| Message ID | 20230920022644.2712651-1-jcmvbkbc@gmail.com |
|---|---|
| Headers | show |
| Series | serial: add drivers for the ESP32xx serial devices | expand |
On 20. 09. 23, 4:26, Max Filippov wrote: > Add driver for the UART controllers of the Espressif ESP32 and ESP32S3 > SoCs. Hardware specification is available at the following URLs: ... > +static void esp32_uart_rxint(struct uart_port *port) > +{ > + struct tty_port *tty_port = &port->state->port; > + u32 rx_fifo_cnt = esp32_uart_rx_fifo_cnt(port); > + unsigned long flags; > + u32 i; > + > + if (!rx_fifo_cnt) > + return; > + > + spin_lock_irqsave(&port->lock, flags); > + > + for (i = 0; i < rx_fifo_cnt; ++i) { > + u32 rx = esp32_uart_read(port, UART_FIFO_REG); > + u32 brk = 0; > + > + ++port->icount.rx; Should yuou increment this only in case of insert_flip_char()? > + if (!rx) { > + brk = esp32_uart_read(port, UART_INT_ST_REG) & > + UART_BRK_DET_INT; > + } > + if (brk) { > + esp32_uart_write(port, UART_INT_CLR_REG, brk); > + ++port->icount.brk; > + uart_handle_break(port); > + } else { > + if (uart_handle_sysrq_char(port, (unsigned char)rx)) > + continue; > + tty_insert_flip_char(tty_port, rx, TTY_NORMAL); > + } This is heavy. Is it equivalent to: if (!rx && esp32_uart_read(port, UART_INT_ST_REG) & UART_BRK_DET_INT) { esp32_uart_write(port, UART_INT_CLR_REG, brk); ++port->icount.brk; uart_handle_break(port); continue; } if (uart_handle_sysrq_char(port, (unsigned char)rx)) continue; tty_insert_flip_char(tty_port, rx, TTY_NORMAL); ? > + } > + spin_unlock_irqrestore(&port->lock, flags); > + > + tty_flip_buffer_push(tty_port); > +} ... > +static void esp32_uart_put_char_sync(struct uart_port *port, u8 c) > +{ > + unsigned long timeout; > + > + timeout = jiffies + msecs_to_jiffies(1000); I.e. plus HZ? > + while (esp32_uart_tx_fifo_cnt(port) >= ESP32_UART_TX_FIFO_SIZE) { > + if (time_after(jiffies, timeout)) { > + dev_warn(port->dev, "timeout waiting for TX FIFO\n"); > + return; > + } > + cpu_relax(); > + } > + esp32_uart_put_char(port, c); > +} > + > +static void esp32_uart_transmit_buffer(struct uart_port *port) > +{ > + u32 tx_fifo_used = esp32_uart_tx_fifo_cnt(port); > + > + if (tx_fifo_used < ESP32_UART_TX_FIFO_SIZE) { Invert the condition and return here? > + unsigned int pending; > + u8 ch; > + > + pending = uart_port_tx_limited(port, ch, > + ESP32_UART_TX_FIFO_SIZE - tx_fifo_used, > + true, esp32_uart_put_char(port, ch), > + ({})); > + if (pending) { > + u32 int_ena; > + > + int_ena = esp32_uart_read(port, UART_INT_ENA_REG); > + int_ena |= UART_TXFIFO_EMPTY_INT; > + esp32_uart_write(port, UART_INT_ENA_REG, int_ena); > + } > + } > +} > +static irqreturn_t esp32_uart_int(int irq, void *dev_id) > +{ > + struct uart_port *port = dev_id; > + u32 status; > + > + status = esp32_uart_read(port, UART_INT_ST_REG); > + > + if (status & (UART_RXFIFO_FULL_INT | UART_BRK_DET_INT)) > + esp32_uart_rxint(port); > + if (status & UART_TXFIFO_EMPTY_INT) > + esp32_uart_txint(port); > + > + esp32_uart_write(port, UART_INT_CLR_REG, status); \n here please. > + return IRQ_RETVAL(status); > +} > +static int esp32_uart_startup(struct uart_port *port) > +{ > + int ret = 0; > + unsigned long flags; > + struct esp32_port *sport = container_of(port, struct esp32_port, port); > + > + ret = clk_prepare_enable(sport->clk); > + if (ret) > + return ret; > + > + ret = devm_request_irq(port->dev, port->irq, esp32_uart_int, 0, > + DRIVER_NAME, port); > + if (ret) { > + clk_disable_unprepare(sport->clk); > + return ret; > + } > + > + spin_lock_irqsave(&port->lock, flags); > + esp32_uart_write(port, UART_CONF1_REG, > + (1 << UART_RXFIFO_FULL_THRHD_SHIFT) | BIT() ? > + (1 << port_variant(port)->txfifo_empty_thrhd_shift)); And here? > + esp32_uart_write(port, UART_INT_CLR_REG, UART_RXFIFO_FULL_INT | UART_BRK_DET_INT); > + esp32_uart_write(port, UART_INT_ENA_REG, UART_RXFIFO_FULL_INT | UART_BRK_DET_INT); > + spin_unlock_irqrestore(&port->lock, flags); > + > + pr_debug("%s, conf1 = %08x, int_st = %08x, status = %08x\n", > + __func__, > + esp32_uart_read(port, UART_CONF1_REG), > + esp32_uart_read(port, UART_INT_ST_REG), > + esp32_uart_read(port, UART_STATUS_REG)); \n here. Is this debug printout somehow useful? > + return ret; > +} > + > +static void esp32_uart_shutdown(struct uart_port *port) > +{ > + struct esp32_port *sport = container_of(port, struct esp32_port, port); > + > + esp32_uart_write(port, UART_INT_ENA_REG, 0); > + devm_free_irq(port->dev, port->irq, port); I wonder why to use devm_ after all? > + clk_disable_unprepare(sport->clk); > +} > + > +static bool esp32_uart_set_baud(struct uart_port *port, u32 baud) > +{ > + u32 div = port->uartclk / baud; > + u32 frag = (port->uartclk * 16) / baud - div * 16; > + > + if (div <= port_variant(port)->clkdiv_mask) { > + esp32_uart_write(port, UART_CLKDIV_REG, > + div | FIELD_PREP(UART_CLKDIV_FRAG, frag)); > + return true; > + } \n > + return false; > +} ... > +static int __init esp32s3_uart_early_console_setup(struct earlycon_device *device, > + const char *options) > +{ > + device->port.private_data = (void *)&esp32s3_variant; No need to cast, right? \n > + return esp32xx_uart_early_console_setup(device, options); > +} ... > +static int esp32_uart_probe(struct platform_device *pdev) > +{ > + struct device_node *np = pdev->dev.of_node; > + static const struct of_device_id *match; > + struct uart_port *port; > + struct esp32_port *sport; > + struct resource *res; > + int ret; > + > + match = of_match_device(esp32_uart_dt_ids, &pdev->dev); > + if (!match) > + return -ENODEV; > + > + sport = devm_kzalloc(&pdev->dev, sizeof(*sport), GFP_KERNEL); > + if (!sport) > + return -ENOMEM; > + > + port = &sport->port; > + > + 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); > + > + sport->clk = devm_clk_get(&pdev->dev, NULL); > + if (IS_ERR(sport->clk)) > + return PTR_ERR(sport->clk); > + > + port->uartclk = clk_get_rate(sport->clk); > + port->dev = &pdev->dev; > + port->type = PORT_ESP32UART; > + port->iotype = UPIO_MEM; > + port->irq = platform_get_irq(pdev, 0); > + port->ops = &esp32_uart_pops; > + port->flags = UPF_BOOT_AUTOCONF; > + port->has_sysrq = 1; > + port->fifosize = ESP32_UART_TX_FIFO_SIZE; > + port->private_data = (void *)match->data; No need to cast. > + > + esp32_uart_ports[port->line] = sport; > + > + platform_set_drvdata(pdev, port); > + > + return uart_add_one_port(&esp32_uart_reg, port); > +} regards,
On Wed, Sep 20, 2023 at 12:22 AM Jiri Slaby <jirislaby@kernel.org> wrote: > > On 20. 09. 23, 4:26, Max Filippov wrote: > > Add driver for the UART controllers of the Espressif ESP32 and ESP32S3 > > SoCs. Hardware specification is available at the following URLs: > ... > > +static void esp32_uart_rxint(struct uart_port *port) > > +{ > > + struct tty_port *tty_port = &port->state->port; > > + u32 rx_fifo_cnt = esp32_uart_rx_fifo_cnt(port); > > + unsigned long flags; > > + u32 i; > > + > > + if (!rx_fifo_cnt) > > + return; > > + > > + spin_lock_irqsave(&port->lock, flags); > > + > > + for (i = 0; i < rx_fifo_cnt; ++i) { > > + u32 rx = esp32_uart_read(port, UART_FIFO_REG); > > + u32 brk = 0; > > + > > + ++port->icount.rx; > > Should yuou increment this only in case of insert_flip_char()? I don't know. Does port->icount.rx have clearly defined semantics? I've looked through multiple other serial drivers and there's a lot of examples of similar pattern. > > + if (!rx) { > > + brk = esp32_uart_read(port, UART_INT_ST_REG) & > > + UART_BRK_DET_INT; > > + } > > + if (brk) { > > + esp32_uart_write(port, UART_INT_CLR_REG, brk); > > + ++port->icount.brk; > > + uart_handle_break(port); > > + } else { > > + if (uart_handle_sysrq_char(port, (unsigned char)rx)) > > + continue; > > + tty_insert_flip_char(tty_port, rx, TTY_NORMAL); > > + } > > This is heavy. Is it equivalent to: > if (!rx && esp32_uart_read(port, UART_INT_ST_REG) & > UART_BRK_DET_INT) { > esp32_uart_write(port, UART_INT_CLR_REG, brk); > ++port->icount.brk; > uart_handle_break(port); > continue; > } > > if (uart_handle_sysrq_char(port, (unsigned char)rx)) > continue; > > tty_insert_flip_char(tty_port, rx, TTY_NORMAL); > > ? It is equivalent, but I find the version that I used somewhat easier to read. Maybe this: if (!rx && (esp32_uart_read(port, UART_INT_ST_REG) & UART_BRK_DET_INT)) { esp32_uart_write(port, UART_INT_CLR_REG, brk); ++port->icount.brk; uart_handle_break(port); } else { if (uart_handle_sysrq_char(port, (unsigned char)rx)) continue; tty_insert_flip_char(tty_port, rx, TTY_NORMAL); } ? > > + } > > + spin_unlock_irqrestore(&port->lock, flags); > > + > > + tty_flip_buffer_push(tty_port); > > +} > ... > > +static void esp32_uart_put_char_sync(struct uart_port *port, u8 c) > > +{ > > + unsigned long timeout; > > + > > + timeout = jiffies + msecs_to_jiffies(1000); > > I.e. plus HZ? Yes, ok. > > + while (esp32_uart_tx_fifo_cnt(port) >= ESP32_UART_TX_FIFO_SIZE) { > > + if (time_after(jiffies, timeout)) { > > + dev_warn(port->dev, "timeout waiting for TX FIFO\n"); > > + return; > > + } > > + cpu_relax(); > > + } > > + esp32_uart_put_char(port, c); > > +} > > + > > +static void esp32_uart_transmit_buffer(struct uart_port *port) > > +{ > > + u32 tx_fifo_used = esp32_uart_tx_fifo_cnt(port); > > + > > + if (tx_fifo_used < ESP32_UART_TX_FIFO_SIZE) { > > Invert the condition and return here? Ok. > > + unsigned int pending; > > + u8 ch; > > + > > + pending = uart_port_tx_limited(port, ch, > > + ESP32_UART_TX_FIFO_SIZE - tx_fifo_used, > > + true, esp32_uart_put_char(port, ch), > > + ({})); > > + if (pending) { > > + u32 int_ena; > > + > > + int_ena = esp32_uart_read(port, UART_INT_ENA_REG); > > + int_ena |= UART_TXFIFO_EMPTY_INT; > > + esp32_uart_write(port, UART_INT_ENA_REG, int_ena); > > + } > > + } > > +} > > > > +static irqreturn_t esp32_uart_int(int irq, void *dev_id) > > +{ > > + struct uart_port *port = dev_id; > > + u32 status; > > + > > + status = esp32_uart_read(port, UART_INT_ST_REG); > > + > > + if (status & (UART_RXFIFO_FULL_INT | UART_BRK_DET_INT)) > > + esp32_uart_rxint(port); > > + if (status & UART_TXFIFO_EMPTY_INT) > > + esp32_uart_txint(port); > > + > > + esp32_uart_write(port, UART_INT_CLR_REG, status); > > \n here please. Ok > > + return IRQ_RETVAL(status); > > +} > > > +static int esp32_uart_startup(struct uart_port *port) > > +{ > > + int ret = 0; > > + unsigned long flags; > > + struct esp32_port *sport = container_of(port, struct esp32_port, port); > > + > > + ret = clk_prepare_enable(sport->clk); > > + if (ret) > > + return ret; > > + > > + ret = devm_request_irq(port->dev, port->irq, esp32_uart_int, 0, > > + DRIVER_NAME, port); > > + if (ret) { > > + clk_disable_unprepare(sport->clk); > > + return ret; > > + } > > + > > + spin_lock_irqsave(&port->lock, flags); > > + esp32_uart_write(port, UART_CONF1_REG, > > + (1 << UART_RXFIFO_FULL_THRHD_SHIFT) | > > BIT() ? > > > + (1 << port_variant(port)->txfifo_empty_thrhd_shift)); > > And here? These are not logically bits, in both cases I put value 1 into multiple-bit fields. > > + esp32_uart_write(port, UART_INT_CLR_REG, UART_RXFIFO_FULL_INT | UART_BRK_DET_INT); > > + esp32_uart_write(port, UART_INT_ENA_REG, UART_RXFIFO_FULL_INT | UART_BRK_DET_INT); > > + spin_unlock_irqrestore(&port->lock, flags); > > + > > + pr_debug("%s, conf1 = %08x, int_st = %08x, status = %08x\n", > > + __func__, > > + esp32_uart_read(port, UART_CONF1_REG), > > + esp32_uart_read(port, UART_INT_ST_REG), > > + esp32_uart_read(port, UART_STATUS_REG)); > > \n here. Is this debug printout somehow useful? I'll drop it. > > + return ret; > > +} > > + > > +static void esp32_uart_shutdown(struct uart_port *port) > > +{ > > + struct esp32_port *sport = container_of(port, struct esp32_port, port); > > + > > + esp32_uart_write(port, UART_INT_ENA_REG, 0); > > + devm_free_irq(port->dev, port->irq, port); > > I wonder why to use devm_ after all? I'll switch to non-devm_ version. > > + clk_disable_unprepare(sport->clk); > > +} > > + > > +static bool esp32_uart_set_baud(struct uart_port *port, u32 baud) > > +{ > > + u32 div = port->uartclk / baud; > > + u32 frag = (port->uartclk * 16) / baud - div * 16; > > + > > + if (div <= port_variant(port)->clkdiv_mask) { > > + esp32_uart_write(port, UART_CLKDIV_REG, > > + div | FIELD_PREP(UART_CLKDIV_FRAG, frag)); > > + return true; > > + } > > \n Ok. > > + return false; > > +} > ... > > +static int __init esp32s3_uart_early_console_setup(struct earlycon_device *device, > > + const char *options) > > +{ > > + device->port.private_data = (void *)&esp32s3_variant; > > No need to cast, right? private_data is void *, esp32s3_variant is a constant. > \n Ok. > > + return esp32xx_uart_early_console_setup(device, options); > > +} > ... > > +static int esp32_uart_probe(struct platform_device *pdev) > > +{ > > + struct device_node *np = pdev->dev.of_node; > > + static const struct of_device_id *match; > > + struct uart_port *port; > > + struct esp32_port *sport; > > + struct resource *res; > > + int ret; > > + > > + match = of_match_device(esp32_uart_dt_ids, &pdev->dev); > > + if (!match) > > + return -ENODEV; > > + > > + sport = devm_kzalloc(&pdev->dev, sizeof(*sport), GFP_KERNEL); > > + if (!sport) > > + return -ENOMEM; > > + > > + port = &sport->port; > > + > > + 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); > > + > > + sport->clk = devm_clk_get(&pdev->dev, NULL); > > + if (IS_ERR(sport->clk)) > > + return PTR_ERR(sport->clk); > > + > > + port->uartclk = clk_get_rate(sport->clk); > > + port->dev = &pdev->dev; > > + port->type = PORT_ESP32UART; > > + port->iotype = UPIO_MEM; > > + port->irq = platform_get_irq(pdev, 0); > > + port->ops = &esp32_uart_pops; > > + port->flags = UPF_BOOT_AUTOCONF; > > + port->has_sysrq = 1; > > + port->fifosize = ESP32_UART_TX_FIFO_SIZE; > > + port->private_data = (void *)match->data; > > No need to cast. This is again a const cast. > > + > > + esp32_uart_ports[port->line] = sport; > > + > > + platform_set_drvdata(pdev, port); > > + > > + return uart_add_one_port(&esp32_uart_reg, port); > > +} > > regards, > -- > js > suse labs >
On Tue, Sep 19, 2023 at 07:26:40PM -0700, Max Filippov wrote: > uart_get_baud_rate has input parameters 'min' and 'max' limiting the > range of acceptable baud rates from the caller's perspective. If neither > current or old termios structures have acceptable baud rate setting and > 9600 is not in the min/max range either the function returns 0 and > issues a warning. > However for a UART that does not support speed of 9600 baud this is > expected behavior. > Clarify that 0 can be (and always could be) returned from the > uart_get_baud_rate. Don't issue a warning in that case. > Move the warinng to the uart_get_divisor instead, which is often called > with the uart_get_baud_rate return value. > > Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> > --- > drivers/tty/serial/serial_core.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c > index 7bdc21d5e13b..a8e2915832e8 100644 > --- a/drivers/tty/serial/serial_core.c > +++ b/drivers/tty/serial/serial_core.c > @@ -431,7 +431,7 @@ EXPORT_SYMBOL(uart_update_timeout); > * baud. > * > * If the new baud rate is invalid, try the @old termios setting. If it's still > - * invalid, we try 9600 baud. > + * invalid, we try 9600 baud. If that is also invalid 0 is returned. > * > * The @termios structure is updated to reflect the baud rate we're actually > * going to be using. Don't do this for the case where B0 is requested ("hang > @@ -515,8 +515,6 @@ uart_get_baud_rate(struct uart_port *port, struct ktermios *termios, > max - 1, max - 1); > } > } > - /* Should never happen */ > - WARN_ON(1); I'm ok with this removal, but: > return 0; > } > EXPORT_SYMBOL(uart_get_baud_rate); > @@ -539,6 +537,7 @@ uart_get_divisor(struct uart_port *port, unsigned int baud) > { > unsigned int quot; > > + WARN_ON(baud == 0); Why is this needed? If this isn't happening today, then there's no need to check for this here. Or if it can happen, we should return an error, not cause a possible reboot of the system if panic-on-warn is enabled. thanks, greg k-h
On Thu, Sep 28, 2023 at 1:17 AM Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > On Tue, Sep 19, 2023 at 07:26:40PM -0700, Max Filippov wrote: > > @@ -539,6 +537,7 @@ uart_get_divisor(struct uart_port *port, unsigned int baud) > > { > > unsigned int quot; > > > > + WARN_ON(baud == 0); > > Why is this needed? If this isn't happening today, then there's no need > to check for this here. I'll drop it then.