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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: Jim Quinlan <jim2101024@gmail.com>
[sudeep.holla: added call to reinit_completion, whitespace cleanup, dropped
 irrelavant info in the commit log]
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
This commit is contained in:
Jim Quinlan 2020-12-22 09:56:03 -05:00 committed by Sudeep Holla
parent 99a064fb3a
commit dd820ee21d
1 changed files with 41 additions and 1 deletions
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42
drivers/firmware/arm_scmi/smc.c
View File

@ -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);