Commit dd820ee2 authored by Jim Quinlan's avatar Jim Quinlan Committed by Sudeep Holla
Browse files

firmware: arm_scmi: Augment SMC/HVC to allow optional interrupt 

The SMC/HVC SCMI transport is modified to allow the completion of an
SCMI message to be indicated by an interrupt rather than the return of
the smc/hvc call. This accommodates the existing behavior of the
BrcmSTB SCMI "platform".

Link: https://lore.kernel.org/r/20201222145603.40192-3-jim2101024@gmail.com


Signed-off-by: default avatarJim Quinlan <jim2101024@gmail.com>
[sudeep.holla: added call to reinit_completion, whitespace cleanup, dropped
 irrelavant info in the commit log]
Signed-off-by: default avatarSudeep Holla <sudeep.holla@arm.com>
parent 99a064fb

drivers/firmware/arm_scmi/smc.c

+41 −1
Original line number Diff line number Diff line
@@ -9,9 +9,11 @@ 
#include <linux/arm-smccc.h>

#include <linux/device.h>

#include <linux/err.h>

#include <linux/interrupt.h>

#include <linux/mutex.h>

#include <linux/of.h>

#include <linux/of_address.h>

#include <linux/of_irq.h>

#include <linux/slab.h>



#include "common.h"
@@ -23,6 +25,8 @@ 
 * @shmem: Transmit/Receive shared memory area

 * @shmem_lock: Lock to protect access to Tx/Rx shared memory area

 * @func_id: smc/hvc call function id

 * @irq: Optional; employed when platforms indicates msg completion by intr.

 * @tx_complete: Optional, employed only when irq is valid.

 */



struct scmi_smc {
@@ -30,8 +34,19 @@ struct scmi_smc { 
	struct scmi_shared_mem __iomem *shmem;

	struct mutex shmem_lock;

	u32 func_id;

	int irq;

	struct completion tx_complete;

};



static irqreturn_t smc_msg_done_isr(int irq, void *data)

{

	struct scmi_smc *scmi_info = data;



	complete(&scmi_info->tx_complete);



	return IRQ_HANDLED;

}



static bool smc_chan_available(struct device *dev, int idx)

{

	struct device_node *np = of_parse_phandle(dev->of_node, "shmem", 0);
@@ -51,7 +66,7 @@ static int smc_chan_setup(struct scmi_chan_info *cinfo, struct device *dev, 
	struct resource res;

	struct device_node *np;

	u32 func_id;

	int ret;

	int ret, irq;



	if (!tx)

		return -ENODEV;
@@ -79,6 +94,24 @@ static int smc_chan_setup(struct scmi_chan_info *cinfo, struct device *dev, 
	if (ret < 0)

		return ret;



	/*

	 * If there is an interrupt named "a2p", then the service and

	 * completion of a message is signaled by an interrupt rather than by

	 * the return of the SMC call.

	 */

	irq = of_irq_get_byname(cdev->of_node, "a2p");

	if (irq > 0) {

		ret = devm_request_irq(dev, irq, smc_msg_done_isr,

				       IRQF_NO_SUSPEND,

				       dev_name(dev), scmi_info);

		if (ret) {

			dev_err(dev, "failed to setup SCMI smc irq\n");

			return ret;

		}

		init_completion(&scmi_info->tx_complete);

		scmi_info->irq = irq;

	}



	scmi_info->func_id = func_id;

	scmi_info->cinfo = cinfo;

	mutex_init(&scmi_info->shmem_lock);
@@ -110,7 +143,14 @@ static int smc_send_message(struct scmi_chan_info *cinfo, 


	shmem_tx_prepare(scmi_info->shmem, xfer);



	if (scmi_info->irq)

		reinit_completion(&scmi_info->tx_complete);



	arm_smccc_1_1_invoke(scmi_info->func_id, 0, 0, 0, 0, 0, 0, 0, &res);



	if (scmi_info->irq)

		wait_for_completion(&scmi_info->tx_complete);



	scmi_rx_callback(scmi_info->cinfo, shmem_read_header(scmi_info->shmem));



	mutex_unlock(&scmi_info->shmem_lock);