diff options
Diffstat (limited to 'drivers/firmware/arm_scmi/driver.c')
| -rw-r--r-- | drivers/firmware/arm_scmi/driver.c | 236 |
1 files changed, 192 insertions, 44 deletions
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c index b406b3f78f46..46118300a4d1 100644 --- a/drivers/firmware/arm_scmi/driver.c +++ b/drivers/firmware/arm_scmi/driver.c @@ -131,6 +131,12 @@ struct scmi_protocol_instance { * MAX_PROTOCOLS_IMP elements allocated by the base protocol * @active_protocols: IDR storing device_nodes for protocols actually defined * in the DT and confirmed as implemented by fw. + * @atomic_threshold: Optional system wide DT-configured threshold, expressed + * in microseconds, for atomic operations. + * Only SCMI synchronous commands reported by the platform + * to have an execution latency lesser-equal to the threshold + * should be considered for atomic mode operation: such + * decision is finally left up to the SCMI drivers. * @notify_priv: Pointer to private data structure specific to notifications. * @node: List head * @users: Number of users of this instance @@ -149,6 +155,7 @@ struct scmi_info { struct mutex protocols_mtx; u8 *protocols_imp; struct idr active_protocols; + unsigned int atomic_threshold; void *notify_priv; struct list_head node; int users; @@ -609,6 +616,25 @@ static inline void scmi_clear_channel(struct scmi_info *info, info->desc->ops->clear_channel(cinfo); } +static inline bool is_polling_required(struct scmi_chan_info *cinfo, + struct scmi_info *info) +{ + return cinfo->no_completion_irq || info->desc->force_polling; +} + +static inline bool is_transport_polling_capable(struct scmi_info *info) +{ + return info->desc->ops->poll_done || + info->desc->sync_cmds_completed_on_ret; +} + +static inline bool is_polling_enabled(struct scmi_chan_info *cinfo, + struct scmi_info *info) +{ + return is_polling_required(cinfo, info) && + is_transport_polling_capable(info); +} + static void scmi_handle_notification(struct scmi_chan_info *cinfo, u32 msg_hdr, void *priv) { @@ -629,7 +655,8 @@ static void scmi_handle_notification(struct scmi_chan_info *cinfo, unpack_scmi_header(msg_hdr, &xfer->hdr); if (priv) - xfer->priv = priv; + /* Ensure order between xfer->priv store and following ops */ + smp_store_mb(xfer->priv, priv); info->desc->ops->fetch_notification(cinfo, info->desc->max_msg_size, xfer); scmi_notify(cinfo->handle, xfer->hdr.protocol_id, @@ -661,7 +688,8 @@ static void scmi_handle_response(struct scmi_chan_info *cinfo, xfer->rx.len = info->desc->max_msg_size; if (priv) - xfer->priv = priv; + /* Ensure order between xfer->priv store and following ops */ + smp_store_mb(xfer->priv, priv); info->desc->ops->fetch_response(cinfo, xfer); trace_scmi_rx_done(xfer->transfer_id, xfer->hdr.id, @@ -724,8 +752,6 @@ static void xfer_put(const struct scmi_protocol_handle *ph, __scmi_xfer_put(&info->tx_minfo, xfer); } -#define SCMI_MAX_POLL_TO_NS (100 * NSEC_PER_USEC) - static bool scmi_xfer_done_no_timeout(struct scmi_chan_info *cinfo, struct scmi_xfer *xfer, ktime_t stop) { @@ -741,6 +767,79 @@ static bool scmi_xfer_done_no_timeout(struct scmi_chan_info *cinfo, } /** + * scmi_wait_for_message_response - An helper to group all the possible ways of + * waiting for a synchronous message response. + * + * @cinfo: SCMI channel info + * @xfer: Reference to the transfer being waited for. + * + * Chooses waiting strategy (sleep-waiting vs busy-waiting) depending on + * configuration flags like xfer->hdr.poll_completion. + * + * Return: 0 on Success, error otherwise. + */ +static int scmi_wait_for_message_response(struct scmi_chan_info *cinfo, + struct scmi_xfer *xfer) +{ + struct scmi_info *info = handle_to_scmi_info(cinfo->handle); + struct device *dev = info->dev; + int ret = 0, timeout_ms = info->desc->max_rx_timeout_ms; + + trace_scmi_xfer_response_wait(xfer->transfer_id, xfer->hdr.id, + xfer->hdr.protocol_id, xfer->hdr.seq, + timeout_ms, + xfer->hdr.poll_completion); + + if (xfer->hdr.poll_completion) { + /* + * Real polling is needed only if transport has NOT declared + * itself to support synchronous commands replies. + */ + if (!info->desc->sync_cmds_completed_on_ret) { + /* + * Poll on xfer using transport provided .poll_done(); + * assumes no completion interrupt was available. + */ + ktime_t stop = ktime_add_ms(ktime_get(), timeout_ms); + + spin_until_cond(scmi_xfer_done_no_timeout(cinfo, + xfer, stop)); + if (ktime_after(ktime_get(), stop)) { + dev_err(dev, + "timed out in resp(caller: %pS) - polling\n", + (void *)_RET_IP_); + ret = -ETIMEDOUT; + } + } + + if (!ret) { + unsigned long flags; + + /* + * Do not fetch_response if an out-of-order delayed + * response is being processed. + */ + spin_lock_irqsave(&xfer->lock, flags); + if (xfer->state == SCMI_XFER_SENT_OK) { + info->desc->ops->fetch_response(cinfo, xfer); + xfer->state = SCMI_XFER_RESP_OK; + } + spin_unlock_irqrestore(&xfer->lock, flags); + } + } else { + /* And we wait for the response. */ + if (!wait_for_completion_timeout(&xfer->done, + msecs_to_jiffies(timeout_ms))) { + dev_err(dev, "timed out in resp(caller: %pS)\n", + (void *)_RET_IP_); + ret = -ETIMEDOUT; + } + } + + return ret; +} + +/** * do_xfer() - Do one transfer * * @ph: Pointer to SCMI protocol handle @@ -754,18 +853,26 @@ static int do_xfer(const struct scmi_protocol_handle *ph, struct scmi_xfer *xfer) { int ret; - int timeout; const struct scmi_protocol_instance *pi = ph_to_pi(ph); struct scmi_info *info = handle_to_scmi_info(pi->handle); struct device *dev = info->dev; struct scmi_chan_info *cinfo; - if (xfer->hdr.poll_completion && !info->desc->ops->poll_done) { + /* Check for polling request on custom command xfers at first */ + if (xfer->hdr.poll_completion && !is_transport_polling_capable(info)) { dev_warn_once(dev, "Polling mode is not supported by transport.\n"); return -EINVAL; } + cinfo = idr_find(&info->tx_idr, pi->proto->id); + if (unlikely(!cinfo)) + return -EINVAL; + + /* True ONLY if also supported by transport. */ + if (is_polling_enabled(cinfo, info)) + xfer->hdr.poll_completion = true; + /* * Initialise protocol id now from protocol handle to avoid it being * overridden by mistake (or malice) by the protocol code mangling with @@ -774,10 +881,6 @@ static int do_xfer(const struct scmi_protocol_handle *ph, xfer->hdr.protocol_id = pi->proto->id; reinit_completion(&xfer->done); - cinfo = idr_find(&info->tx_idr, xfer->hdr.protocol_id); - if (unlikely(!cinfo)) - return -EINVAL; - trace_scmi_xfer_begin(xfer->transfer_id, xfer->hdr.id, xfer->hdr.protocol_id, xfer->hdr.seq, xfer->hdr.poll_completion); @@ -798,41 +901,12 @@ static int do_xfer(const struct scmi_protocol_handle *ph, return ret; } - if (xfer->hdr.poll_completion) { - ktime_t stop = ktime_add_ns(ktime_get(), SCMI_MAX_POLL_TO_NS); - - spin_until_cond(scmi_xfer_done_no_timeout(cinfo, xfer, stop)); - if (ktime_before(ktime_get(), stop)) { - unsigned long flags; - - /* - * Do not fetch_response if an out-of-order delayed - * response is being processed. - */ - spin_lock_irqsave(&xfer->lock, flags); - if (xfer->state == SCMI_XFER_SENT_OK) { - info->desc->ops->fetch_response(cinfo, xfer); - xfer->state = SCMI_XFER_RESP_OK; - } - spin_unlock_irqrestore(&xfer->lock, flags); - } else { - ret = -ETIMEDOUT; - } - } else { - /* And we wait for the response. */ - timeout = msecs_to_jiffies(info->desc->max_rx_timeout_ms); - if (!wait_for_completion_timeout(&xfer->done, timeout)) { - dev_err(dev, "timed out in resp(caller: %pS)\n", - (void *)_RET_IP_); - ret = -ETIMEDOUT; - } - } - + ret = scmi_wait_for_message_response(cinfo, xfer); if (!ret && xfer->hdr.status) ret = scmi_to_linux_errno(xfer->hdr.status); if (info->desc->ops->mark_txdone) - info->desc->ops->mark_txdone(cinfo, ret); + info->desc->ops->mark_txdone(cinfo, ret, xfer); trace_scmi_xfer_end(xfer->transfer_id, xfer->hdr.id, xfer->hdr.protocol_id, xfer->hdr.seq, ret); @@ -858,6 +932,20 @@ static void reset_rx_to_maxsz(const struct scmi_protocol_handle *ph, * @ph: Pointer to SCMI protocol handle * @xfer: Transfer to initiate and wait for response * + * Using asynchronous commands in atomic/polling mode should be avoided since + * it could cause long busy-waiting here, so ignore polling for the delayed + * response and WARN if it was requested for this command transaction since + * upper layers should refrain from issuing such kind of requests. + * + * The only other option would have been to refrain from using any asynchronous + * command even if made available, when an atomic transport is detected, and + * instead forcibly use the synchronous version (thing that can be easily + * attained at the protocol layer), but this would also have led to longer + * stalls of the channel for synchronous commands and possibly timeouts. + * (in other words there is usually a good reason if a platform provides an + * asynchronous version of a command and we should prefer to use it...just not + * when using atomic/polling mode) + * * Return: -ETIMEDOUT in case of no delayed response, if transmit error, * return corresponding error, else if all goes well, return 0. */ @@ -869,12 +957,24 @@ static int do_xfer_with_response(const struct scmi_protocol_handle *ph, xfer->async_done = &async_response; + /* + * Delayed responses should not be polled, so an async command should + * not have been used when requiring an atomic/poll context; WARN and + * perform instead a sleeping wait. + * (Note Async + IgnoreDelayedResponses are sent via do_xfer) + */ + WARN_ON_ONCE(xfer->hdr.poll_completion); + ret = do_xfer(ph, xfer); if (!ret) { - if (!wait_for_completion_timeout(xfer->async_done, timeout)) + if (!wait_for_completion_timeout(xfer->async_done, timeout)) { + dev_err(ph->dev, + "timed out in delayed resp(caller: %pS)\n", + (void *)_RET_IP_); ret = -ETIMEDOUT; - else if (xfer->hdr.status) + } else if (xfer->hdr.status) { ret = scmi_to_linux_errno(xfer->hdr.status); + } } xfer->async_done = NULL; @@ -1308,6 +1408,29 @@ static void scmi_devm_protocol_put(struct scmi_device *sdev, u8 protocol_id) WARN_ON(ret); } +/** + * scmi_is_transport_atomic - Method to check if underlying transport for an + * SCMI instance is configured as atomic. + * + * @handle: A reference to the SCMI platform instance. + * @atomic_threshold: An optional return value for the system wide currently + * configured threshold for atomic operations. + * + * Return: True if transport is configured as atomic + */ +static bool scmi_is_transport_atomic(const struct scmi_handle *handle, + unsigned int *atomic_threshold) +{ + bool ret; + struct scmi_info *info = handle_to_scmi_info(handle); + + ret = info->desc->atomic_enabled && is_transport_polling_capable(info); + if (ret && atomic_threshold) + *atomic_threshold = info->atomic_threshold; + + return ret; +} + static inline struct scmi_handle *scmi_handle_get_from_info_unlocked(struct scmi_info *info) { @@ -1499,6 +1622,16 @@ static int scmi_chan_setup(struct scmi_info *info, struct device *dev, if (ret) return ret; + if (tx && is_polling_required(cinfo, info)) { + if (is_transport_polling_capable(info)) + dev_info(dev, + "Enabled polling mode TX channel - prot_id:%d\n", + prot_id); + else + dev_warn(dev, + "Polling mode NOT supported by transport.\n"); + } + idr_alloc: ret = idr_alloc(idr, cinfo, prot_id, prot_id + 1, GFP_KERNEL); if (ret != prot_id) { @@ -1836,6 +1969,14 @@ static int scmi_probe(struct platform_device *pdev) handle->devm_protocol_get = scmi_devm_protocol_get; handle->devm_protocol_put = scmi_devm_protocol_put; + /* System wide atomic threshold for atomic ops .. if any */ + if (!of_property_read_u32(np, "atomic-threshold-us", + &info->atomic_threshold)) + dev_info(dev, + "SCMI System wide atomic threshold set to %d us\n", + info->atomic_threshold); + handle->is_transport_atomic = scmi_is_transport_atomic; + if (desc->ops->link_supplier) { ret = desc->ops->link_supplier(dev); if (ret) @@ -1853,6 +1994,10 @@ static int scmi_probe(struct platform_device *pdev) if (scmi_notification_init(handle)) dev_err(dev, "SCMI Notifications NOT available.\n"); + if (info->desc->atomic_enabled && !is_transport_polling_capable(info)) + dev_err(dev, + "Transport is not polling capable. Atomic mode not supported.\n"); + /* * Trigger SCMI Base protocol initialization. * It's mandatory and won't be ever released/deinit until the @@ -1994,6 +2139,9 @@ static const struct of_device_id scmi_of_match[] = { #ifdef CONFIG_ARM_SCMI_TRANSPORT_MAILBOX { .compatible = "arm,scmi", .data = &scmi_mailbox_desc }, #endif +#ifdef CONFIG_ARM_SCMI_TRANSPORT_OPTEE + { .compatible = "linaro,scmi-optee", .data = &scmi_optee_desc }, +#endif #ifdef CONFIG_ARM_SCMI_TRANSPORT_SMC { .compatible = "arm,scmi-smc", .data = &scmi_smc_desc}, #endif @@ -2112,7 +2260,7 @@ static void __exit scmi_driver_exit(void) } module_exit(scmi_driver_exit); -MODULE_ALIAS("platform: arm-scmi"); +MODULE_ALIAS("platform:arm-scmi"); MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>"); MODULE_DESCRIPTION("ARM SCMI protocol driver"); MODULE_LICENSE("GPL v2"); |