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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-08-07 13:11:22 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-08-07 13:11:22 +0000 |
commit | b20732900e4636a467c0183a47f7396700f5f743 (patch) | |
tree | 42f079ff82e701ebcb76829974b4caca3e5b6798 /drivers/tty/serial/stm32-usart.c | |
parent | Adding upstream version 6.8.12. (diff) | |
download | linux-b20732900e4636a467c0183a47f7396700f5f743.tar.xz linux-b20732900e4636a467c0183a47f7396700f5f743.zip |
Adding upstream version 6.9.7.upstream/6.9.7
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/tty/serial/stm32-usart.c')
-rw-r--r-- | drivers/tty/serial/stm32-usart.c | 223 |
1 files changed, 136 insertions, 87 deletions
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index d103b07d10..4fa5a03eba 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -9,6 +9,7 @@ * Inspired by st-asc.c from STMicroelectronics (c) */ +#include <linux/bitfield.h> #include <linux/clk.h> #include <linux/console.h> #include <linux/delay.h> @@ -39,60 +40,64 @@ /* Register offsets */ static struct stm32_usart_info __maybe_unused stm32f4_info = { .ofs = { - .isr = 0x00, - .rdr = 0x04, - .tdr = 0x04, - .brr = 0x08, - .cr1 = 0x0c, - .cr2 = 0x10, - .cr3 = 0x14, - .gtpr = 0x18, - .rtor = UNDEF_REG, - .rqr = UNDEF_REG, - .icr = UNDEF_REG, + .isr = 0x00, + .rdr = 0x04, + .tdr = 0x04, + .brr = 0x08, + .cr1 = 0x0c, + .cr2 = 0x10, + .cr3 = 0x14, + .gtpr = 0x18, + .rtor = UNDEF_REG, + .rqr = UNDEF_REG, + .icr = UNDEF_REG, + .presc = UNDEF_REG, + .hwcfgr1 = UNDEF_REG, }, .cfg = { .uart_enable_bit = 13, .has_7bits_data = false, - .fifosize = 1, } }; static struct stm32_usart_info __maybe_unused stm32f7_info = { .ofs = { - .cr1 = 0x00, - .cr2 = 0x04, - .cr3 = 0x08, - .brr = 0x0c, - .gtpr = 0x10, - .rtor = 0x14, - .rqr = 0x18, - .isr = 0x1c, - .icr = 0x20, - .rdr = 0x24, - .tdr = 0x28, + .cr1 = 0x00, + .cr2 = 0x04, + .cr3 = 0x08, + .brr = 0x0c, + .gtpr = 0x10, + .rtor = 0x14, + .rqr = 0x18, + .isr = 0x1c, + .icr = 0x20, + .rdr = 0x24, + .tdr = 0x28, + .presc = UNDEF_REG, + .hwcfgr1 = UNDEF_REG, }, .cfg = { .uart_enable_bit = 0, .has_7bits_data = true, .has_swap = true, - .fifosize = 1, } }; static struct stm32_usart_info __maybe_unused stm32h7_info = { .ofs = { - .cr1 = 0x00, - .cr2 = 0x04, - .cr3 = 0x08, - .brr = 0x0c, - .gtpr = 0x10, - .rtor = 0x14, - .rqr = 0x18, - .isr = 0x1c, - .icr = 0x20, - .rdr = 0x24, - .tdr = 0x28, + .cr1 = 0x00, + .cr2 = 0x04, + .cr3 = 0x08, + .brr = 0x0c, + .gtpr = 0x10, + .rtor = 0x14, + .rqr = 0x18, + .isr = 0x1c, + .icr = 0x20, + .rdr = 0x24, + .tdr = 0x28, + .presc = 0x2c, + .hwcfgr1 = 0x3f0, }, .cfg = { .uart_enable_bit = 0, @@ -100,7 +105,6 @@ static struct stm32_usart_info __maybe_unused stm32h7_info = { .has_swap = true, .has_wakeup = true, .has_fifo = true, - .fifosize = 16, } }; @@ -1156,6 +1160,8 @@ static void stm32_usart_shutdown(struct uart_port *port) free_irq(port->irq, port); } +static const unsigned int stm32_usart_presc_val[] = {1, 2, 4, 6, 8, 10, 12, 16, 32, 64, 128, 256}; + static void stm32_usart_set_termios(struct uart_port *port, struct ktermios *termios, const struct ktermios *old) @@ -1164,17 +1170,19 @@ static void stm32_usart_set_termios(struct uart_port *port, const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; const struct stm32_usart_config *cfg = &stm32_port->info->cfg; struct serial_rs485 *rs485conf = &port->rs485; - unsigned int baud, bits; + unsigned int baud, bits, uart_clk, uart_clk_pres; u32 usartdiv, mantissa, fraction, oversampling; tcflag_t cflag = termios->c_cflag; - u32 cr1, cr2, cr3, isr; + u32 cr1, cr2, cr3, isr, brr, presc; unsigned long flags; int ret; if (!stm32_port->hw_flow_control) cflag &= ~CRTSCTS; - baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 8); + uart_clk = clk_get_rate(stm32_port->clk); + + baud = uart_get_baud_rate(port, termios, old, 0, uart_clk / 8); uart_port_lock_irqsave(port, &flags); @@ -1276,27 +1284,48 @@ static void stm32_usart_set_termios(struct uart_port *port, cr3 |= USART_CR3_CTSE | USART_CR3_RTSE; } - usartdiv = DIV_ROUND_CLOSEST(port->uartclk, baud); + for (presc = 0; presc <= USART_PRESC_MAX; presc++) { + uart_clk_pres = DIV_ROUND_CLOSEST(uart_clk, stm32_usart_presc_val[presc]); + usartdiv = DIV_ROUND_CLOSEST(uart_clk_pres, baud); - /* - * The USART supports 16 or 8 times oversampling. - * By default we prefer 16 times oversampling, so that the receiver - * has a better tolerance to clock deviations. - * 8 times oversampling is only used to achieve higher speeds. - */ - if (usartdiv < 16) { - oversampling = 8; - cr1 |= USART_CR1_OVER8; - stm32_usart_set_bits(port, ofs->cr1, USART_CR1_OVER8); - } else { - oversampling = 16; - cr1 &= ~USART_CR1_OVER8; - stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_OVER8); + /* + * The USART supports 16 or 8 times oversampling. + * By default we prefer 16 times oversampling, so that the receiver + * has a better tolerance to clock deviations. + * 8 times oversampling is only used to achieve higher speeds. + */ + if (usartdiv < 16) { + oversampling = 8; + cr1 |= USART_CR1_OVER8; + stm32_usart_set_bits(port, ofs->cr1, USART_CR1_OVER8); + } else { + oversampling = 16; + cr1 &= ~USART_CR1_OVER8; + stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_OVER8); + } + + mantissa = (usartdiv / oversampling) << USART_BRR_DIV_M_SHIFT; + fraction = usartdiv % oversampling; + brr = mantissa | fraction; + + if (FIELD_FIT(USART_BRR_MASK, brr)) { + if (ofs->presc != UNDEF_REG) { + port->uartclk = uart_clk_pres; + writel_relaxed(presc, port->membase + ofs->presc); + } else if (presc) { + /* We need a prescaler but we don't have it (STM32F4, STM32F7) */ + dev_err(port->dev, + "unable to set baudrate, input clock is too high"); + } + break; + } else if (presc == USART_PRESC_MAX) { + /* Even with prescaler and brr at max value we can't set baudrate */ + dev_err(port->dev, "unable to set baudrate, input clock is too high"); + break; + } } - mantissa = (usartdiv / oversampling) << USART_BRR_DIV_M_SHIFT; - fraction = usartdiv % oversampling; - writel_relaxed(mantissa | fraction, port->membase + ofs->brr); + writel_relaxed(brr, port->membase + ofs->brr); uart_update_timeout(port, cflag, baud); @@ -1480,37 +1509,57 @@ static const struct uart_ops stm32_uart_ops = { #endif /* CONFIG_CONSOLE_POLL */ }; -/* - * STM32H7 RX & TX FIFO threshold configuration (CR3 RXFTCFG / TXFTCFG) - * Note: 1 isn't a valid value in RXFTCFG / TXFTCFG. In this case, - * RXNEIE / TXEIE can be used instead of threshold irqs: RXFTIE / TXFTIE. - * So, RXFTCFG / TXFTCFG bitfields values are encoded as array index + 1. - */ -static const u32 stm32h7_usart_fifo_thresh_cfg[] = { 1, 2, 4, 8, 12, 14, 16 }; +struct stm32_usart_thresh_ratio { + int mul; + int div; +}; + +static const struct stm32_usart_thresh_ratio stm32h7_usart_fifo_thresh_cfg[] = { + {1, 8}, {1, 4}, {1, 2}, {3, 4}, {7, 8}, {1, 1} }; + +static int stm32_usart_get_thresh_value(u32 fifo_size, int index) +{ + return fifo_size * stm32h7_usart_fifo_thresh_cfg[index].mul / + stm32h7_usart_fifo_thresh_cfg[index].div; +} -static void stm32_usart_get_ftcfg(struct platform_device *pdev, const char *p, - int *ftcfg) +static int stm32_usart_get_ftcfg(struct platform_device *pdev, struct stm32_port *stm32port, + const char *p, int *ftcfg) { - u32 bytes, i; + const struct stm32_usart_offsets *ofs = &stm32port->info->ofs; + u32 bytes, i, cfg8; + int fifo_size; + + if (WARN_ON(ofs->hwcfgr1 == UNDEF_REG)) + return 1; + + cfg8 = FIELD_GET(USART_HWCFGR1_CFG8, + readl_relaxed(stm32port->port.membase + ofs->hwcfgr1)); + + /* On STM32H7, hwcfgr is not present, so returned value will be 0 */ + fifo_size = cfg8 ? 1 << cfg8 : STM32H7_USART_FIFO_SIZE; - /* DT option to get RX & TX FIFO threshold (default to 8 bytes) */ + /* DT option to get RX & TX FIFO threshold (default to half fifo size) */ if (of_property_read_u32(pdev->dev.of_node, p, &bytes)) - bytes = 8; + bytes = fifo_size / 2; - for (i = 0; i < ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg); i++) - if (stm32h7_usart_fifo_thresh_cfg[i] >= bytes) + if (bytes < stm32_usart_get_thresh_value(fifo_size, 0)) { + *ftcfg = -EINVAL; + return fifo_size; + } + + for (i = 0; i < ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg); i++) { + if (stm32_usart_get_thresh_value(fifo_size, i) >= bytes) break; + } if (i >= ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg)) i = ARRAY_SIZE(stm32h7_usart_fifo_thresh_cfg) - 1; - dev_dbg(&pdev->dev, "%s set to %d bytes\n", p, - stm32h7_usart_fifo_thresh_cfg[i]); + dev_dbg(&pdev->dev, "%s set to %d/%d bytes\n", p, + stm32_usart_get_thresh_value(fifo_size, i), fifo_size); - /* Provide FIFO threshold ftcfg (1 is invalid: threshold irq unused) */ - if (i) - *ftcfg = i - 1; - else - *ftcfg = -EINVAL; + *ftcfg = i; + return fifo_size; } static void stm32_usart_deinit_port(struct stm32_port *stm32port) @@ -1540,7 +1589,6 @@ static int stm32_usart_init_port(struct stm32_port *stm32port, port->flags = UPF_BOOT_AUTOCONF; port->ops = &stm32_uart_ops; port->dev = &pdev->dev; - port->fifosize = stm32port->info->cfg.fifosize; port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_STM32_CONSOLE); port->irq = irq; port->rs485_config = stm32_usart_config_rs485; @@ -1556,14 +1604,6 @@ static int stm32_usart_init_port(struct stm32_port *stm32port, stm32port->swap = stm32port->info->cfg.has_swap && of_property_read_bool(pdev->dev.of_node, "rx-tx-swap"); - stm32port->fifoen = stm32port->info->cfg.has_fifo; - if (stm32port->fifoen) { - stm32_usart_get_ftcfg(pdev, "rx-threshold", - &stm32port->rxftcfg); - stm32_usart_get_ftcfg(pdev, "tx-threshold", - &stm32port->txftcfg); - } - port->membase = devm_platform_get_and_ioremap_resource(pdev, 0, &res); if (IS_ERR(port->membase)) return PTR_ERR(port->membase); @@ -1586,6 +1626,15 @@ static int stm32_usart_init_port(struct stm32_port *stm32port, goto err_clk; } + stm32port->fifoen = stm32port->info->cfg.has_fifo; + if (stm32port->fifoen) { + stm32_usart_get_ftcfg(pdev, stm32port, "rx-threshold", &stm32port->rxftcfg); + port->fifosize = stm32_usart_get_ftcfg(pdev, stm32port, "tx-threshold", + &stm32port->txftcfg); + } else { + port->fifosize = 1; + } + stm32port->gpios = mctrl_gpio_init(&stm32port->port, 0); if (IS_ERR(stm32port->gpios)) { ret = PTR_ERR(stm32port->gpios); |