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// SPDX-License-Identifier: GPL-2.0-or-later
#include <linux/cleanup.h>
#include <linux/completion.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/pse-pd/pse.h>
#include <linux/serdev.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include "realtek-pse-mcu.h"
#define RTPSE_MCU_UART_BAUD_DEFAULT 19200
#define RTPSE_MCU_UART_TX_TIMEOUT msecs_to_jiffies(100)
#define RTPSE_MCU_UART_RX_TIMEOUT msecs_to_jiffies(RTPSE_MCU_RESPONSE_MAX_MS)
struct rtpse_mcu_uart {
struct rtpse_mcu_ctrl pse;
struct serdev_device *serdev;
struct completion rx_done;
spinlock_t rx_lock; /* protects rx_buf and rx_len */
size_t rx_len;
u8 rx_buf[RTPSE_MCU_MSG_SIZE];
};
#define to_rtpse_mcu_uart(p) container_of(p, struct rtpse_mcu_uart, pse)
/*
* No framing is done here: a glitched frame costs one transaction, then
* the next _send re-frames from rx_len 0. Resync works by returning count
* (not take), dropping any overflow so serdev keeps no leftover to bleed
* into the next frame.
*/
static size_t rtpse_mcu_uart_receive(struct serdev_device *serdev,
const u8 *buf, size_t count)
{
struct rtpse_mcu_uart *ctx = serdev_device_get_drvdata(serdev);
size_t take;
scoped_guard(spinlock_irqsave, &ctx->rx_lock) {
take = min(count, sizeof(ctx->rx_buf) - ctx->rx_len);
if (take) {
memcpy(ctx->rx_buf + ctx->rx_len, buf, take);
ctx->rx_len += take;
if (ctx->rx_len == sizeof(ctx->rx_buf))
complete(&ctx->rx_done);
}
}
/* consume all to avoid desync/misalignment */
return count;
}
static const struct serdev_device_ops rtpse_mcu_uart_serdev_ops = {
.receive_buf = rtpse_mcu_uart_receive,
.write_wakeup = serdev_device_write_wakeup,
};
static int rtpse_mcu_uart_send(struct rtpse_mcu_ctrl *pse, const struct rtpse_mcu_msg *req)
{
struct rtpse_mcu_uart *ctx = to_rtpse_mcu_uart(pse);
int written;
/* clear any leftover rx state before transmitting */
scoped_guard(spinlock_irqsave, &ctx->rx_lock) {
reinit_completion(&ctx->rx_done);
ctx->rx_len = 0;
}
written = serdev_device_write(ctx->serdev, (const u8 *)req, sizeof(*req),
RTPSE_MCU_UART_TX_TIMEOUT);
if (written < 0)
return written;
if (written != sizeof(*req))
return -EIO;
return 0;
}
static int rtpse_mcu_uart_recv(struct rtpse_mcu_ctrl *pse,
const struct rtpse_mcu_msg *req,
struct rtpse_mcu_msg *resp)
{
struct rtpse_mcu_uart *ctx = to_rtpse_mcu_uart(pse);
if (!wait_for_completion_timeout(&ctx->rx_done, RTPSE_MCU_UART_RX_TIMEOUT))
return -ETIMEDOUT;
scoped_guard(spinlock_irqsave, &ctx->rx_lock) {
if (ctx->rx_len != sizeof(*resp))
return -EIO;
memcpy(resp, ctx->rx_buf, sizeof(*resp));
}
return 0;
}
static const struct rtpse_mcu_transport_ops rtpse_mcu_uart_transport_ops = {
.send = rtpse_mcu_uart_send,
.recv = rtpse_mcu_uart_recv,
};
static int rtpse_mcu_uart_probe(struct serdev_device *serdev)
{
u32 speed = RTPSE_MCU_UART_BAUD_DEFAULT;
struct device *dev = &serdev->dev;
struct rtpse_mcu_uart *ctx;
unsigned int baud;
int ret;
ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
ctx->serdev = serdev;
ctx->pse.dev = dev;
ctx->pse.pcdev.owner = THIS_MODULE;
ctx->pse.transport = &rtpse_mcu_uart_transport_ops;
init_completion(&ctx->rx_done);
spin_lock_init(&ctx->rx_lock);
serdev_device_set_drvdata(serdev, ctx);
serdev_device_set_client_ops(serdev, &rtpse_mcu_uart_serdev_ops);
ret = devm_serdev_device_open(dev, serdev);
if (ret)
return dev_err_probe(dev, ret, "failed to open serdev\n");
fwnode_property_read_u32(dev_fwnode(dev), "current-speed", &speed);
baud = serdev_device_set_baudrate(serdev, speed);
if (baud != speed)
dev_warn(dev, "could not set baudrate %u, controller uses %u\n",
speed, baud);
serdev_device_set_flow_control(serdev, false);
ret = serdev_device_set_parity(serdev, SERDEV_PARITY_NONE);
if (ret)
dev_warn(dev, "could not set parity to none: %d\n", ret);
return rtpse_mcu_register(&ctx->pse);
}
static const struct of_device_id rtpse_mcu_uart_of_match[] = {
{ .compatible = "realtek,pse-mcu-gen1", .data = &rtpse_mcu_gen1_data },
{ .compatible = "realtek,pse-mcu-gen2", .data = &rtpse_mcu_gen2_data },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, rtpse_mcu_uart_of_match);
static struct serdev_device_driver rtpse_mcu_uart_driver = {
.driver = {
.name = "realtek-pse-mcu-uart",
.of_match_table = rtpse_mcu_uart_of_match,
},
.probe = rtpse_mcu_uart_probe,
};
module_serdev_device_driver(rtpse_mcu_uart_driver);
MODULE_AUTHOR("Jonas Jelonek <jelonek.jonas@gmail.com>");
MODULE_DESCRIPTION("Realtek PSE MCU driver (UART transport)");
MODULE_LICENSE("GPL");
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