Re: [PATCH v3] Add NumaChip remote PCI support

[Bjorn Helgaas]

On Tue, Dec 4, 2012 at 2:56 AM, Daniel J Blueman
<daniel@xxxxxxxxxxxxxxxxxx> wrote:
> Add NumaChip-specific PCI access mechanism via MMCONFIG cycles, but
> preventing access to AMD Northbridges which shouldn't respond.
>
> v2: Use PCI_DEVFN in precomputed constant limit; drop unneeded includes
> v3: Express dependency on MMCONFIG
>
> Signed-off-by: Daniel J Blueman <daniel@xxxxxxxxxxxxxxxxxx>

I applied this to my -next branch, headed for v3.8.

Thanks!

> ---
>  arch/x86/Kconfig                         |    2 +
>  arch/x86/include/asm/numachip/numachip.h |   20 +++++
>  arch/x86/kernel/apic/apic_numachip.c     |    2 +
>  arch/x86/pci/Makefile                    |    1 +
>  arch/x86/pci/numachip.c                  |  129 ++++++++++++++++++++++++++++++
>  5 files changed, 154 insertions(+)
>  create mode 100644 arch/x86/include/asm/numachip/numachip.h
>  create mode 100644 arch/x86/pci/numachip.c
>
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 46c3bff..50e8700 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -374,6 +374,7 @@ config X86_NUMACHIP
>         depends on NUMA
>         depends on SMP
>         depends on X86_X2APIC
> +       depends on PCI_MMCONFIG
>         ---help---
>           Adds support for Numascale NumaChip large-SMP systems. Needed to
>           enable more than ~168 cores.
> diff --git a/arch/x86/include/asm/numachip/numachip.h b/arch/x86/include/asm/numachip/numachip.h
> new file mode 100644
> index 0000000..fe7f60c
> --- /dev/null
> +++ b/arch/x86/include/asm/numachip/numachip.h
> @@ -0,0 +1,20 @@
> +/*
> + * This file is subject to the terms and conditions of the GNU General Public
> + * License.  See the file "COPYING" in the main directory of this archive
> + * for more details.
> + *
> + * Numascale NumaConnect-specific header file
> + *
> + * Copyright (C) 2012 Numascale AS. All rights reserved.
> + *
> + * Send feedback to <support@xxxxxxxxxxxxx>
> + *
> + */
> +
> +#ifndef _ASM_X86_NUMACHIP_NUMACHIP_H
> +#define _ASM_X86_NUMACHIP_NUMACHIP_H
> +
> +extern int __init pci_numachip_init(void);
> +
> +#endif /* _ASM_X86_NUMACHIP_NUMACHIP_H */
> +
> diff --git a/arch/x86/kernel/apic/apic_numachip.c b/arch/x86/kernel/apic/apic_numachip.c
> index a65829a..9c2aa89 100644
> --- a/arch/x86/kernel/apic/apic_numachip.c
> +++ b/arch/x86/kernel/apic/apic_numachip.c
> @@ -22,6 +22,7 @@
>  #include <linux/hardirq.h>
>  #include <linux/delay.h>
>
> +#include <asm/numachip/numachip.h>
>  #include <asm/numachip/numachip_csr.h>
>  #include <asm/smp.h>
>  #include <asm/apic.h>
> @@ -179,6 +180,7 @@ static int __init numachip_system_init(void)
>                 return 0;
>
>         x86_cpuinit.fixup_cpu_id = fixup_cpu_id;
> +       x86_init.pci.arch_init = pci_numachip_init;
>
>         map_csrs();
>
> diff --git a/arch/x86/pci/Makefile b/arch/x86/pci/Makefile
> index 3af5a1e..ee0af58 100644
> --- a/arch/x86/pci/Makefile
> +++ b/arch/x86/pci/Makefile
> @@ -16,6 +16,7 @@ obj-$(CONFIG_STA2X11)           += sta2x11-fixup.o
>  obj-$(CONFIG_X86_VISWS)                += visws.o
>
>  obj-$(CONFIG_X86_NUMAQ)                += numaq_32.o
> +obj-$(CONFIG_X86_NUMACHIP)     += numachip.o
>
>  obj-$(CONFIG_X86_INTEL_MID)    += mrst.o
>
> diff --git a/arch/x86/pci/numachip.c b/arch/x86/pci/numachip.c
> new file mode 100644
> index 0000000..7307d9d
> --- /dev/null
> +++ b/arch/x86/pci/numachip.c
> @@ -0,0 +1,129 @@
> +/*
> + * This file is subject to the terms and conditions of the GNU General Public
> + * License.  See the file "COPYING" in the main directory of this archive
> + * for more details.
> + *
> + * Numascale NumaConnect-specific PCI code
> + *
> + * Copyright (C) 2012 Numascale AS. All rights reserved.
> + *
> + * Send feedback to <support@xxxxxxxxxxxxx>
> + *
> + * PCI accessor functions derived from mmconfig_64.c
> + *
> + */
> +
> +#include <linux/pci.h>
> +#include <asm/pci_x86.h>
> +
> +static u8 limit __read_mostly;
> +
> +static inline char __iomem *pci_dev_base(unsigned int seg, unsigned int bus, unsigned int devfn)
> +{
> +       struct pci_mmcfg_region *cfg = pci_mmconfig_lookup(seg, bus);
> +
> +       if (cfg && cfg->virt)
> +               return cfg->virt + (PCI_MMCFG_BUS_OFFSET(bus) | (devfn << 12));
> +       return NULL;
> +}
> +
> +static int pci_mmcfg_read_numachip(unsigned int seg, unsigned int bus,
> +                         unsigned int devfn, int reg, int len, u32 *value)
> +{
> +       char __iomem *addr;
> +
> +       /* Why do we have this when nobody checks it. How about a BUG()!? -AK */
> +       if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) {
> +err:           *value = -1;
> +               return -EINVAL;
> +       }
> +
> +       /* Ensure AMD Northbridges don't decode reads to other devices */
> +       if (unlikely(bus == 0 && devfn >= limit)) {
> +               *value = -1;
> +               return 0;
> +       }
> +
> +       rcu_read_lock();
> +       addr = pci_dev_base(seg, bus, devfn);
> +       if (!addr) {
> +               rcu_read_unlock();
> +               goto err;
> +       }
> +
> +       switch (len) {
> +       case 1:
> +               *value = mmio_config_readb(addr + reg);
> +               break;
> +       case 2:
> +               *value = mmio_config_readw(addr + reg);
> +               break;
> +       case 4:
> +               *value = mmio_config_readl(addr + reg);
> +               break;
> +       }
> +       rcu_read_unlock();
> +
> +       return 0;
> +}
> +
> +static int pci_mmcfg_write_numachip(unsigned int seg, unsigned int bus,
> +                          unsigned int devfn, int reg, int len, u32 value)
> +{
> +       char __iomem *addr;
> +
> +       /* Why do we have this when nobody checks it. How about a BUG()!? -AK */
> +       if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095)))
> +               return -EINVAL;
> +
> +       /* Ensure AMD Northbridges don't decode writes to other devices */
> +       if (unlikely(bus == 0 && devfn >= limit))
> +               return 0;
> +
> +       rcu_read_lock();
> +       addr = pci_dev_base(seg, bus, devfn);
> +       if (!addr) {
> +               rcu_read_unlock();
> +               return -EINVAL;
> +       }
> +
> +       switch (len) {
> +       case 1:
> +               mmio_config_writeb(addr + reg, value);
> +               break;
> +       case 2:
> +               mmio_config_writew(addr + reg, value);
> +               break;
> +       case 4:
> +               mmio_config_writel(addr + reg, value);
> +               break;
> +       }
> +       rcu_read_unlock();
> +
> +       return 0;
> +}
> +
> +const struct pci_raw_ops pci_mmcfg_numachip = {
> +       .read = pci_mmcfg_read_numachip,
> +       .write = pci_mmcfg_write_numachip,
> +};
> +
> +int __init pci_numachip_init(void)
> +{
> +       int ret = 0;
> +       u32 val;
> +
> +       /* For remote I/O, restrict bus 0 access to the actual number of AMD
> +          Northbridges, which starts at device number 0x18 */
> +       ret = raw_pci_read(0, 0, PCI_DEVFN(0x18, 0), 0x60, sizeof(val), &val);
> +       if (ret)
> +               goto out;
> +
> +       /* HyperTransport fabric size in bits 6:4 */
> +       limit = PCI_DEVFN(0x18 + ((val >> 4) & 7) + 1, 0);
> +
> +       /* Use NumaChip PCI accessors for non-extended and extended access */
> +       raw_pci_ops = raw_pci_ext_ops = &pci_mmcfg_numachip;
> +out:
> +       return ret;
> +}
> --
> 1.7.10.4
>
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