +                             resource_size_t size, resource_size_t align)
> > +{
> > +     return res->start;
> > +}
> > +
> > +int pcibios_enable_device(struct pci_dev *dev, int mask)
> > +{
> > +     return pci_enable_resources(dev, mask);
> > +}
> 
> There is already a weak default implementation of pcibios_enable_device()
> that does this, so you should be able to just drop this.

OK.

Thanks for reviewing the series!

Liviu

> 
> > +#define IO_SPACE_PAGES       ((IO_SPACE_LIMIT + 1) / PAGE_SIZE)
> > +static DECLARE_BITMAP(pci_iospace, IO_SPACE_PAGES);
> > +
> > +unsigned long pci_ioremap_io(const struct resource *res, phys_addr_t phys_addr)
> > +{
> > +     unsigned long start, len, virt_start;
> > +     int err;
> > +
> > +     if (res->end > IO_SPACE_LIMIT)
> > +             return -EINVAL;
> > +
> > +     /*
> > +      * try finding free space for the whole size first,
> > +      * fall back to 64K if not available
> > +      */
> > +     len = resource_size(res);
> > +     start = bitmap_find_next_zero_area(pci_iospace, IO_SPACE_PAGES,
> > +                             res->start / PAGE_SIZE, len / PAGE_SIZE, 0);
> > +     if (start == IO_SPACE_PAGES && len > SZ_64K) {
> > +             len = SZ_64K;
> > +             start = 0;
> > +             start = bitmap_find_next_zero_area(pci_iospace, IO_SPACE_PAGES,
> > +                                     start, len / PAGE_SIZE, 0);
> > +     }
> > +
> > +     /* no 64K area found */
> > +     if (start == IO_SPACE_PAGES)
> > +             return -ENOMEM;
> > +
> > +     /* ioremap physical aperture to virtual aperture */
> > +     virt_start = start * PAGE_SIZE + (unsigned long)PCI_IOBASE;
> > +     err = ioremap_page_range(virt_start, virt_start + len,
> > +                             phys_addr, __pgprot(PROT_DEVICE_nGnRE));
> > +     if (err)
> > +             return err;
> > +
> > +     bitmap_set(pci_iospace, start, len / PAGE_SIZE);
> > +
> > +     /* return io_offset */
> > +     return start * PAGE_SIZE - res->start;
> > +}
> > --
> > 1.9.0
> >
> 

-- 
====================
| I would like to |
| fix the world,  |
| but they're not |
| giving me the   |
 \ source code!  /
  ---------------
    ¯\_(ツ)_/¯

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