firmware: arm_scmi: Implement arm,no-completion-irq property

Implement new property arm,no-completion-irq, which sets all SCMI
operation into poll mode. This is meant to work around uncooperative
SCP implementations, which do not generate completion interrupts.
This applies to mbox/shmem based implementations.

With this property set, such implementations which do not generate
interrupts can be interacted with, until they are fixed to generate
interrupts properly.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
Message-Id: <20260117010241.186685-2-marek.vasut+renesas@mailbox.org>
Signed-off-by: Sudeep Holla <sudeep.holla@kernel.org>

diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
index 7c35c95fddbaf8bcccef30e47834bbd34c6660cf..7c9617d080a023c1c28aab60ec02e84294fbfc97 100644 (file)
--- a/drivers/firmware/arm_scmi/common.h
+++ b/drivers/firmware/arm_scmi/common.h
@@ -235,6 +235,9 @@ struct scmi_transport_ops {
  *                   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.
+ * @no_completion_irq: Flag to indicate that this transport has no completion
+ *                    interrupt and has to be polled. This is similar to the
+ *                    force_polling below, except this is set via DT property.
  * @force_polling: Flag to force this whole transport to use SCMI core polling
  *                mechanism instead of completion interrupts even if available.
  * @sync_cmds_completed_on_ret: Flag to indicate that the transport assures
@@ -254,6 +257,7 @@ struct scmi_desc {
        int max_msg;
        int max_msg_size;
        unsigned int atomic_threshold;
+       bool no_completion_irq;
        const bool force_polling;
        const bool sync_cmds_completed_on_ret;
        const bool atomic_enabled;

diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 3e76a3204ba4ff24d22c56e393276a6f7b17aa53..f167194f7cf6789a7aaa74e95861ec9110085d50 100644 (file)
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -2735,6 +2735,7 @@ static int scmi_chan_setup(struct scmi_info *info, struct device_node *of_node,
        cinfo->is_p2a = !tx;
        cinfo->rx_timeout_ms = info->desc->max_rx_timeout_ms;
        cinfo->max_msg_size = info->desc->max_msg_size;
+       cinfo->no_completion_irq = info->desc->no_completion_irq;
 
        /* Create a unique name for this transport device */
        snprintf(name, 32, "__scmi_transport_device_%s_%02X",
@@ -3150,6 +3151,9 @@ static const struct scmi_desc *scmi_transport_setup(struct device *dev)
        if (ret && ret != -EINVAL)
                dev_err(dev, "Malformed arm,max-msg DT property.\n");
 
+       trans->desc.no_completion_irq = of_property_read_bool(dev->of_node,
+                                                             "arm,no-completion-irq");
+
        dev_info(dev,
                 "SCMI max-rx-timeout: %dms / max-msg-size: %dbytes / max-msg: %d\n",
                 trans->desc.max_rx_timeout_ms, trans->desc.max_msg_size,