From 3f4071cbd2063b917486d1047a4da47718215fee Mon Sep 17 00:00:00 2001 From: Cristian Marussi Date: Fri, 28 Oct 2022 15:08:26 +0100 Subject: [PATCH 1/6] firmware: arm_scmi: Cleanup the core driver removal callback MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Platform drivers .remove callbacks are not supposed to fail and report errors. Such errors are indeed ignored by the core platform drivers and the driver unbind process is anyway completed. The SCMI core platform driver as it is now, instead, bails out reporting an error in case of an explicit unbind request. Fix the removal path by adding proper device links between the core SCMI device and the SCMI protocol devices so that a full SCMI stack unbind is triggered when the core driver is removed. The remove process does not bail out anymore on the anomalous conditions triggered by an explicit unbind but the user is still warned. Reported-by: Uwe Kleine-König Signed-off-by: Cristian Marussi Link: https://lore.kernel.org/r/20221028140833.280091-1-cristian.marussi@arm.com Signed-off-by: Sudeep Holla --- drivers/firmware/arm_scmi/bus.c | 11 +++++++++++ drivers/firmware/arm_scmi/common.h | 1 + drivers/firmware/arm_scmi/driver.c | 31 ++++++++++++++++++------------ 3 files changed, 31 insertions(+), 12 deletions(-) diff --git a/drivers/firmware/arm_scmi/bus.c b/drivers/firmware/arm_scmi/bus.c index d4e23101448a..35bb70724d44 100644 --- a/drivers/firmware/arm_scmi/bus.c +++ b/drivers/firmware/arm_scmi/bus.c @@ -216,9 +216,20 @@ void scmi_device_destroy(struct scmi_device *scmi_dev) device_unregister(&scmi_dev->dev); } +void scmi_device_link_add(struct device *consumer, struct device *supplier) +{ + struct device_link *link; + + link = device_link_add(consumer, supplier, DL_FLAG_AUTOREMOVE_CONSUMER); + + WARN_ON(!link); +} + void scmi_set_handle(struct scmi_device *scmi_dev) { scmi_dev->handle = scmi_handle_get(&scmi_dev->dev); + if (scmi_dev->handle) + scmi_device_link_add(&scmi_dev->dev, scmi_dev->handle->dev); } int scmi_protocol_register(const struct scmi_protocol *proto) diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h index 61aba7447c32..9b87b5b69535 100644 --- a/drivers/firmware/arm_scmi/common.h +++ b/drivers/firmware/arm_scmi/common.h @@ -97,6 +97,7 @@ static inline void unpack_scmi_header(u32 msg_hdr, struct scmi_msg_hdr *hdr) struct scmi_revision_info * scmi_revision_area_get(const struct scmi_protocol_handle *ph); int scmi_handle_put(const struct scmi_handle *handle); +void scmi_device_link_add(struct device *consumer, struct device *supplier); struct scmi_handle *scmi_handle_get(struct device *dev); void scmi_set_handle(struct scmi_device *scmi_dev); void scmi_setup_protocol_implemented(const struct scmi_protocol_handle *ph, diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c index 609ebedee9cb..7e19b6055d75 100644 --- a/drivers/firmware/arm_scmi/driver.c +++ b/drivers/firmware/arm_scmi/driver.c @@ -2273,10 +2273,16 @@ int scmi_protocol_device_request(const struct scmi_device_id *id_table) sdev = scmi_get_protocol_device(child, info, id_table->protocol_id, id_table->name); - /* Set handle if not already set: device existed */ - if (sdev && !sdev->handle) - sdev->handle = - scmi_handle_get_from_info_unlocked(info); + if (sdev) { + /* Set handle if not already set: device existed */ + if (!sdev->handle) + sdev->handle = + scmi_handle_get_from_info_unlocked(info); + /* Relink consumer and suppliers */ + if (sdev->handle) + scmi_device_link_add(&sdev->dev, + sdev->handle->dev); + } } else { dev_err(info->dev, "Failed. SCMI protocol %d not active.\n", @@ -2475,20 +2481,17 @@ void scmi_free_channel(struct scmi_chan_info *cinfo, struct idr *idr, int id) static int scmi_remove(struct platform_device *pdev) { - int ret = 0, id; + int ret, id; struct scmi_info *info = platform_get_drvdata(pdev); struct device_node *child; mutex_lock(&scmi_list_mutex); if (info->users) - ret = -EBUSY; - else - list_del(&info->node); + dev_warn(&pdev->dev, + "Still active SCMI users will be forcibly unbound.\n"); + list_del(&info->node); mutex_unlock(&scmi_list_mutex); - if (ret) - return ret; - scmi_notification_exit(&info->handle); mutex_lock(&info->protocols_mtx); @@ -2500,7 +2503,11 @@ static int scmi_remove(struct platform_device *pdev) idr_destroy(&info->active_protocols); /* Safe to free channels since no more users */ - return scmi_cleanup_txrx_channels(info); + ret = scmi_cleanup_txrx_channels(info); + if (ret) + dev_warn(&pdev->dev, "Failed to cleanup SCMI channels.\n"); + + return 0; } static ssize_t protocol_version_show(struct device *dev, From fd96fbc8fad35d6b1872c90df8a2f5d721f14d91 Mon Sep 17 00:00:00 2001 From: Cristian Marussi Date: Fri, 28 Oct 2022 15:08:27 +0100 Subject: [PATCH 2/6] firmware: arm_scmi: Suppress the driver's bind attributes Suppress the capability to unbind the core SCMI driver since all the SCMI stack protocol drivers depend on it. Fixes: aa4f886f3893 ("firmware: arm_scmi: add basic driver infrastructure for SCMI") Signed-off-by: Cristian Marussi Link: https://lore.kernel.org/r/20221028140833.280091-2-cristian.marussi@arm.com Signed-off-by: Sudeep Holla --- drivers/firmware/arm_scmi/driver.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c index 7e19b6055d75..94be633b55a0 100644 --- a/drivers/firmware/arm_scmi/driver.c +++ b/drivers/firmware/arm_scmi/driver.c @@ -2578,6 +2578,7 @@ MODULE_DEVICE_TABLE(of, scmi_of_match); static struct platform_driver scmi_driver = { .driver = { .name = "arm-scmi", + .suppress_bind_attrs = true, .of_match_table = scmi_of_match, .dev_groups = versions_groups, }, From 59172b212ec0dbb97ceb5671d912e6e61fa802d5 Mon Sep 17 00:00:00 2001 From: Cristian Marussi Date: Fri, 28 Oct 2022 15:08:28 +0100 Subject: [PATCH 3/6] firmware: arm_scmi: Make tx_prepare time out eventually SCMI transports based on shared memory, at start of transmissions, have to wait for the shared Tx channel area to be eventually freed by the SCMI platform before accessing the channel. In fact the channel is owned by the SCMI platform until marked as free by the platform itself and, as such, cannot be used by the agent until relinquished. As a consequence a badly misbehaving SCMI platform firmware could lock the channel indefinitely and make the kernel side SCMI stack loop forever waiting for such channel to be freed, possibly hanging the whole boot sequence. Add a timeout to the existent Tx waiting spin-loop so that, when the system ends up in this situation, the SCMI stack can at least bail-out, nosily warn the user, and abort the transmission. Reported-by: YaxiongTian Suggested-by: YaxiongTian Cc: Vincent Guittot Cc: Etienne Carriere Cc: Florian Fainelli Signed-off-by: Cristian Marussi Link: https://lore.kernel.org/r/20221028140833.280091-3-cristian.marussi@arm.com Signed-off-by: Sudeep Holla --- drivers/firmware/arm_scmi/common.h | 4 +++- drivers/firmware/arm_scmi/driver.c | 1 + drivers/firmware/arm_scmi/mailbox.c | 2 +- drivers/firmware/arm_scmi/optee.c | 2 +- drivers/firmware/arm_scmi/shmem.c | 31 +++++++++++++++++++++++++---- drivers/firmware/arm_scmi/smc.c | 2 +- 6 files changed, 34 insertions(+), 8 deletions(-) diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h index 9b87b5b69535..a1c0154c31c6 100644 --- a/drivers/firmware/arm_scmi/common.h +++ b/drivers/firmware/arm_scmi/common.h @@ -118,6 +118,7 @@ void scmi_protocol_release(const struct scmi_handle *handle, u8 protocol_id); * * @dev: Reference to device in the SCMI hierarchy corresponding to this * channel + * @rx_timeout_ms: The configured RX timeout in milliseconds. * @handle: Pointer to SCMI entity handle * @no_completion_irq: Flag to indicate that this channel has no completion * interrupt mechanism for synchronous commands. @@ -127,6 +128,7 @@ void scmi_protocol_release(const struct scmi_handle *handle, u8 protocol_id); */ struct scmi_chan_info { struct device *dev; + unsigned int rx_timeout_ms; struct scmi_handle *handle; bool no_completion_irq; void *transport_info; @@ -233,7 +235,7 @@ void scmi_free_channel(struct scmi_chan_info *cinfo, struct idr *idr, int id); struct scmi_shared_mem; void shmem_tx_prepare(struct scmi_shared_mem __iomem *shmem, - struct scmi_xfer *xfer); + struct scmi_xfer *xfer, struct scmi_chan_info *cinfo); u32 shmem_read_header(struct scmi_shared_mem __iomem *shmem); void shmem_fetch_response(struct scmi_shared_mem __iomem *shmem, struct scmi_xfer *xfer); diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c index 94be633b55a0..985775f210f9 100644 --- a/drivers/firmware/arm_scmi/driver.c +++ b/drivers/firmware/arm_scmi/driver.c @@ -2013,6 +2013,7 @@ static int scmi_chan_setup(struct scmi_info *info, struct device *dev, return -ENOMEM; cinfo->dev = dev; + cinfo->rx_timeout_ms = info->desc->max_rx_timeout_ms; ret = info->desc->ops->chan_setup(cinfo, info->dev, tx); if (ret) diff --git a/drivers/firmware/arm_scmi/mailbox.c b/drivers/firmware/arm_scmi/mailbox.c index 08ff4d110beb..1e40cb035044 100644 --- a/drivers/firmware/arm_scmi/mailbox.c +++ b/drivers/firmware/arm_scmi/mailbox.c @@ -36,7 +36,7 @@ static void tx_prepare(struct mbox_client *cl, void *m) { struct scmi_mailbox *smbox = client_to_scmi_mailbox(cl); - shmem_tx_prepare(smbox->shmem, m); + shmem_tx_prepare(smbox->shmem, m, smbox->cinfo); } static void rx_callback(struct mbox_client *cl, void *m) diff --git a/drivers/firmware/arm_scmi/optee.c b/drivers/firmware/arm_scmi/optee.c index f42dad997ac9..2a7aeab40e54 100644 --- a/drivers/firmware/arm_scmi/optee.c +++ b/drivers/firmware/arm_scmi/optee.c @@ -498,7 +498,7 @@ static int scmi_optee_send_message(struct scmi_chan_info *cinfo, msg_tx_prepare(channel->req.msg, xfer); ret = invoke_process_msg_channel(channel, msg_command_size(xfer)); } else { - shmem_tx_prepare(channel->req.shmem, xfer); + shmem_tx_prepare(channel->req.shmem, xfer, cinfo); ret = invoke_process_smt_channel(channel); } diff --git a/drivers/firmware/arm_scmi/shmem.c b/drivers/firmware/arm_scmi/shmem.c index 0e3eaea5d852..1dfe534b8518 100644 --- a/drivers/firmware/arm_scmi/shmem.c +++ b/drivers/firmware/arm_scmi/shmem.c @@ -5,10 +5,13 @@ * Copyright (C) 2019 ARM Ltd. */ +#include #include #include #include +#include + #include "common.h" /* @@ -30,16 +33,36 @@ struct scmi_shared_mem { }; void shmem_tx_prepare(struct scmi_shared_mem __iomem *shmem, - struct scmi_xfer *xfer) + struct scmi_xfer *xfer, struct scmi_chan_info *cinfo) { + ktime_t stop; + /* * Ideally channel must be free by now unless OS timeout last * request and platform continued to process the same, wait * until it releases the shared memory, otherwise we may endup - * overwriting its response with new message payload or vice-versa + * overwriting its response with new message payload or vice-versa. + * Giving up anyway after twice the expected channel timeout so as + * not to bail-out on intermittent issues where the platform is + * occasionally a bit slower to answer. + * + * Note that after a timeout is detected we bail-out and carry on but + * the transport functionality is probably permanently compromised: + * this is just to ease debugging and avoid complete hangs on boot + * due to a misbehaving SCMI firmware. */ - spin_until_cond(ioread32(&shmem->channel_status) & - SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE); + stop = ktime_add_ms(ktime_get(), 2 * cinfo->rx_timeout_ms); + spin_until_cond((ioread32(&shmem->channel_status) & + SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE) || + ktime_after(ktime_get(), stop)); + if (!(ioread32(&shmem->channel_status) & + SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE)) { + WARN_ON_ONCE(1); + dev_err(cinfo->dev, + "Timeout waiting for a free TX channel !\n"); + return; + } + /* Mark channel busy + clear error */ iowrite32(0x0, &shmem->channel_status); iowrite32(xfer->hdr.poll_completion ? 0 : SCMI_SHMEM_FLAG_INTR_ENABLED, diff --git a/drivers/firmware/arm_scmi/smc.c b/drivers/firmware/arm_scmi/smc.c index 745acfdd0b3d..87a7b13cf868 100644 --- a/drivers/firmware/arm_scmi/smc.c +++ b/drivers/firmware/arm_scmi/smc.c @@ -188,7 +188,7 @@ static int smc_send_message(struct scmi_chan_info *cinfo, */ smc_channel_lock_acquire(scmi_info, xfer); - shmem_tx_prepare(scmi_info->shmem, xfer); + shmem_tx_prepare(scmi_info->shmem, xfer, cinfo); arm_smccc_1_1_invoke(scmi_info->func_id, 0, 0, 0, 0, 0, 0, 0, &res); From be9ba1f7f9e0b565b19f4294f5871da9d654bc6d Mon Sep 17 00:00:00 2001 From: Cristian Marussi Date: Fri, 28 Oct 2022 15:08:29 +0100 Subject: [PATCH 4/6] firmware: arm_scmi: Make Rx chan_setup fail on memory errors SCMI Rx channels are optional and they can fail to be setup when not present but anyway channels setup routines must bail-out on memory errors. Make channels setup, and related probing, fail when memory errors are reported on Rx channels. Fixes: 5c8a47a5a91d ("firmware: arm_scmi: Make scmi core independent of the transport type") Signed-off-by: Cristian Marussi Link: https://lore.kernel.org/r/20221028140833.280091-4-cristian.marussi@arm.com Signed-off-by: Sudeep Holla --- drivers/firmware/arm_scmi/driver.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c index 985775f210f9..f818d00bb2c6 100644 --- a/drivers/firmware/arm_scmi/driver.c +++ b/drivers/firmware/arm_scmi/driver.c @@ -2045,8 +2045,12 @@ scmi_txrx_setup(struct scmi_info *info, struct device *dev, int prot_id) { int ret = scmi_chan_setup(info, dev, prot_id, true); - if (!ret) /* Rx is optional, hence no error check */ - scmi_chan_setup(info, dev, prot_id, false); + if (!ret) { + /* Rx is optional, report only memory errors */ + ret = scmi_chan_setup(info, dev, prot_id, false); + if (ret && ret != -ENOMEM) + ret = 0; + } return ret; } From 5ffc1c4cb896f8d2cf10309422da3633a616d60f Mon Sep 17 00:00:00 2001 From: Cristian Marussi Date: Fri, 28 Oct 2022 15:08:30 +0100 Subject: [PATCH 5/6] firmware: arm_scmi: Fix devres allocation device in virtio transport SCMI virtio transport device managed allocations must use the main platform device in devres operations instead of the channel devices. Cc: Peter Hilber Fixes: 46abe13b5e3d ("firmware: arm_scmi: Add virtio transport") Signed-off-by: Cristian Marussi Link: https://lore.kernel.org/r/20221028140833.280091-5-cristian.marussi@arm.com Signed-off-by: Sudeep Holla --- drivers/firmware/arm_scmi/virtio.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/firmware/arm_scmi/virtio.c b/drivers/firmware/arm_scmi/virtio.c index 14709dbc96a1..36b7686843a4 100644 --- a/drivers/firmware/arm_scmi/virtio.c +++ b/drivers/firmware/arm_scmi/virtio.c @@ -444,12 +444,12 @@ static int virtio_chan_setup(struct scmi_chan_info *cinfo, struct device *dev, for (i = 0; i < vioch->max_msg; i++) { struct scmi_vio_msg *msg; - msg = devm_kzalloc(cinfo->dev, sizeof(*msg), GFP_KERNEL); + msg = devm_kzalloc(dev, sizeof(*msg), GFP_KERNEL); if (!msg) return -ENOMEM; if (tx) { - msg->request = devm_kzalloc(cinfo->dev, + msg->request = devm_kzalloc(dev, VIRTIO_SCMI_MAX_PDU_SIZE, GFP_KERNEL); if (!msg->request) @@ -458,7 +458,7 @@ static int virtio_chan_setup(struct scmi_chan_info *cinfo, struct device *dev, refcount_set(&msg->users, 1); } - msg->input = devm_kzalloc(cinfo->dev, VIRTIO_SCMI_MAX_PDU_SIZE, + msg->input = devm_kzalloc(dev, VIRTIO_SCMI_MAX_PDU_SIZE, GFP_KERNEL); if (!msg->input) return -ENOMEM; From 1eff6929aff594fba3182660f7b6213ec0ceda0c Mon Sep 17 00:00:00 2001 From: Cristian Marussi Date: Fri, 28 Oct 2022 15:08:31 +0100 Subject: [PATCH 6/6] firmware: arm_scmi: Fix deferred_tx_wq release on error paths Use devres to allocate the dedicated deferred_tx_wq polling workqueue so as to automatically trigger the proper resource release on error path. Reported-by: Dan Carpenter Fixes: 5a3b7185c47c ("firmware: arm_scmi: Add atomic mode support to virtio transport") Signed-off-by: Cristian Marussi Link: https://lore.kernel.org/r/20221028140833.280091-6-cristian.marussi@arm.com Signed-off-by: Sudeep Holla --- drivers/firmware/arm_scmi/virtio.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/drivers/firmware/arm_scmi/virtio.c b/drivers/firmware/arm_scmi/virtio.c index 36b7686843a4..33c9b81a55cd 100644 --- a/drivers/firmware/arm_scmi/virtio.c +++ b/drivers/firmware/arm_scmi/virtio.c @@ -148,7 +148,6 @@ static void scmi_vio_channel_cleanup_sync(struct scmi_vio_channel *vioch) { unsigned long flags; DECLARE_COMPLETION_ONSTACK(vioch_shutdown_done); - void *deferred_wq = NULL; /* * Prepare to wait for the last release if not already released @@ -162,16 +161,11 @@ static void scmi_vio_channel_cleanup_sync(struct scmi_vio_channel *vioch) vioch->shutdown_done = &vioch_shutdown_done; virtio_break_device(vioch->vqueue->vdev); - if (!vioch->is_rx && vioch->deferred_tx_wq) { - deferred_wq = vioch->deferred_tx_wq; + if (!vioch->is_rx && vioch->deferred_tx_wq) /* Cannot be kicked anymore after this...*/ vioch->deferred_tx_wq = NULL; - } spin_unlock_irqrestore(&vioch->lock, flags); - if (deferred_wq) - destroy_workqueue(deferred_wq); - scmi_vio_channel_release(vioch); /* Let any possibly concurrent RX path release the channel */ @@ -416,6 +410,11 @@ static bool virtio_chan_available(struct device *dev, int idx) return vioch && !vioch->cinfo; } +static void scmi_destroy_tx_workqueue(void *deferred_tx_wq) +{ + destroy_workqueue(deferred_tx_wq); +} + static int virtio_chan_setup(struct scmi_chan_info *cinfo, struct device *dev, bool tx) { @@ -430,6 +429,8 @@ static int virtio_chan_setup(struct scmi_chan_info *cinfo, struct device *dev, /* Setup a deferred worker for polling. */ if (tx && !vioch->deferred_tx_wq) { + int ret; + vioch->deferred_tx_wq = alloc_workqueue(dev_name(&scmi_vdev->dev), WQ_UNBOUND | WQ_FREEZABLE | WQ_SYSFS, @@ -437,6 +438,11 @@ static int virtio_chan_setup(struct scmi_chan_info *cinfo, struct device *dev, if (!vioch->deferred_tx_wq) return -ENOMEM; + ret = devm_add_action_or_reset(dev, scmi_destroy_tx_workqueue, + vioch->deferred_tx_wq); + if (ret) + return ret; + INIT_WORK(&vioch->deferred_tx_work, scmi_vio_deferred_tx_worker); }