[v7,08/10] PCI, x86: add MMCFG information on demand

Hi Yinghai,
	A formal patch to fix "here cache cfg too early.  should do 
that after pci_mmcfg_reject_broken()". This patch also improves
readability and fixes two condition compilation issues reported by
Fengguang. If you are ok with it, I will fold it into 
"[PATCH v7 08/10] PCI, x86: add MMCFG information on demand".
	Thanks!
	Gerry

---
---

On 2012-6-15 15:15, Yinghai Lu wrote:
> On Sat, May 26, 2012 at 2:54 AM, Jiang Liu <jiang.liu@huawei.com> wrote:
>> This patch changes mmconfig logic on x86 platforms to add MMCFG
>> information on demand instead of adding all MMCFG entries from
>> the ACPI MCFG table at boot time. So only MMCFG address ranges
>> used by active PCI host bridges will be actually mapped.
>>
>> Signed-off-by: Jiang Liu <liuj97@gmail.com>
>> ---
>>  arch/x86/include/asm/pci_x86.h |    5 +++
>>  arch/x86/pci/legacy.c          |    1 +
>>  arch/x86/pci/mmconfig-shared.c |   54 +++++++++++++++++++++++++++++++++++++---
>>  3 files changed, 56 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/pci_x86.h b/arch/x86/include/asm/pci_x86.h
>> index 3e5f43c..4a1a9aa 100644
>> --- a/arch/x86/include/asm/pci_x86.h
>> +++ b/arch/x86/include/asm/pci_x86.h
>> @@ -142,6 +142,11 @@ extern int __devinit pci_mmconfig_insert(struct device *dev,
>>                                         uint16_t seg, uint8_t start,
>>                                         uint8_t end, phys_addr_t addr);
>>  extern int pci_mmconfig_delete(uint16_t seg, uint8_t start, uint8_t end);
>> +#ifdef CONFIG_ACPI
>> +extern void pci_mmconfig_probe(uint8_t start);
>> +#else
>> +static inline void pci_mmconfig_probe(uint8_t start) { }
>> +#endif
>>  extern struct pci_mmcfg_region *pci_mmconfig_lookup(int segment, int bus);
>>
>>  extern struct list_head pci_mmcfg_list;
>> diff --git a/arch/x86/pci/legacy.c b/arch/x86/pci/legacy.c
>> index a1df191..e9a2384 100644
>> --- a/arch/x86/pci/legacy.c
>> +++ b/arch/x86/pci/legacy.c
>> @@ -49,6 +49,7 @@ void __devinit pcibios_scan_specific_bus(int busn)
>>                    l != 0x0000 && l != 0xffff) {
>>                        DBG("Found device at %02x:%02x [%04x]\n", busn, devfn, l);
>>                        printk(KERN_INFO "PCI: Discovered peer bus %02x\n", busn);
>> +                       pci_mmconfig_probe(busn);
>>                        pci_scan_bus_on_node(busn, &pci_root_ops, node);
>>                        return;
>>                }
>> diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
>> index fa0aa90..e80b5c2 100644
>> --- a/arch/x86/pci/mmconfig-shared.c
>> +++ b/arch/x86/pci/mmconfig-shared.c
>> @@ -19,6 +19,7 @@
>>  #include <linux/slab.h>
>>  #include <linux/mutex.h>
>>  #include <linux/rculist.h>
>> +#include <linux/pci-acpi.h>
>>  #include <asm/e820.h>
>>  #include <asm/pci_x86.h>
>>  #include <asm/acpi.h>
>> @@ -616,6 +617,16 @@ static int __init pci_parse_mcfg(struct acpi_table_header *header)
>>                        return -ENODEV;
>>                }
>>
>> +               /*
>> +                * MMCFG information for host brideges will be added on demand
>> +                * by pci_root driver if ACPI is enabled. But there are special
>> +                * requirements for devices on segment 0, MMCFG information may
>> +                * be needed for fixing hardware quirks and probing for hidden
>> +                * buses.
>> +                */
>> +               if (!acpi_disabled && cfg->pci_segment)
>> +                       continue;
>> +
>>                if (pci_mmconfig_add(cfg->pci_segment, cfg->start_bus_number,
>>                                   cfg->end_bus_number, cfg->address) == NULL) {
>>                        printk(KERN_WARNING PREFIX
>> @@ -625,6 +636,13 @@ static int __init pci_parse_mcfg(struct acpi_table_header *header)
>>                }
>>        }
>>
>> +       i = entries * sizeof(*cfg_table);
>> +       pci_acpi_mcfg_array = kmalloc(i, GFP_KERNEL);
>> +       if (pci_acpi_mcfg_array) {
>> +               memcpy(pci_acpi_mcfg_array, cfg_table, i);
>> +               pci_acpi_mcfg_entries = entries;
>> +       }
>> +
> 
> here cache cfg too early.  should do that after
> 
> pci_mmcfg_reject_broken().
> 
> otherwise will use mcfg even try to reject that before.
> 
>>        return 0;
>>  }
>>
>> @@ -634,14 +652,14 @@ static void __init __pci_mmcfg_init(int early)
>>        if ((pci_probe & PCI_PROBE_MMCONF) == 0)
>>                return;
>>
>> -       /* MMCONFIG already enabled */
>> -       if (!early && !(pci_probe & PCI_PROBE_MASK & ~PCI_PROBE_MMCONF))
>> -               return;
>> -
>>        /* for late to exit */
>>        if (known_bridge)
>>                return;
>>
>> +       /* MMCONFIG already enabled */
>> +       if (!early && !(pci_probe & PCI_PROBE_MASK & ~PCI_PROBE_MMCONF))
>> +               goto out;
>> +
>>        if (early) {
>>                if (pci_mmcfg_check_hostbridge())
>>                        known_bridge = 1;
>> @@ -675,6 +693,14 @@ static void __init __pci_mmcfg_init(int early)
>>                pci_mmcfg_resources_inserted = 1;
>>                pci_mmcfg_arch_init_failed = true;
>>        }
>> +
>> +out:
>> +       /*
>> +        * Free all MCFG entries if ACPI is enabled. MCFG information will
>> +        * be added back on demand by the pci_root driver later.
>> +        */
>> +       if (!early && !acpi_disabled && !known_bridge && pci_acpi_mcfg_array)
>> +               free_all_mmcfg();
> 
> that really change the logic.
> 
> looks like it will break mrst/sfi path.
> 
> the scan from pci_legacy_init() for mrst/sfi will not have ext_pci_ops
> set for bus 0.
> 
> | int __init pci_subsys_init(void)
> | {
> |        /*
> |         * The init function returns an non zero value when
> |         * pci_legacy_init should be invoked.
> |         */
> |        if (x86_init.pci.init())
> |                pci_legacy_init();
> |
> |        pcibios_fixup_peer_bridges();
> 
> 
> Yinghai
> 
>>  }
>>
>>  void __init pci_mmcfg_early_init(void)
>> @@ -809,3 +835,23 @@ int pci_mmconfig_delete(uint16_t seg, uint8_t start, uint8_t end)
>>
>>        return -ENOENT;
>>  }
>> +
>> +/* Probe MMCFG information for PCI bus blind probe */
>> +void __devinit pci_mmconfig_probe(uint8_t start)
>> +{
>> +       int end_bus, temp;
>> +       phys_addr_t addr;
>> +
>> +       if (!(pci_probe & PCI_PROBE_MMCONF) || pci_mmcfg_arch_init_failed)
>> +               return;
>> +
>> +       addr = acpi_pci_root_get_mcfg_addr(NULL, 0, start, &end_bus);
>> +       if (addr && end_bus >= 0 && end_bus <= 255) {
>> +               for (temp = start + 1; temp <= end_bus; temp++)
>> +                       if (pci_find_bus(0, temp))
>> +                               break;
>> +
>> +               temp--;
>> +               pci_mmconfig_insert(NULL, 0, start, (uint8_t)temp, addr);
>> +       }
>> +}
>> --
>> 1.7.1
>>
>>
> 
> .
> 


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[v7,08/10] PCI, x86: add MMCFG information on demand

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