From da87d35a6e51480703d6f055e7a1b52c85731d7e Mon Sep 17 00:00:00 2001 From: Manivannan Sadhasivam Date: Tue, 24 Jan 2023 12:41:54 +0530 Subject: PCI: dra7xx: Use threaded IRQ handler for "dra7xx-pcie-main" IRQ MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The "dra7xx-pcie-main" hard IRQ handler is just printing the IRQ status and calling the dw_pcie_ep_linkup() API if LINK_UP status is set. But the execution of dw_pcie_ep_linkup() depends on the EPF driver and may take more time depending on the EPF implementation. In general, hard IRQ handlers are supposed to return quickly and not block for so long. Moreover, there is no real need of the current IRQ handler to be a hard IRQ handler. So switch to the threaded IRQ handler for the "dra7xx-pcie-main" IRQ. Link: https://lore.kernel.org/linux-pci/20230124071158.5503-2-manivannan.sadhasivam@linaro.org Signed-off-by: Manivannan Sadhasivam Signed-off-by: Krzysztof Wilczyński Acked-by: Kishon Vijay Abraham I --- drivers/pci/controller/dwc/pci-dra7xx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/pci') diff --git a/drivers/pci/controller/dwc/pci-dra7xx.c b/drivers/pci/controller/dwc/pci-dra7xx.c index 38462ed11d07..4ae807e7cf79 100644 --- a/drivers/pci/controller/dwc/pci-dra7xx.c +++ b/drivers/pci/controller/dwc/pci-dra7xx.c @@ -840,7 +840,7 @@ static int dra7xx_pcie_probe(struct platform_device *pdev) } dra7xx->mode = mode; - ret = devm_request_irq(dev, irq, dra7xx_pcie_irq_handler, + ret = devm_request_threaded_irq(dev, irq, NULL, dra7xx_pcie_irq_handler, IRQF_SHARED, "dra7xx-pcie-main", dra7xx); if (ret) { dev_err(dev, "failed to request irq\n"); -- cgit v1.2.3 From c2cc5cdda46c0a94ff82bf61016ada2e120f1a3f Mon Sep 17 00:00:00 2001 From: Manivannan Sadhasivam Date: Tue, 24 Jan 2023 12:41:55 +0530 Subject: PCI: tegra194: Move dw_pcie_ep_linkup() to threaded IRQ handler MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit dw_pcie_ep_linkup() may take more time to execute depending on the EPF driver implementation. Calling this API in the hard IRQ handler is not encouraged since the hard IRQ handlers are supposed to complete quickly. So move the dw_pcie_ep_linkup() call to threaded IRQ handler. Link: https://lore.kernel.org/linux-pci/20230124071158.5503-3-manivannan.sadhasivam@linaro.org Signed-off-by: Manivannan Sadhasivam Signed-off-by: Krzysztof Wilczyński Reviewed-by: Vidya Sagar --- drivers/pci/controller/dwc/pcie-tegra194.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'drivers/pci') diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c index 02d78a12b6e7..09825b4a075e 100644 --- a/drivers/pci/controller/dwc/pcie-tegra194.c +++ b/drivers/pci/controller/dwc/pcie-tegra194.c @@ -286,6 +286,7 @@ struct tegra_pcie_dw { struct gpio_desc *pex_refclk_sel_gpiod; unsigned int pex_rst_irq; int ep_state; + long link_status; }; static inline struct tegra_pcie_dw *to_tegra_pcie(struct dw_pcie *pci) @@ -449,9 +450,13 @@ static void pex_ep_event_hot_rst_done(struct tegra_pcie_dw *pcie) static irqreturn_t tegra_pcie_ep_irq_thread(int irq, void *arg) { struct tegra_pcie_dw *pcie = arg; + struct dw_pcie_ep *ep = &pcie->pci.ep; struct dw_pcie *pci = &pcie->pci; u32 val, speed; + if (test_and_clear_bit(0, &pcie->link_status)) + dw_pcie_ep_linkup(ep); + speed = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA) & PCI_EXP_LNKSTA_CLS; clk_set_rate(pcie->core_clk, pcie_gen_freq[speed - 1]); @@ -498,7 +503,6 @@ static irqreturn_t tegra_pcie_ep_irq_thread(int irq, void *arg) static irqreturn_t tegra_pcie_ep_hard_irq(int irq, void *arg) { struct tegra_pcie_dw *pcie = arg; - struct dw_pcie_ep *ep = &pcie->pci.ep; int spurious = 1; u32 status_l0, status_l1, link_status; @@ -514,7 +518,8 @@ static irqreturn_t tegra_pcie_ep_hard_irq(int irq, void *arg) link_status = appl_readl(pcie, APPL_LINK_STATUS); if (link_status & APPL_LINK_STATUS_RDLH_LINK_UP) { dev_dbg(pcie->dev, "Link is up with Host\n"); - dw_pcie_ep_linkup(ep); + set_bit(0, &pcie->link_status); + return IRQ_WAKE_THREAD; } } -- cgit v1.2.3 From d6dd5bafaabf98a99a76227ab8dc9a89e76a198f Mon Sep 17 00:00:00 2001 From: Manivannan Sadhasivam Date: Tue, 24 Jan 2023 12:41:56 +0530 Subject: PCI: endpoint: Use a separate lock for protecting epc->pci_epf list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The EPC controller maintains a list of EPF drivers added to it. For protecting this list against the concurrent accesses, the epc->lock (used for protecting epc_ops) has been used so far. Since there were no users trying to use epc_ops and modify the pci_epf list simultaneously, this was not an issue. But with the addition of callback mechanism for passing the events, this will be a problem. Because the pci_epf list needs to be iterated first for getting hold of the EPF driver and then the relevant event specific callback needs to be called for the driver. If the same epc->lock is used, then it will result in a deadlock scenario. For instance, ... mutex_lock(&epc->lock); list_for_each_entry(epf, &epc->pci_epf, list) { epf->event_ops->core_init(epf); | |-> pci_epc_set_bar(); | |-> mutex_lock(&epc->lock) # DEADLOCK ... So to fix this issue, use a separate lock called "list_lock" for protecting the pci_epf list against the concurrent accesses. This lock will also be used by the callback mechanism. Link: https://lore.kernel.org/linux-pci/20230124071158.5503-4-manivannan.sadhasivam@linaro.org Signed-off-by: Manivannan Sadhasivam Signed-off-by: Krzysztof Wilczyński Acked-by: Kishon Vijay Abraham I --- drivers/pci/endpoint/pci-epc-core.c | 9 +++++---- include/linux/pci-epc.h | 2 ++ 2 files changed, 7 insertions(+), 4 deletions(-) (limited to 'drivers/pci') diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c index 2542196e8c3d..2c023db8f51c 100644 --- a/drivers/pci/endpoint/pci-epc-core.c +++ b/drivers/pci/endpoint/pci-epc-core.c @@ -613,7 +613,7 @@ int pci_epc_add_epf(struct pci_epc *epc, struct pci_epf *epf, if (type == SECONDARY_INTERFACE && epf->sec_epc) return -EBUSY; - mutex_lock(&epc->lock); + mutex_lock(&epc->list_lock); func_no = find_first_zero_bit(&epc->function_num_map, BITS_PER_LONG); if (func_no >= BITS_PER_LONG) { @@ -640,7 +640,7 @@ int pci_epc_add_epf(struct pci_epc *epc, struct pci_epf *epf, list_add_tail(list, &epc->pci_epf); ret: - mutex_unlock(&epc->lock); + mutex_unlock(&epc->list_lock); return ret; } @@ -672,11 +672,11 @@ void pci_epc_remove_epf(struct pci_epc *epc, struct pci_epf *epf, list = &epf->sec_epc_list; } - mutex_lock(&epc->lock); + mutex_lock(&epc->list_lock); clear_bit(func_no, &epc->function_num_map); list_del(list); epf->epc = NULL; - mutex_unlock(&epc->lock); + mutex_unlock(&epc->list_lock); } EXPORT_SYMBOL_GPL(pci_epc_remove_epf); @@ -777,6 +777,7 @@ __pci_epc_create(struct device *dev, const struct pci_epc_ops *ops, } mutex_init(&epc->lock); + mutex_init(&epc->list_lock); INIT_LIST_HEAD(&epc->pci_epf); ATOMIC_INIT_NOTIFIER_HEAD(&epc->notifier); diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h index a48778e1a4ee..fe729dfe509b 100644 --- a/include/linux/pci-epc.h +++ b/include/linux/pci-epc.h @@ -122,6 +122,7 @@ struct pci_epc_mem { * struct pci_epc - represents the PCI EPC device * @dev: PCI EPC device * @pci_epf: list of endpoint functions present in this EPC device + * list_lock: Mutex for protecting pci_epf list * @ops: function pointers for performing endpoint operations * @windows: array of address space of the endpoint controller * @mem: first window of the endpoint controller, which corresponds to @@ -139,6 +140,7 @@ struct pci_epc_mem { struct pci_epc { struct device dev; struct list_head pci_epf; + struct mutex list_lock; const struct pci_epc_ops *ops; struct pci_epc_mem **windows; struct pci_epc_mem *mem; -- cgit v1.2.3 From 838125b07e7706b1a9069079a73507fd3df244f7 Mon Sep 17 00:00:00 2001 From: Manivannan Sadhasivam Date: Tue, 24 Jan 2023 12:41:57 +0530 Subject: PCI: endpoint: Use callback mechanism for passing events from EPC to EPF MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Instead of using the notifiers for passing the events from EPC to EPF, let's introduce a callback based mechanism where the EPF drivers can populate relevant callbacks for EPC events they want to subscribe. The use of notifiers in kernel is not recommended if there is a real link between the sender and receiver, like in this case. Also, the existing atomic notifier forces the notification functions to be in atomic context while the caller may be in non-atomic context. For instance, the two in-kernel users of the notifiers, pcie-qcom and pcie-tegra194, both are calling the notifier functions in non-atomic context (from threaded IRQ handlers). This creates a sleeping in atomic context issue with the existing EPF_TEST driver that calls the EPC APIs that may sleep. For all these reasons, let's get rid of the notifier chains and use the simple callback mechanism for signalling the events from EPC to EPF drivers. This preserves the context of the caller and avoids the latency of going through a separate interface for triggering the notifications. As a first step of the transition, the core_init() callback is introduced in this commit, that'll replace the existing CORE_INIT notifier used for signalling the init complete event from EPC. During the occurrence of the event, EPC will go over the list of EPF drivers attached to it and will call the core_init() callback if available. Link: https://lore.kernel.org/linux-pci/20230124071158.5503-5-manivannan.sadhasivam@linaro.org Signed-off-by: Manivannan Sadhasivam Signed-off-by: Krzysztof Wilczyński Acked-by: Kishon Vijay Abraham I --- drivers/pci/endpoint/functions/pci-epf-test.c | 13 ++++++------- drivers/pci/endpoint/pci-epc-core.c | 11 ++++++++++- include/linux/pci-epf.h | 11 ++++++++++- 3 files changed, 26 insertions(+), 9 deletions(-) (limited to 'drivers/pci') diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c index 55283d2379a6..2fe161747e51 100644 --- a/drivers/pci/endpoint/functions/pci-epf-test.c +++ b/drivers/pci/endpoint/functions/pci-epf-test.c @@ -826,20 +826,17 @@ static int pci_epf_test_core_init(struct pci_epf *epf) return 0; } +static const struct pci_epc_event_ops pci_epf_test_event_ops = { + .core_init = pci_epf_test_core_init, +}; + static int pci_epf_test_notifier(struct notifier_block *nb, unsigned long val, void *data) { struct pci_epf *epf = container_of(nb, struct pci_epf, nb); struct pci_epf_test *epf_test = epf_get_drvdata(epf); - int ret; switch (val) { - case CORE_INIT: - ret = pci_epf_test_core_init(epf); - if (ret) - return NOTIFY_BAD; - break; - case LINK_UP: queue_delayed_work(kpcitest_workqueue, &epf_test->cmd_handler, msecs_to_jiffies(1)); @@ -1010,6 +1007,8 @@ static int pci_epf_test_probe(struct pci_epf *epf) INIT_DELAYED_WORK(&epf_test->cmd_handler, pci_epf_test_cmd_handler); + epf->event_ops = &pci_epf_test_event_ops; + epf_set_drvdata(epf, epf_test); return 0; } diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c index 2c023db8f51c..7cb9587c6548 100644 --- a/drivers/pci/endpoint/pci-epc-core.c +++ b/drivers/pci/endpoint/pci-epc-core.c @@ -707,10 +707,19 @@ EXPORT_SYMBOL_GPL(pci_epc_linkup); */ void pci_epc_init_notify(struct pci_epc *epc) { + struct pci_epf *epf; + if (!epc || IS_ERR(epc)) return; - atomic_notifier_call_chain(&epc->notifier, CORE_INIT, NULL); + mutex_lock(&epc->list_lock); + list_for_each_entry(epf, &epc->pci_epf, list) { + mutex_lock(&epf->lock); + if (epf->event_ops && epf->event_ops->core_init) + epf->event_ops->core_init(epf); + mutex_unlock(&epf->lock); + } + mutex_unlock(&epc->list_lock); } EXPORT_SYMBOL_GPL(pci_epc_init_notify); diff --git a/include/linux/pci-epf.h b/include/linux/pci-epf.h index 009a07147c61..fa629c191f00 100644 --- a/include/linux/pci-epf.h +++ b/include/linux/pci-epf.h @@ -18,7 +18,6 @@ struct pci_epf; enum pci_epc_interface_type; enum pci_notify_event { - CORE_INIT, LINK_UP, }; @@ -72,6 +71,14 @@ struct pci_epf_ops { struct config_group *group); }; +/** + * struct pci_epf_event_ops - Callbacks for capturing the EPC events + * @core_init: Callback for the EPC initialization complete event + */ +struct pci_epc_event_ops { + int (*core_init)(struct pci_epf *epf); +}; + /** * struct pci_epf_driver - represents the PCI EPF driver * @probe: ops to perform when a new EPF device has been bound to the EPF driver @@ -139,6 +146,7 @@ struct pci_epf_bar { * @is_vf: true - virtual function, false - physical function * @vfunction_num_map: bitmap to manage virtual function number * @pci_vepf: list of virtual endpoint functions associated with this function + * @event_ops: Callbacks for capturing the EPC events */ struct pci_epf { struct device dev; @@ -168,6 +176,7 @@ struct pci_epf { unsigned int is_vf; unsigned long vfunction_num_map; struct list_head pci_vepf; + const struct pci_epc_event_ops *event_ops; }; /** -- cgit v1.2.3 From f5edd8715e2ea672e6119c3764041743761fb178 Mon Sep 17 00:00:00 2001 From: Manivannan Sadhasivam Date: Tue, 24 Jan 2023 12:41:58 +0530 Subject: PCI: endpoint: Use link_up() callback in place of LINK_UP notifier MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit As a part of the transition towards callback mechanism for signalling the events from EPC to EPF, let's use the link_up() callback in the place of the LINK_UP notifier. This also removes the notifier support completely from the PCI endpoint framework. Link: https://lore.kernel.org/linux-pci/20230124071158.5503-6-manivannan.sadhasivam@linaro.org Signed-off-by: Manivannan Sadhasivam Signed-off-by: Krzysztof Wilczyński Acked-by: Kishon Vijay Abraham I --- drivers/pci/endpoint/functions/pci-epf-test.c | 33 ++++++++------------------- drivers/pci/endpoint/pci-epc-core.c | 12 ++++++++-- include/linux/pci-epc.h | 8 ------- include/linux/pci-epf.h | 8 ++----- 4 files changed, 22 insertions(+), 39 deletions(-) (limited to 'drivers/pci') diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c index 2fe161747e51..0f9d2ec822ac 100644 --- a/drivers/pci/endpoint/functions/pci-epf-test.c +++ b/drivers/pci/endpoint/functions/pci-epf-test.c @@ -826,30 +826,21 @@ static int pci_epf_test_core_init(struct pci_epf *epf) return 0; } -static const struct pci_epc_event_ops pci_epf_test_event_ops = { - .core_init = pci_epf_test_core_init, -}; - -static int pci_epf_test_notifier(struct notifier_block *nb, unsigned long val, - void *data) +static int pci_epf_test_link_up(struct pci_epf *epf) { - struct pci_epf *epf = container_of(nb, struct pci_epf, nb); struct pci_epf_test *epf_test = epf_get_drvdata(epf); - switch (val) { - case LINK_UP: - queue_delayed_work(kpcitest_workqueue, &epf_test->cmd_handler, - msecs_to_jiffies(1)); - break; - - default: - dev_err(&epf->dev, "Invalid EPF test notifier event\n"); - return NOTIFY_BAD; - } + queue_delayed_work(kpcitest_workqueue, &epf_test->cmd_handler, + msecs_to_jiffies(1)); - return NOTIFY_OK; + return 0; } +static const struct pci_epc_event_ops pci_epf_test_event_ops = { + .core_init = pci_epf_test_core_init, + .link_up = pci_epf_test_link_up, +}; + static int pci_epf_test_alloc_space(struct pci_epf *epf) { struct pci_epf_test *epf_test = epf_get_drvdata(epf); @@ -976,12 +967,8 @@ static int pci_epf_test_bind(struct pci_epf *epf) if (ret) epf_test->dma_supported = false; - if (linkup_notifier || core_init_notifier) { - epf->nb.notifier_call = pci_epf_test_notifier; - pci_epc_register_notifier(epc, &epf->nb); - } else { + if (!linkup_notifier && !core_init_notifier) queue_work(kpcitest_workqueue, &epf_test->cmd_handler.work); - } return 0; } diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c index 7cb9587c6548..c9c3c6b58a9f 100644 --- a/drivers/pci/endpoint/pci-epc-core.c +++ b/drivers/pci/endpoint/pci-epc-core.c @@ -690,10 +690,19 @@ EXPORT_SYMBOL_GPL(pci_epc_remove_epf); */ void pci_epc_linkup(struct pci_epc *epc) { + struct pci_epf *epf; + if (!epc || IS_ERR(epc)) return; - atomic_notifier_call_chain(&epc->notifier, LINK_UP, NULL); + mutex_lock(&epc->list_lock); + list_for_each_entry(epf, &epc->pci_epf, list) { + mutex_lock(&epf->lock); + if (epf->event_ops && epf->event_ops->link_up) + epf->event_ops->link_up(epf); + mutex_unlock(&epf->lock); + } + mutex_unlock(&epc->list_lock); } EXPORT_SYMBOL_GPL(pci_epc_linkup); @@ -788,7 +797,6 @@ __pci_epc_create(struct device *dev, const struct pci_epc_ops *ops, mutex_init(&epc->lock); mutex_init(&epc->list_lock); INIT_LIST_HEAD(&epc->pci_epf); - ATOMIC_INIT_NOTIFIER_HEAD(&epc->notifier); device_initialize(&epc->dev); epc->dev.class = pci_epc_class; diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h index fe729dfe509b..301bb0e53707 100644 --- a/include/linux/pci-epc.h +++ b/include/linux/pci-epc.h @@ -135,7 +135,6 @@ struct pci_epc_mem { * @group: configfs group representing the PCI EPC device * @lock: mutex to protect pci_epc ops * @function_num_map: bitmap to manage physical function number - * @notifier: used to notify EPF of any EPC events (like linkup) */ struct pci_epc { struct device dev; @@ -151,7 +150,6 @@ struct pci_epc { /* mutex to protect against concurrent access of EP controller */ struct mutex lock; unsigned long function_num_map; - struct atomic_notifier_head notifier; }; /** @@ -194,12 +192,6 @@ static inline void *epc_get_drvdata(struct pci_epc *epc) return dev_get_drvdata(&epc->dev); } -static inline int -pci_epc_register_notifier(struct pci_epc *epc, struct notifier_block *nb) -{ - return atomic_notifier_chain_register(&epc->notifier, nb); -} - struct pci_epc * __devm_pci_epc_create(struct device *dev, const struct pci_epc_ops *ops, struct module *owner); diff --git a/include/linux/pci-epf.h b/include/linux/pci-epf.h index fa629c191f00..a215dc8ce693 100644 --- a/include/linux/pci-epf.h +++ b/include/linux/pci-epf.h @@ -17,10 +17,6 @@ struct pci_epf; enum pci_epc_interface_type; -enum pci_notify_event { - LINK_UP, -}; - enum pci_barno { NO_BAR = -1, BAR_0, @@ -74,9 +70,11 @@ struct pci_epf_ops { /** * struct pci_epf_event_ops - Callbacks for capturing the EPC events * @core_init: Callback for the EPC initialization complete event + * @link_up: Callback for the EPC link up event */ struct pci_epc_event_ops { int (*core_init)(struct pci_epf *epf); + int (*link_up)(struct pci_epf *epf); }; /** @@ -134,7 +132,6 @@ struct pci_epf_bar { * @epf_pf: the physical EPF device to which this virtual EPF device is bound * @driver: the EPF driver to which this EPF device is bound * @list: to add pci_epf as a list of PCI endpoint functions to pci_epc - * @nb: notifier block to notify EPF of any EPC events (like linkup) * @lock: mutex to protect pci_epf_ops * @sec_epc: the secondary EPC device to which this EPF device is bound * @sec_epc_list: to add pci_epf as list of PCI endpoint functions to secondary @@ -162,7 +159,6 @@ struct pci_epf { struct pci_epf *epf_pf; struct pci_epf_driver *driver; struct list_head list; - struct notifier_block nb; /* mutex to protect against concurrent access of pci_epf_ops */ struct mutex lock; -- cgit v1.2.3