From 46b304934de417a2238d659ef6459a74cb3f5e6b Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Sat, 10 Jun 2006 01:06:25 -0700 Subject: [PATCH] [SPARC64]: Avoid JBUS errors on some Niagara systems. Doing PCI config space accesses to non-present PCI slots can result in fatal JBUS errors if the PCI config access hypervisor call is performed on cpus other than the boot cpu. PCI config space accesses to present PCI slots works just fine. Recursively traverse the OBP device tree under the PCI controller node and record all present device IDs into a small hash table. Avoid the hypervisor call for any PCI config space access attempt for a device not recorded in the hash table. Signed-off-by: David S. Miller --- arch/sparc64/kernel/pci_sun4v.c | 124 ++++++++++++++++++++++++++++++-- 1 file changed, 118 insertions(+), 6 deletions(-) diff --git a/arch/sparc64/kernel/pci_sun4v.c b/arch/sparc64/kernel/pci_sun4v.c index 2b7a1f316a93..0c0895202970 100644 --- a/arch/sparc64/kernel/pci_sun4v.c +++ b/arch/sparc64/kernel/pci_sun4v.c @@ -599,18 +599,128 @@ struct pci_iommu_ops pci_sun4v_iommu_ops = { /* SUN4V PCI configuration space accessors. */ -static inline int pci_sun4v_out_of_range(struct pci_pbm_info *pbm, unsigned int bus, unsigned int device, unsigned int func) +struct pdev_entry { + struct pdev_entry *next; + u32 devhandle; + unsigned int bus; + unsigned int device; + unsigned int func; +}; + +#define PDEV_HTAB_SIZE 16 +#define PDEV_HTAB_MASK (PDEV_HTAB_SIZE - 1) +static struct pdev_entry *pdev_htab[PDEV_HTAB_SIZE]; + +static inline unsigned int pdev_hashfn(u32 devhandle, unsigned int bus, unsigned int device, unsigned int func) { - if (bus == pbm->pci_first_busno) { - if (device == 0 && func == 0) - return 0; - return 1; + unsigned int val; + + val = (devhandle ^ (devhandle >> 4)); + val ^= bus; + val ^= device; + val ^= func; + + return val & PDEV_HTAB_MASK; +} + +static int pdev_htab_add(u32 devhandle, unsigned int bus, unsigned int device, unsigned int func) +{ + struct pdev_entry *p = kmalloc(sizeof(*p), GFP_KERNEL); + struct pdev_entry **slot; + + if (!p) + return -ENOMEM; + + slot = &pdev_htab[pdev_hashfn(devhandle, bus, device, func)]; + p->next = *slot; + *slot = p; + + p->devhandle = devhandle; + p->bus = bus; + p->device = device; + p->func = func; + + return 0; +} + +/* Recursively descend into the OBP device tree, rooted at toplevel_node, + * looking for a PCI device matching bus and devfn. + */ +static int obp_find(struct linux_prom_pci_registers *pregs, int toplevel_node, unsigned int bus, unsigned int devfn) +{ + toplevel_node = prom_getchild(toplevel_node); + + while (toplevel_node != 0) { + int ret = obp_find(pregs, toplevel_node, bus, devfn); + + if (ret != 0) + return ret; + + ret = prom_getproperty(toplevel_node, "reg", (char *) pregs, + sizeof(*pregs) * PROMREG_MAX); + if (ret == 0 || ret == -1) + goto next_sibling; + + if (((pregs[0].phys_hi >> 16) & 0xff) == bus && + ((pregs[0].phys_hi >> 8) & 0xff) == devfn) + break; + + next_sibling: + toplevel_node = prom_getsibling(toplevel_node); + } + + return toplevel_node; +} + +static int pdev_htab_populate(struct pci_pbm_info *pbm) +{ + struct linux_prom_pci_registers pr[PROMREG_MAX]; + u32 devhandle = pbm->devhandle; + unsigned int bus; + + for (bus = pbm->pci_first_busno; bus <= pbm->pci_last_busno; bus++) { + unsigned int devfn; + + for (devfn = 0; devfn < 256; devfn++) { + unsigned int device = PCI_SLOT(devfn); + unsigned int func = PCI_FUNC(devfn); + + if (obp_find(pr, pbm->prom_node, bus, devfn)) { + int err = pdev_htab_add(devhandle, bus, + device, func); + if (err) + return err; + } + } + } + + return 0; +} + +static struct pdev_entry *pdev_find(u32 devhandle, unsigned int bus, unsigned int device, unsigned int func) +{ + struct pdev_entry *p; + + p = pdev_htab[pdev_hashfn(devhandle, bus, device, func)]; + while (p) { + if (p->devhandle == devhandle && + p->bus == bus && + p->device == device && + p->func == func) + break; + + p = p->next; } + return p; +} + +static inline int pci_sun4v_out_of_range(struct pci_pbm_info *pbm, unsigned int bus, unsigned int device, unsigned int func) +{ if (bus < pbm->pci_first_busno || bus > pbm->pci_last_busno) return 1; - return 0; + return pdev_find(pbm->devhandle, bus, device, func) == NULL; } static int pci_sun4v_read_pci_cfg(struct pci_bus *bus_dev, unsigned int devfn, @@ -1063,6 +1173,8 @@ static void pci_sun4v_pbm_init(struct pci_controller_info *p, int prom_node, u32 pci_sun4v_get_bus_range(pbm); pci_sun4v_iommu_init(pbm); + + pdev_htab_populate(pbm); } void sun4v_pci_init(int node, char *model_name) -- 2.20.1