From 7bf9d2af7e89f65a79225e26d261b52ce4ee3e95 Mon Sep 17 00:00:00 2001 From: Vidya Sagar Date: Tue, 16 Jan 2024 20:02:58 +0530 Subject: PCI: Clear Secondary Status errors after enumeration We enumerate devices by attempting config reads to the Vendor ID of each possible device. On conventional PCI, if no device responds, the read terminates with a Master Abort (PCI r3.0, sec 6.1). On PCIe, the config read is terminated as an Unsupported Request (PCIe r6.0, sec 2.3.2, 7.5.1.3.7). In either case, if the read addressed a device below a bridge, it is logged by setting "Received Master Abort" in the bridge Secondary Status register. Clear any errors logged in the Secondary Status register after enumeration. Link: https://lore.kernel.org/r/20240116143258.483235-1-vidyas@nvidia.com Signed-off-by: Vidya Sagar [bhelgaas: simplify commit log] Signed-off-by: Bjorn Helgaas --- drivers/pci/probe.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers/pci') diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 1325fbae2f28..df5171b912e0 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1482,6 +1482,9 @@ static int pci_scan_bridge_extend(struct pci_bus *bus, struct pci_dev *dev, } out: + /* Clear errors in the Secondary Status Register */ + pci_write_config_word(dev, PCI_SEC_STATUS, 0xffff); + pci_write_config_word(dev, PCI_BRIDGE_CONTROL, bctl); pm_runtime_put(&dev->dev); -- cgit v1.2.3 From 73cb3a35f94db723c0211ad099bce55b2155e3f0 Mon Sep 17 00:00:00 2001 From: Ilpo Järvinen Date: Tue, 23 Apr 2024 16:08:19 +0300 Subject: PCI: Wait for Link Training==0 before starting Link retrain MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Two changes were made in link retraining logic independent of each other. The commit e7e39756363a ("PCI/ASPM: Avoid link retraining race") added a check to pcie_retrain_link() to ensure no Link Training is currently active to address the Implementation Note in PCIe r6.1 sec 7.5.3.7. At that time pcie_wait_for_retrain() only checked for the Link Training (LT) bit being cleared. The commit 680e9c47a229 ("PCI: Add support for polling DLLLA to pcie_retrain_link()") generalized pcie_wait_for_retrain() into pcie_wait_for_link_status() which can wait either for LT or the Data Link Layer Link Active (DLLLA) bit with 'use_lt' argument and supporting waiting for either cleared or set using 'active' argument. In the merge commit 1abb47390350 ("Merge branch 'pci/enumeration'"), those two divergent branches converged. The merge changed LT bit checking added in the commit e7e39756363a ("PCI/ASPM: Avoid link retraining race") to now wait for completion of any ongoing Link Training using DLLLA bit being set if 'use_lt' is false. When 'use_lt' is false, the pseudo-code steps of what occurs in pcie_retrain_link(): 1. Wait for DLLLA==1 2. Trigger link to retrain 3. Wait for DLLLA==1 Step 3 waits for the link to come up from the retraining triggered by Step 2. As Step 1 is supposed to wait for any ongoing retraining to end, using DLLLA also for it does not make sense because link training being active is still indicated using LT bit, not with DLLLA. Correct the pcie_wait_for_link_status() parameters in Step 1 to only wait for LT==0 to ensure there is no ongoing Link Training. This only impacts the Target Speed quirk, which is the only case where waiting for DLLLA bit is used. It currently works in the problematic case by means of link training getting initiated by hardware repeatedly and respecting the new link parameters set by the caller, which then make training succeed and bring the link up, setting DLLLA and causing pcie_wait_for_link_status() to return success. We are not supposed to rely on luck and need to make sure that LT transitioned through the inactive state though before we initiate link training by hand via RL (Retrain Link) bit. Fixes: 1abb47390350 ("Merge branch 'pci/enumeration'") Link: https://lore.kernel.org/r/20240423130820.43824-1-ilpo.jarvinen@linux.intel.com Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas --- drivers/pci/pci.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/pci') diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index e5f243dd4288..70b8c87055cb 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4629,7 +4629,7 @@ int pcie_retrain_link(struct pci_dev *pdev, bool use_lt) * avoid LTSSM race as recommended in Implementation Note at the * end of PCIe r6.0.1 sec 7.5.3.7. */ - rc = pcie_wait_for_link_status(pdev, use_lt, !use_lt); + rc = pcie_wait_for_link_status(pdev, true, false); if (rc) return rc; -- cgit v1.2.3 From cdc6c4abcb313be1b7118b6e86eb99a85a626578 Mon Sep 17 00:00:00 2001 From: Ilpo Järvinen Date: Tue, 23 Apr 2024 16:08:20 +0300 Subject: PCI: Clarify intent of LT wait MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Clarify the comment relating to the LT wait and the purpose of the check that implements the implementation note in PCIe r6.1 sec 7.5.3.7. Suggested-by: Maciej W. Rozycki Link: https://lore.kernel.org/r/20240423130820.43824-2-ilpo.jarvinen@linux.intel.com Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas --- drivers/pci/pci.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'drivers/pci') diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 70b8c87055cb..5a25facb3ce7 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4625,9 +4625,10 @@ int pcie_retrain_link(struct pci_dev *pdev, bool use_lt) /* * Ensure the updated LNKCTL parameters are used during link - * training by checking that there is no ongoing link training to - * avoid LTSSM race as recommended in Implementation Note at the - * end of PCIe r6.0.1 sec 7.5.3.7. + * training by checking that there is no ongoing link training that + * may have started before link parameters were changed, so as to + * avoid LTSSM race as recommended in Implementation Note at the end + * of PCIe r6.1 sec 7.5.3.7. */ rc = pcie_wait_for_link_status(pdev, true, false); if (rc) -- cgit v1.2.3 From bb14a6a870548d44e486c7d68d47c2114aafb395 Mon Sep 17 00:00:00 2001 From: Damien Le Moal Date: Mon, 25 Mar 2024 16:09:12 +0900 Subject: PCI/MSI: Use PCI_IRQ_INTX instead of PCI_IRQ_LEGACY In pci_alloc_irq_vectors_affinity(), use the macro PCI_IRQ_INTX instead of the now deprecated PCI_IRQ_LEGACY macro. Link: https://lore.kernel.org/r/20240325070944.3600338-2-dlemoal@kernel.org Signed-off-by: Damien Le Moal Signed-off-by: Bjorn Helgaas --- drivers/pci/msi/api.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'drivers/pci') diff --git a/drivers/pci/msi/api.c b/drivers/pci/msi/api.c index be679aa5db64..dfba4d6dd535 100644 --- a/drivers/pci/msi/api.c +++ b/drivers/pci/msi/api.c @@ -213,8 +213,8 @@ EXPORT_SYMBOL(pci_disable_msix); * * %PCI_IRQ_MSIX Allow trying MSI-X vector allocations * * %PCI_IRQ_MSI Allow trying MSI vector allocations * - * * %PCI_IRQ_LEGACY Allow trying legacy INTx interrupts, if - * and only if @min_vecs == 1 + * * %PCI_IRQ_INTX Allow trying INTx interrupts, if and + * only if @min_vecs == 1 * * * %PCI_IRQ_AFFINITY Auto-manage IRQs affinity by spreading * the vectors around available CPUs @@ -279,8 +279,8 @@ int pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs, return nvecs; } - /* use legacy IRQ if allowed */ - if (flags & PCI_IRQ_LEGACY) { + /* use INTx IRQ if allowed */ + if (flags & PCI_IRQ_INTX) { if (min_vecs == 1 && dev->irq) { /* * Invoke the affinity spreading logic to ensure that -- cgit v1.2.3 From a665b0a93f3bf64b899893938c6fc4ed246ef59f Mon Sep 17 00:00:00 2001 From: Damien Le Moal Date: Mon, 25 Mar 2024 16:09:13 +0900 Subject: PCI/portdrv: Use PCI_IRQ_INTX instead of PCI_IRQ_LEGACY In the PCI Express Port Bus Driver, use the macro PCI_IRQ_INTX instead of the now deprecated PCI_IRQ_LEGACY macro. Link: https://lore.kernel.org/r/20240325070944.3600338-3-dlemoal@kernel.org Signed-off-by: Damien Le Moal Signed-off-by: Bjorn Helgaas --- drivers/pci/pcie/portdrv.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'drivers/pci') diff --git a/drivers/pci/pcie/portdrv.c b/drivers/pci/pcie/portdrv.c index 14a4b89a3b83..bb65dfe43409 100644 --- a/drivers/pci/pcie/portdrv.c +++ b/drivers/pci/pcie/portdrv.c @@ -187,15 +187,15 @@ static int pcie_init_service_irqs(struct pci_dev *dev, int *irqs, int mask) * interrupt. */ if ((mask & PCIE_PORT_SERVICE_PME) && pcie_pme_no_msi()) - goto legacy_irq; + goto intx_irq; /* Try to use MSI-X or MSI if supported */ if (pcie_port_enable_irq_vec(dev, irqs, mask) == 0) return 0; -legacy_irq: - /* fall back to legacy IRQ */ - ret = pci_alloc_irq_vectors(dev, 1, 1, PCI_IRQ_LEGACY); +intx_irq: + /* fall back to INTX IRQ */ + ret = pci_alloc_irq_vectors(dev, 1, 1, PCI_IRQ_INTX); if (ret < 0) return -ENODEV; -- cgit v1.2.3 From 844177a80753fc173131f3e591124c8dcbc89812 Mon Sep 17 00:00:00 2001 From: Heiner Kallweit Date: Sat, 23 Mar 2024 18:16:36 +0100 Subject: PCI: Remove unused pci_enable_device_io() After the last user was removed, remove this PCI core function. It's very unlikely that we'll see a new device requiring io space access, even though memory space access is supported. Link: https://lore.kernel.org/r/213ebf62-53a3-42b7-8518-ecd5cd6d6b08@gmail.com Signed-off-by: Heiner Kallweit Signed-off-by: Bjorn Helgaas Reviewed-by: Damien Le Moal --- drivers/pci/pci.c | 14 -------------- include/linux/pci.h | 1 - 2 files changed, 15 deletions(-) (limited to 'drivers/pci') diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 5a25facb3ce7..d3fabfca7e6f 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -2110,20 +2110,6 @@ static int pci_enable_device_flags(struct pci_dev *dev, unsigned long flags) return err; } -/** - * pci_enable_device_io - Initialize a device for use with IO space - * @dev: PCI device to be initialized - * - * Initialize device before it's used by a driver. Ask low-level code - * to enable I/O resources. Wake up the device if it was suspended. - * Beware, this function can fail. - */ -int pci_enable_device_io(struct pci_dev *dev) -{ - return pci_enable_device_flags(dev, IORESOURCE_IO); -} -EXPORT_SYMBOL(pci_enable_device_io); - /** * pci_enable_device_mem - Initialize a device for use with Memory space * @dev: PCI device to be initialized diff --git a/include/linux/pci.h b/include/linux/pci.h index 6a09bd9636d5..69b10f2fb606 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1313,7 +1313,6 @@ int pci_user_write_config_word(struct pci_dev *dev, int where, u16 val); int pci_user_write_config_dword(struct pci_dev *dev, int where, u32 val); int __must_check pci_enable_device(struct pci_dev *dev); -int __must_check pci_enable_device_io(struct pci_dev *dev); int __must_check pci_enable_device_mem(struct pci_dev *dev); int __must_check pci_reenable_device(struct pci_dev *); int __must_check pcim_enable_device(struct pci_dev *pdev); -- cgit v1.2.3 From 6613443ffc49d03e27f0404978f685c4eac43fba Mon Sep 17 00:00:00 2001 From: Ilpo Järvinen Date: Thu, 8 Feb 2024 15:23:21 +0200 Subject: PCI: Do not wait for disconnected devices when resuming MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On runtime resume, pci_dev_wait() is called: pci_pm_runtime_resume() pci_pm_bridge_power_up_actions() pci_bridge_wait_for_secondary_bus() pci_dev_wait() While a device is runtime suspended along with its PCI hierarchy, the device could get disconnected. In such case, the link will not come up no matter how long pci_dev_wait() waits for it. Besides the above mentioned case, there could be other ways to get the device disconnected while pci_dev_wait() is waiting for the link to come up. Make pci_dev_wait() exit if the device is already disconnected to avoid unnecessary delay. The use cases of pci_dev_wait() boil down to two: 1. Waiting for the device after reset 2. pci_bridge_wait_for_secondary_bus() The callers in both cases seem to benefit from propagating the disconnection as error even if device disconnection would be more analoguous to the case where there is no device in the first place which return 0 from pci_dev_wait(). In the case 2, it results in unnecessary marking of the devices disconnected again but that is just harmless extra work. Also make sure compiler does not become too clever with dev->error_state and use READ_ONCE() to force a fetch for the up-to-date value. Link: https://lore.kernel.org/r/20240208132322.4811-1-ilpo.jarvinen@linux.intel.com Reported-by: Mika Westerberg Tested-by: Mika Westerberg Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas --- drivers/pci/pci.c | 5 +++++ include/linux/pci.h | 7 ++++++- 2 files changed, 11 insertions(+), 1 deletion(-) (limited to 'drivers/pci') diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index d3fabfca7e6f..a9848316c623 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -1277,6 +1277,11 @@ static int pci_dev_wait(struct pci_dev *dev, char *reset_type, int timeout) for (;;) { u32 id; + if (pci_dev_is_disconnected(dev)) { + pci_dbg(dev, "disconnected; not waiting\n"); + return -ENOTTY; + } + pci_read_config_dword(dev, PCI_COMMAND, &id); if (!PCI_POSSIBLE_ERROR(id)) break; diff --git a/include/linux/pci.h b/include/linux/pci.h index 69b10f2fb606..2151c7f9be86 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -2514,7 +2514,12 @@ static inline struct pci_dev *pcie_find_root_port(struct pci_dev *dev) static inline bool pci_dev_is_disconnected(const struct pci_dev *dev) { - return dev->error_state == pci_channel_io_perm_failure; + /* + * error_state is set in pci_dev_set_io_state() using xchg/cmpxchg() + * and read w/o common lock. READ_ONCE() ensures compiler cannot cache + * the value (e.g. inside the loop in pci_dev_wait()). + */ + return READ_ONCE(dev->error_state) == pci_channel_io_perm_failure; } void pci_request_acs(void); -- cgit v1.2.3