Commit-ID: 556e4c62baffa71e2045a298379db7e57dd47f3d Gitweb: https://git.kernel.org/tip/556e4c62baffa71e2045a298379db7e57dd47f3d Author: Woods, Brian <Brian.Woods@xxxxxxx> AuthorDate: Tue, 6 Nov 2018 20:08:16 +0000 Committer: Borislav Petkov <bp@xxxxxxx> CommitDate: Wed, 7 Nov 2018 21:28:29 +0100 x86/amd_nb: Add support for newer PCI topologies Add support for new processors which have multiple PCI root complexes per data fabric/system management network interface. If there are (N) multiple PCI roots per DF/SMN interface, then the PCI roots are redundant (as far as SMN/DF access goes). For each DF/SMN interface: map to the first available PCI root and skip the next N-1 PCI roots so the following DF/SMN interface get mapped to a correct PCI root. Ex: DF/SMN 0 -> 60 40 20 00 DF/SMN 1 -> e0 c0 a0 80 Signed-off-by: Brian Woods <brian.woods@xxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> CC: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> CC: Clemens Ladisch <clemens@xxxxxxxxxx> CC: Guenter Roeck <linux@xxxxxxxxxxxx> CC: "H. Peter Anvin" <hpa@xxxxxxxxx> CC: Ingo Molnar <mingo@xxxxxxxxxx> CC: Jean Delvare <jdelvare@xxxxxxxx> CC: Jia Zhang <qianyue.zj@xxxxxxxxxxxxxxx> CC: <linux-hwmon@xxxxxxxxxxxxxxx> CC: <linux-pci@xxxxxxxxxxxxxxx> CC: Pu Wen <puwen@xxxxxxxx> CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CC: x86-ml <x86@xxxxxxxxxx> Link: http://lkml.kernel.org/r/20181106200754.60722-3-brian.woods@xxxxxxx --- arch/x86/kernel/amd_nb.c | 44 ++++++++++++++++++++++++++++++++++++++------ 1 file changed, 38 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/amd_nb.c b/arch/x86/kernel/amd_nb.c index 19d489ee2b1e..cc34266e3c62 100644 --- a/arch/x86/kernel/amd_nb.c +++ b/arch/x86/kernel/amd_nb.c @@ -213,7 +213,10 @@ int amd_cache_northbridges(void) const struct pci_device_id *root_ids = amd_root_ids; struct pci_dev *root, *misc, *link; struct amd_northbridge *nb; - u16 i = 0; + u16 roots_per_misc = 0; + u16 misc_count = 0; + u16 root_count = 0; + u16 i, j; if (amd_northbridges.num) return 0; @@ -226,26 +229,55 @@ int amd_cache_northbridges(void) misc = NULL; while ((misc = next_northbridge(misc, misc_ids)) != NULL) - i++; + misc_count++; - if (!i) + if (!misc_count) return -ENODEV; - nb = kcalloc(i, sizeof(struct amd_northbridge), GFP_KERNEL); + root = NULL; + while ((root = next_northbridge(root, root_ids)) != NULL) + root_count++; + + if (root_count) { + roots_per_misc = root_count / misc_count; + + /* + * There should be _exactly_ N roots for each DF/SMN + * interface. + */ + if (!roots_per_misc || (root_count % roots_per_misc)) { + pr_info("Unsupported AMD DF/PCI configuration found\n"); + return -ENODEV; + } + } + + nb = kcalloc(misc_count, sizeof(struct amd_northbridge), GFP_KERNEL); if (!nb) return -ENOMEM; amd_northbridges.nb = nb; - amd_northbridges.num = i; + amd_northbridges.num = misc_count; link = misc = root = NULL; - for (i = 0; i != amd_northbridges.num; i++) { + for (i = 0; i < amd_northbridges.num; i++) { node_to_amd_nb(i)->root = root = next_northbridge(root, root_ids); node_to_amd_nb(i)->misc = misc = next_northbridge(misc, misc_ids); node_to_amd_nb(i)->link = link = next_northbridge(link, link_ids); + + /* + * If there are more PCI root devices than data fabric/ + * system management network interfaces, then the (N) + * PCI roots per DF/SMN interface are functionally the + * same (for DF/SMN access) and N-1 are redundant. N-1 + * PCI roots should be skipped per DF/SMN interface so + * the following DF/SMN interfaces get mapped to + * correct PCI roots. + */ + for (j = 1; j < roots_per_misc; j++) + root = next_northbridge(root, root_ids); } if (amd_gart_present())
