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authorKonstantin Belousov <kib@FreeBSD.org>2019-04-09 18:07:17 +0000
committerKonstantin Belousov <kib@FreeBSD.org>2019-04-09 18:07:17 +0000
commit2a508645b463af254d2f1811fb16d7d8eb1d9133 (patch)
tree0e382b9823a5e933d13842200143c21d07127866 /sys/amd64/pci
parentc9c9de9366edd6a05c9dc179ecea17deded478f7 (diff)
downloadsrc-2a508645b463af254d2f1811fb16d7d8eb1d9133.tar.gz
src-2a508645b463af254d2f1811fb16d7d8eb1d9133.zip
pci_cfgreg.c: Use io port config access for early boot time.
Some early PCIe chipsets are explicitly listed in the white-list to enable use of the MMIO config space accesses, perhaps because ACPI tables were not reliable source of the base MCFG address at that time. For that chipsets, MCFG base was read from the known chipset MCFGbase config register. During very early stage of boot, when access to the PCI config space is performed (see e.g. pci_early_quirks.c), we cannot map 255MB of registers because the method used with pre-boot pmap overflows initial kernel page tables. Move fallback to read MCFGbase to the attachment method of the x86/legacy device, which removes code duplication, and results in the use of io accesses until MCFG is parsed or legacy attach called. For amd64, pre-initialize cfgmech with CFGMECH_1, right now we dynamically assign CFGMECH_1 to it anyway, and remove checks for CFGMECH_NONE. There is a mention in the Intel documentation for corresponding chipsets that OS must use either io port or MMIO access method, but we already break this rule by reading MCFGbase register, so one more access seems to be innocent. Reported by: longwitz@incore.de PR: 236838 Reviewed by: avg (other version), jhb Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D19833
Notes
Notes: svn path=/head/; revision=346062
Diffstat (limited to 'sys/amd64/pci')
-rw-r--r--sys/amd64/pci/pci_cfgreg.c57
1 files changed, 7 insertions, 50 deletions
diff --git a/sys/amd64/pci/pci_cfgreg.c b/sys/amd64/pci/pci_cfgreg.c
index 90eba9198410..7e6eee79ba7a 100644
--- a/sys/amd64/pci/pci_cfgreg.c
+++ b/sys/amd64/pci/pci_cfgreg.c
@@ -44,12 +44,6 @@ __FBSDID("$FreeBSD$");
#include <vm/pmap.h>
#include <machine/pci_cfgreg.h>
-enum {
- CFGMECH_NONE = 0,
- CFGMECH_1,
- CFGMECH_PCIE,
-};
-
static uint32_t pci_docfgregread(int bus, int slot, int func, int reg,
int bytes);
static int pciereg_cfgread(int bus, unsigned slot, unsigned func,
@@ -61,7 +55,13 @@ static void pcireg_cfgwrite(int bus, int slot, int func, int reg, int data, int
SYSCTL_DECL(_hw_pci);
-static int cfgmech;
+/*
+ * For amd64 we assume that type 1 I/O port-based access always works.
+ * If an ACPI MCFG table exists, pcie_cfgregopen() will be called to
+ * switch to memory-mapped access.
+ */
+int cfgmech = CFGMECH_1;
+
static vm_offset_t pcie_base;
static int pcie_minbus, pcie_maxbus;
static uint32_t pcie_badslots;
@@ -71,46 +71,9 @@ static int mcfg_enable = 1;
SYSCTL_INT(_hw_pci, OID_AUTO, mcfg, CTLFLAG_RDTUN, &mcfg_enable, 0,
"Enable support for PCI-e memory mapped config access");
-/*
- * Initialise access to PCI configuration space
- */
int
pci_cfgregopen(void)
{
- uint64_t pciebar;
- uint16_t did, vid;
-
- if (cfgmech != CFGMECH_NONE)
- return (1);
- cfgmech = CFGMECH_1;
-
- /*
- * Grope around in the PCI config space to see if this is a
- * chipset that is capable of doing memory-mapped config cycles.
- * This also implies that it can do PCIe extended config cycles.
- */
-
- /* Check for supported chipsets */
- vid = pci_cfgregread(0, 0, 0, PCIR_VENDOR, 2);
- did = pci_cfgregread(0, 0, 0, PCIR_DEVICE, 2);
- switch (vid) {
- case 0x8086:
- switch (did) {
- case 0x3590:
- case 0x3592:
- /* Intel 7520 or 7320 */
- pciebar = pci_cfgregread(0, 0, 0, 0xce, 2) << 16;
- pcie_cfgregopen(pciebar, 0, 255);
- break;
- case 0x2580:
- case 0x2584:
- case 0x2590:
- /* Intel 915, 925, or 915GM */
- pciebar = pci_cfgregread(0, 0, 0, 0x48, 4);
- pcie_cfgregopen(pciebar, 0, 255);
- break;
- }
- }
return (1);
}
@@ -135,9 +98,6 @@ pci_cfgregread(int bus, int slot, int func, int reg, int bytes)
{
uint32_t line;
- if (cfgmech == CFGMECH_NONE)
- return (0xffffffff);
-
/*
* Some BIOS writers seem to want to ignore the spec and put
* 0 in the intline rather than 255 to indicate none. Some use
@@ -162,9 +122,6 @@ void
pci_cfgregwrite(int bus, int slot, int func, int reg, u_int32_t data, int bytes)
{
- if (cfgmech == CFGMECH_NONE)
- return;
-
if (cfgmech == CFGMECH_PCIE &&
(bus >= pcie_minbus && bus <= pcie_maxbus) &&
(bus != 0 || !(1 << slot & pcie_badslots)))