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// SPDX-License-Identifier: GPL-2.0
/*
* System Control and Management Interface (SCMI) Message SMC/HVC
* Transport driver
*
* Copyright 2020 NXP
*/
#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"
/**
* struct scmi_smc - Structure representing a SCMI smc transport
*
* @cinfo: SCMI channel info
* @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 {
struct scmi_chan_info *cinfo;
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);
if (!np)
return false;
of_node_put(np);
return true;
}
static int smc_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
bool tx)
{
struct device *cdev = cinfo->dev;
struct scmi_smc *scmi_info;
resource_size_t size;
struct resource res;
struct device_node *np;
u32 func_id;
int ret, irq;
if (!tx)
return -ENODEV;
scmi_info = devm_kzalloc(dev, sizeof(*scmi_info), GFP_KERNEL);
if (!scmi_info)
return -ENOMEM;
np = of_parse_phandle(cdev->of_node, "shmem", 0);
ret = of_address_to_resource(np, 0, &res);
of_node_put(np);
if (ret) {
dev_err(cdev, "failed to get SCMI Tx shared memory\n");
return ret;
}
size = resource_size(&res);
scmi_info->shmem = devm_ioremap(dev, res.start, size);
if (!scmi_info->shmem) {
dev_err(dev, "failed to ioremap SCMI Tx shared memory\n");
return -EADDRNOTAVAIL;
}
ret = of_property_read_u32(dev->of_node, "arm,smc-id", &func_id);
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);
cinfo->transport_info = scmi_info;
return 0;
}
static int smc_chan_free(int id, void *p, void *data)
{
struct scmi_chan_info *cinfo = p;
struct scmi_smc *scmi_info = cinfo->transport_info;
cinfo->transport_info = NULL;
scmi_info->cinfo = NULL;
scmi_free_channel(cinfo, data, id);
return 0;
}
static int smc_send_message(struct scmi_chan_info *cinfo,
struct scmi_xfer *xfer)
{
struct scmi_smc *scmi_info = cinfo->transport_info;
struct arm_smccc_res res;
mutex_lock(&scmi_info->shmem_lock);
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);
/* Only SMCCC_RET_NOT_SUPPORTED is valid error code */
if (res.a0)
return -EOPNOTSUPP;
return 0;
}
static void smc_fetch_response(struct scmi_chan_info *cinfo,
struct scmi_xfer *xfer)
{
struct scmi_smc *scmi_info = cinfo->transport_info;
shmem_fetch_response(scmi_info->shmem, xfer);
}
static bool
smc_poll_done(struct scmi_chan_info *cinfo, struct scmi_xfer *xfer)
{
struct scmi_smc *scmi_info = cinfo->transport_info;
return shmem_poll_done(scmi_info->shmem, xfer);
}
static const struct scmi_transport_ops scmi_smc_ops = {
.chan_available = smc_chan_available,
.chan_setup = smc_chan_setup,
.chan_free = smc_chan_free,
.send_message = smc_send_message,
.fetch_response = smc_fetch_response,
.poll_done = smc_poll_done,
};
const struct scmi_desc scmi_smc_desc = {
.ops = &scmi_smc_ops,
.max_rx_timeout_ms = 30,
.max_msg = 20,
.max_msg_size = 128,
};
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