Re: [PATCH 4/4] drivers/tty/serial: add ESP32S3 ACM device driver

[Max Filippov]

On Thu, Sep 14, 2023 at 12:16 AM Jiri Slaby <jirislaby@xxxxxxxxxx> wrote:
>
> On 13. 09. 23, 23:14, Max Filippov wrote:
> > Add driver for the ACM  controller of the Espressif ESP32S3 Soc.
> > Hardware specification is available at the following URL:
> >
> >    https://www.espressif.com/sites/default/files/documentation/esp32-s3_technical_reference_manual_en.pdf
> >    (Chapter 33 USB Serial/JTAG Controller)
> ...
>
> > +static void esp32s3_acm_put_char_sync(struct uart_port *port, unsigned char c)
> > +{
> > +     while (!esp32s3_acm_tx_fifo_free(port))
> > +             cpu_relax();
>
> No limits...

Fixed.

> > +     esp32s3_acm_put_char(port, c);
> > +     esp32s3_acm_push(port);
> > +}
> > +
> > +static void esp32s3_acm_transmit_buffer(struct uart_port *port)
> > +{
>
> tx helper.

Ok.

> > +     struct circ_buf *xmit = &port->state->xmit;
> > +     u32 tx_fifo_used = esp32s3_acm_tx_fifo_cnt(port);
> > +
> > +     if (esp32s3_acm_tx_fifo_free(port)) {
> > +             while (!uart_circ_empty(xmit) && tx_fifo_used < ESP32S3_ACM_TX_FIFO_SIZE) {
> > +                     esp32s3_acm_put_char(port, xmit->buf[xmit->tail]);
> > +                     xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
> > +                     port->icount.tx++;
> > +                     ++tx_fifo_used;
> > +             }
> > +     }
> > +
> > +     if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
> > +             uart_write_wakeup(port);
> > +
> > +     if (uart_circ_empty(xmit)) {
> > +             esp32s3_acm_stop_tx(port);
> > +     } else {
> > +             u32 int_ena;
> > +
> > +             int_ena = esp32s3_acm_read(port, USB_SERIAL_JTAG_INT_ENA_REG);
> > +             esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG,
> > +                               int_ena | USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ENA_MASK);
> > +     }
> > +
> > +     if (tx_fifo_used > 0 && tx_fifo_used < ESP32S3_ACM_TX_FIFO_SIZE)
> > +             esp32s3_acm_write(port, USB_SERIAL_JTAG_EP1_CONF_REG,
> > +                               USB_SERIAL_JTAG_WR_DONE_MASK);
> > +}
>
>
> > +static irqreturn_t esp32s3_acm_int(int irq, void *dev_id)
> > +{
> > +     struct uart_port *port = dev_id;
> > +     u32 status;
> > +
> > +     status = esp32s3_acm_read(port, USB_SERIAL_JTAG_INT_ST_REG);
> > +     esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_CLR_REG, status);
> > +
> > +     if (status & USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ST_MASK)
> > +             esp32s3_acm_rxint(port);
> > +     if (status & USB_SERIAL_JTAG_SERIAL_IN_EMPTY_INT_ST_MASK)
> > +             esp32s3_acm_txint(port);
> > +
> > +     return IRQ_HANDLED;
>
> IRQ_STATUS()

Ok.

> > +}
>
> > +static int esp32s3_acm_startup(struct uart_port *port)
> > +{
> > +     int ret = 0;
> > +
> > +     esp32s3_acm_write(port, USB_SERIAL_JTAG_INT_ENA_REG,
> > +                       USB_SERIAL_JTAG_SERIAL_OUT_RECV_PKT_INT_ENA_MASK);
> > +     ret = devm_request_irq(port->dev, port->irq, esp32s3_acm_int, 0,
> > +                            DRIVER_NAME, port);
> > +     return ret;
>
> No need for ret. Or not, you don't handle the failure properly again
> (disable ints). And the order appears to be switched too.

Fixed.

> > +static void
> > +esp32s3_acm_console_write(struct console *co, const char *s, unsigned int count)
> > +{
> > +     struct uart_port *port = esp32s3_acm_ports[co->index];
> > +     unsigned long flags;
> > +     int locked = 1;
>
> bool? ANd in the otrher driver too.

Ok.

> > +
> > +     if (port->sysrq)
> > +             locked = 0;
> > +     else if (oops_in_progress)
> > +             locked = spin_trylock_irqsave(&port->lock, flags);
> > +     else
> > +             spin_lock_irqsave(&port->lock, flags);
> > +
> > +     esp32s3_acm_string_write(port, s, count);
> > +
> > +     if (locked)
> > +             spin_unlock_irqrestore(&port->lock, flags);
> > +}
>
>
> > +#ifdef CONFIG_CONSOLE_POLL
> > +static int esp32s3_acm_earlycon_read(struct console *con, char *s, unsigned int n)
> > +{
> > +     struct earlycon_device *dev = con->data;
> > +     int num_read = 0;
>
> num looks like should be unsigned?

Ok.

> > +
> > +     while (num_read < n) {
> > +             int c = esp32s3_acm_poll_get_char(&dev->port);
> > +
> > +             if (c == NO_POLL_CHAR)
> > +                     break;
> > +             s[num_read++] = c;
> > +     }
> > +     return num_read;
> > +}
> > +#endif
>
>
> > +static int esp32s3_acm_probe(struct platform_device *pdev)
> > +{
> > +     struct device_node *np = pdev->dev.of_node;
> > +     struct uart_port *port;
> > +     struct resource *res;
> > +     int ret;
> > +
> > +     port = devm_kzalloc(&pdev->dev, sizeof(*port), GFP_KERNEL);
> > +     if (!port)
> > +             return -ENOMEM;
> > +
> > +     ret = of_alias_get_id(np, "serial");
> > +     if (ret < 0) {
> > +             dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);
> > +             return ret;
> > +     }
> > +     if (ret >= UART_NR) {
> > +             dev_err(&pdev->dev, "driver limited to %d serial ports\n",
> > +                     UART_NR);
> > +             return -ENOMEM;
> > +     }
> > +
> > +     port->line = ret;
> > +
> > +     res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > +     if (!res)
> > +             return -ENODEV;
> > +
> > +     port->mapbase = res->start;
> > +     port->membase = devm_ioremap_resource(&pdev->dev, res);
> > +     if (IS_ERR(port->membase))
> > +             return PTR_ERR(port->membase);
> > +
> > +     port->dev = &pdev->dev;
> > +     port->type = PORT_ESP32ACM;
> > +     port->iotype = UPIO_MEM;
> > +     port->irq = platform_get_irq(pdev, 0);
> > +     port->ops = &esp32s3_acm_pops;
> > +     port->flags = UPF_BOOT_AUTOCONF;
> > +     port->has_sysrq = 1;
> > +     port->fifosize = ESP32S3_ACM_TX_FIFO_SIZE;
> > +
> > +     esp32s3_acm_ports[port->line] = port;
> > +
> > +     platform_set_drvdata(pdev, port);
> > +
> > +     ret = uart_add_one_port(&esp32s3_acm_reg, port);
> > +     return ret;
>
> return imm.

Ok.

-- 
Thanks.
-- Max