--- /dev/null
+From ac9184fbb8478dab4a0724b279f94956b69be827 Mon Sep 17 00:00:00 2001
+From: Takashi Sakamoto <o-takashi@sakamocchi.jp>
+Date: Tue, 2 Jan 2024 20:01:50 +0900
+Subject: firewire: ohci: suppress unexpected system reboot in AMD Ryzen machines and ASM108x/VT630x PCIe cards
+
+From: Takashi Sakamoto <o-takashi@sakamocchi.jp>
+
+commit ac9184fbb8478dab4a0724b279f94956b69be827 upstream.
+
+VIA VT6306/6307/6308 provides PCI interface compliant to 1394 OHCI. When
+the hardware is combined with Asmedia ASM1083/1085 PCIe-to-PCI bus bridge,
+it appears that accesses to its 'Isochronous Cycle Timer' register (offset
+0xf0 on PCI memory space) often causes unexpected system reboot in any
+type of AMD Ryzen machine (both 0x17 and 0x19 families). It does not
+appears in the other type of machine (AMD pre-Ryzen machine, Intel
+machine, at least), or in the other OHCI 1394 hardware (e.g. Texas
+Instruments).
+
+The issue explicitly appears at a commit dcadfd7f7c74 ("firewire: core:
+use union for callback of transaction completion") added to v6.5 kernel.
+It changed 1394 OHCI driver to access to the register every time to
+dispatch local asynchronous transaction. However, the issue exists in
+older version of kernel as long as it runs in AMD Ryzen machine, since
+the access to the register is required to maintain bus time. It is not
+hard to imagine that users experience the unexpected system reboot when
+generating bus reset by plugging any devices in, or reading the register
+by time-aware application programs; e.g. audio sample processing.
+
+This commit suppresses the unexpected system reboot in the combination of
+hardware. It avoids the access itself. As a result, the software stack can
+not provide the hardware time anymore to unit drivers, userspace
+applications, and nodes in the same IEEE 1394 bus. It brings apparent
+disadvantage since time-aware application programs require it, while
+time-unaware applications are available again; e.g. sbp2.
+
+Cc: stable@vger.kernel.org
+Reported-by: Jiri Slaby <jirislaby@kernel.org>
+Closes: https://bugzilla.suse.com/show_bug.cgi?id=1215436
+Reported-by: Mario Limonciello <mario.limonciello@amd.com>
+Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217994
+Reported-by: Tobias Gruetzmacher <tobias-lists@23.gs>
+Closes: https://sourceforge.net/p/linux1394/mailman/message/58711901/
+Closes: https://bugzilla.redhat.com/show_bug.cgi?id=2240973
+Closes: https://bugs.launchpad.net/linux/+bug/2043905
+Link: https://lore.kernel.org/r/20240102110150.244475-1-o-takashi@sakamocchi.jp
+Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/firewire/ohci.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++
+ 1 file changed, 51 insertions(+)
+
+--- a/drivers/firewire/ohci.c
++++ b/drivers/firewire/ohci.c
+@@ -292,6 +292,51 @@ static char ohci_driver_name[] = KBUILD_
+ #define QUIRK_TI_SLLZ059 0x20
+ #define QUIRK_IR_WAKE 0x40
+
++// On PCI Express Root Complex in any type of AMD Ryzen machine, VIA VT6306/6307/6308 with Asmedia
++// ASM1083/1085 brings an inconvenience that the read accesses to 'Isochronous Cycle Timer' register
++// (at offset 0xf0 in PCI I/O space) often causes unexpected system reboot. The mechanism is not
++// clear, since the read access to the other registers is enough safe; e.g. 'Node ID' register,
++// while it is probable due to detection of any type of PCIe error.
++#define QUIRK_REBOOT_BY_CYCLE_TIMER_READ 0x80000000
++
++#if IS_ENABLED(CONFIG_X86)
++
++static bool has_reboot_by_cycle_timer_read_quirk(const struct fw_ohci *ohci)
++{
++ return !!(ohci->quirks & QUIRK_REBOOT_BY_CYCLE_TIMER_READ);
++}
++
++#define PCI_DEVICE_ID_ASMEDIA_ASM108X 0x1080
++
++static bool detect_vt630x_with_asm1083_on_amd_ryzen_machine(const struct pci_dev *pdev)
++{
++ const struct pci_dev *pcie_to_pci_bridge;
++
++ // Detect any type of AMD Ryzen machine.
++ if (!static_cpu_has(X86_FEATURE_ZEN))
++ return false;
++
++ // Detect VIA VT6306/6307/6308.
++ if (pdev->vendor != PCI_VENDOR_ID_VIA)
++ return false;
++ if (pdev->device != PCI_DEVICE_ID_VIA_VT630X)
++ return false;
++
++ // Detect Asmedia ASM1083/1085.
++ pcie_to_pci_bridge = pdev->bus->self;
++ if (pcie_to_pci_bridge->vendor != PCI_VENDOR_ID_ASMEDIA)
++ return false;
++ if (pcie_to_pci_bridge->device != PCI_DEVICE_ID_ASMEDIA_ASM108X)
++ return false;
++
++ return true;
++}
++
++#else
++#define has_reboot_by_cycle_timer_read_quirk(ohci) false
++#define detect_vt630x_with_asm1083_on_amd_ryzen_machine(pdev) false
++#endif
++
+ /* In case of multiple matches in ohci_quirks[], only the first one is used. */
+ static const struct {
+ unsigned short vendor, device, revision, flags;
+@@ -1732,6 +1777,9 @@ static u32 get_cycle_time(struct fw_ohci
+ s32 diff01, diff12;
+ int i;
+
++ if (has_reboot_by_cycle_timer_read_quirk(ohci))
++ return 0;
++
+ c2 = reg_read(ohci, OHCI1394_IsochronousCycleTimer);
+
+ if (ohci->quirks & QUIRK_CYCLE_TIMER) {
+@@ -3635,6 +3683,9 @@ static int pci_probe(struct pci_dev *dev
+ if (param_quirks)
+ ohci->quirks = param_quirks;
+
++ if (detect_vt630x_with_asm1083_on_amd_ryzen_machine(dev))
++ ohci->quirks |= QUIRK_REBOOT_BY_CYCLE_TIMER_READ;
++
+ /*
+ * Because dma_alloc_coherent() allocates at least one page,
+ * we save space by using a common buffer for the AR request/
projects / thirdparty / kernel / stable-queue.git / commitdiff
