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Diffstat (limited to 'drivers/serial/serial_stm32.c')
-rw-r--r--drivers/serial/serial_stm32.c246
1 files changed, 246 insertions, 0 deletions
diff --git a/drivers/serial/serial_stm32.c b/drivers/serial/serial_stm32.c
new file mode 100644
index 0000000000..a84e64e974
--- /dev/null
+++ b/drivers/serial/serial_stm32.c
@@ -0,0 +1,246 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2016, STMicroelectronics - All Rights Reserved
+ * Author(s): Vikas Manocha, <vikas.manocha@st.com> for STMicroelectronics.
+ */
+
+#include <common.h>
+#include <console.h>
+#include <io.h>
+#include <linux/clk.h>
+#include <init.h>
+#include <driver.h>
+#include "serial_stm32.h"
+
+struct stm32_uart_info {
+ u8 uart_enable_bit; /* UART_CR1_UE */
+ bool stm32f4; /* true for STM32F4, false otherwise */
+ bool has_fifo;
+};
+
+struct stm32_uart {
+ struct console_device cdev;
+ void __iomem *base;
+ struct clk *clk;
+ bool stm32f4;
+ bool has_fifo;
+ int uart_enable_bit;
+};
+
+static struct stm32_uart *to_stm32_uart(struct console_device *cdev)
+{
+ return container_of(cdev, struct stm32_uart, cdev);
+}
+
+static int stm32_serial_setbaudrate(struct console_device *cdev, int baudrate)
+{
+ struct stm32_uart *stm32 = to_stm32_uart(cdev);
+ void __iomem *base = stm32->base;
+ bool stm32f4 = stm32->stm32f4;
+ u32 int_div, mantissa, fraction, oversampling;
+ unsigned long clock_rate;
+
+ clock_rate = clk_get_rate(stm32->clk);
+
+ int_div = DIV_ROUND_CLOSEST(clock_rate, baudrate);
+
+ if (int_div < 16) {
+ oversampling = 8;
+ setbits_le32(base + CR1_OFFSET(stm32f4), USART_CR1_OVER8);
+ } else {
+ oversampling = 16;
+ clrbits_le32(base + CR1_OFFSET(stm32f4), USART_CR1_OVER8);
+ }
+
+ mantissa = (int_div / oversampling) << USART_BRR_M_SHIFT;
+ fraction = int_div % oversampling;
+
+ writel(mantissa | fraction, base + BRR_OFFSET(stm32f4));
+
+ return 0;
+}
+
+static int stm32_serial_getc(struct console_device *cdev)
+{
+ struct stm32_uart *stm32 = to_stm32_uart(cdev);
+ void __iomem *base = stm32->base;
+ bool stm32f4 = stm32->stm32f4;
+ u32 isr = readl(base + ISR_OFFSET(stm32f4));
+
+ if ((isr & USART_ISR_RXNE) == 0)
+ return -EAGAIN;
+
+ if (isr & (USART_ISR_PE | USART_ISR_ORE)) {
+ if (!stm32f4)
+ setbits_le32(base + ICR_OFFSET,
+ USART_ICR_PCECF | USART_ICR_ORECF);
+ else
+ readl(base + RDR_OFFSET(stm32f4));
+ return -EIO;
+ }
+
+ return readl(base + RDR_OFFSET(stm32f4));
+}
+
+static void stm32_serial_putc(struct console_device *cdev, char c)
+{
+ struct stm32_uart *stm32 = to_stm32_uart(cdev);
+ void __iomem *base = stm32->base;
+ bool stm32f4 = stm32->stm32f4;
+
+ while ((readl(base + ISR_OFFSET(stm32f4)) & USART_ISR_TXE) == 0);
+
+ writel(c, base + TDR_OFFSET(stm32f4));
+}
+
+static int stm32_serial_tstc(struct console_device *cdev)
+{
+ struct stm32_uart *stm32 = to_stm32_uart(cdev);
+ void __iomem *base = stm32->base;
+ bool stm32f4 = stm32->stm32f4;
+
+ return readl(base + ISR_OFFSET(stm32f4)) & USART_ISR_RXNE ? 1 : 0;
+}
+
+static void stm32_serial_flush(struct console_device *cdev)
+{
+ struct stm32_uart *stm32 = to_stm32_uart(cdev);
+ void __iomem *base = stm32->base;
+ bool stm32f4 = stm32->stm32f4;
+
+ while (!(readl(base + ISR_OFFSET(stm32f4)) & USART_ISR_TXE));
+}
+
+static void stm32_serial_init(struct console_device *cdev)
+{
+ struct stm32_uart *stm32 = to_stm32_uart(cdev);
+ void __iomem *base = stm32->base;
+ bool stm32f4 = stm32->stm32f4;
+ u8 uart_enable_bit = stm32->uart_enable_bit;
+ u32 cr1;
+
+ cr1 = readl(base + CR1_OFFSET(stm32f4));
+
+ /* Disable uart-> enable fifo -> enable uart */
+ cr1 &= ~(USART_CR1_RE | USART_CR1_TE | BIT(uart_enable_bit));
+
+ writel(cr1, base + CR1_OFFSET(stm32f4));
+
+ if (stm32->has_fifo)
+ cr1 |= USART_CR1_FIFOEN;
+
+ cr1 &= ~(USART_CR1_PCE | USART_CR1_PS | USART_CR1_M1 | USART_CR1_M0);
+
+ cr1 |= USART_CR1_RE | USART_CR1_TE | BIT(uart_enable_bit);
+
+ writel(cr1, base + CR1_OFFSET(stm32f4));
+}
+
+static int stm32_serial_probe(struct device_d *dev)
+{
+ int ret;
+ struct console_device *cdev;
+ struct stm32_uart *stm32;
+ const char *devname;
+ struct resource *res;
+ struct stm32_uart_info *info;
+
+ ret = dev_get_drvdata(dev, (const void **)&info);
+ if (ret)
+ return ret;
+
+ stm32 = xzalloc(sizeof(*stm32));
+ cdev = &stm32->cdev;
+
+ res = dev_request_mem_resource(dev, 0);
+ if (IS_ERR(res)) {
+ ret = PTR_ERR(res);
+ goto err_free;
+ }
+ stm32->base = IOMEM(res->start);
+
+ stm32->has_fifo = info->has_fifo;
+ stm32->stm32f4 = info->stm32f4;
+ stm32->uart_enable_bit = info->uart_enable_bit;
+
+ stm32->clk = clk_get(dev, NULL);
+ if (IS_ERR(stm32->clk)) {
+ ret = PTR_ERR(stm32->clk);
+ dev_err(dev, "Failed to get UART clock %d\n", ret);
+ goto io_release;
+ }
+
+ ret = clk_enable(stm32->clk);
+ if (ret) {
+ dev_err(dev, "Failed to enable UART clock %d\n", ret);
+ goto io_release;
+ }
+
+ cdev->dev = dev;
+ cdev->tstc = stm32_serial_tstc;
+ cdev->putc = stm32_serial_putc;
+ cdev->getc = stm32_serial_getc;
+ cdev->flush = stm32_serial_flush;
+ cdev->setbrg = stm32_serial_setbaudrate;
+
+ if (dev->device_node) {
+ devname = of_alias_get(dev->device_node);
+ if (devname) {
+ cdev->devname = xstrdup(devname);
+ cdev->devid = DEVICE_ID_SINGLE;
+ }
+ }
+
+ stm32_serial_init(cdev);
+
+ ret = console_register(cdev);
+ if (!ret)
+ return 0;
+
+ clk_put(stm32->clk);
+io_release:
+ release_region(res);
+err_free:
+ free(stm32);
+
+ return ret;
+}
+
+struct stm32_uart_info stm32f4_info = {
+ .stm32f4 = true,
+ .uart_enable_bit = 13,
+ .has_fifo = false,
+};
+
+struct stm32_uart_info stm32f7_info = {
+ .uart_enable_bit = 0,
+ .stm32f4 = false,
+ .has_fifo = true,
+};
+
+struct stm32_uart_info stm32h7_info = {
+ .uart_enable_bit = 0,
+ .stm32f4 = false,
+ .has_fifo = true,
+};
+
+static struct of_device_id stm32_serial_dt_ids[] = {
+ {
+ .compatible = "st,stm32-uart",
+ .data = &stm32f4_info
+ }, {
+ .compatible = "st,stm32f7-uart",
+ .data = &stm32f7_info
+ }, {
+ .compatible = "st,stm32h7-uart",
+ .data = &stm32h7_info
+ }, {
+ }
+};
+
+static struct driver_d stm32_serial_driver = {
+ .name = "stm32-serial",
+ .probe = stm32_serial_probe,
+ .of_compatible = DRV_OF_COMPAT(stm32_serial_dt_ids),
+};
+console_platform_driver(stm32_serial_driver);