[U-Boot] [PATCH v2 04/14] serial: add serial driver for BCM6345

Álvaro Fernández Rojas
2017-04-15T22:03:56Z

It is based on linux/drivers/tty/serial/bcm63xx_uart.c

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
---
v2: Introduce changes suggested by Daniel Schwierzeck:
- Remove unneeded defines.
- Fix incorrect multi-line comment.

drivers/serial/Kconfig | 14 +++
drivers/serial/Makefile | 1 +
drivers/serial/serial_bcm6345.c | 267 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 282 insertions(+)
create mode 100644 drivers/serial/serial_bcm6345.c

diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index c0ec2ec..ca776d8 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -134,6 +134,14 @@ config DEBUG_UART_ATMEL
will need to provide parameters to make this work. The driver will
be available until the real driver-model serial is running.

+config DEBUG_UART_BCM6345
+ bool "BCM6345 UART"
+ depends on BCM6345_SERIAL
+ help
+ Select this to enable a debug UART on BCM6345 SoCs. You
+ will need to provide parameters to make this work. The driver will
+ be available until the real driver model serial is running.
+
config DEBUG_UART_NS16550
bool "ns16550"
help
@@ -339,6 +347,12 @@ config ATMEL_USART
configured in the device tree, and input clock frequency can
be got from the clk node.

+config BCM6345_SERIAL
+ bool "Support for BCM6345 UART"
+ depends on DM_SERIAL
+ help
+ Select this to enable UART on BCM6345 SoCs.
+
config FSL_LPUART
bool "Freescale LPUART support"
help
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index 4382cf9..dca31b2 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_ALTERA_JTAG_UART) += altera_jtag_uart.o
obj-$(CONFIG_AR933X_UART) += serial_ar933x.o
obj-$(CONFIG_ARM_DCC) += arm_dcc.o
obj-$(CONFIG_ATMEL_USART) += atmel_usart.o
+obj-$(CONFIG_BCM6345_SERIAL) += serial_bcm6345.o
obj-$(CONFIG_EFI_APP) += serial_efi.o
obj-$(CONFIG_LPC32XX_HSUART) += lpc32xx_hsuart.o
obj-$(CONFIG_MCFUART) += mcfuart.o
diff --git a/drivers/serial/serial_bcm6345.c b/drivers/serial/serial_bcm6345.c
new file mode 100644
index 0000000..fa1e3e3
--- /dev/null
+++ b/drivers/serial/serial_bcm6345.c
@@ -0,0 +1,267 @@
+/*
+ * Copyright (C) 2017 Álvaro Fernández Rojas <noltari@gmail.com>
+ *
+ * Derived from linux/drivers/tty/serial/bcm63xx_uart.c:
+ * Copyright (C) 2008 Maxime Bizon <mbizon@freebox.fr>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <clk.h>
+#include <debug_uart.h>
+#include <errno.h>
+#include <serial.h>
+#include <asm/io.h>
+#include <asm/types.h>
+#include <dm/device.h>
+
+/* UART Control Register */
+#define UART_CTL_REG 0x0
+#define UART_CTL_RSTRXFIFO_SHIFT 6
+#define UART_CTL_RSTRXFIFO_MASK (1 << UART_CTL_RSTRXFIFO_SHIFT)
+#define UART_CTL_RSTTXFIFO_SHIFT 7
+#define UART_CTL_RSTTXFIFO_MASK (1 << UART_CTL_RSTTXFIFO_SHIFT)
+#define UART_CTL_STOPBITS_SHIFT 8
+#define UART_CTL_STOPBITS_MASK (0xf << UART_CTL_STOPBITS_SHIFT)
+#define UART_CTL_STOPBITS_1 (0x7 << UART_CTL_STOPBITS_SHIFT)
+#define UART_CTL_BITSPERSYM_SHIFT 12
+#define UART_CTL_BITSPERSYM_MASK (0x3 << UART_CTL_BITSPERSYM_SHIFT)
+#define UART_CTL_RXEN_SHIFT 21
+#define UART_CTL_RXEN_MASK (1 << UART_CTL_RXEN_SHIFT)
+#define UART_CTL_TXEN_SHIFT 22
+#define UART_CTL_TXEN_MASK (1 << UART_CTL_TXEN_SHIFT)
+#define UART_CTL_BRGEN_SHIFT 23
+#define UART_CTL_BRGEN_MASK (1 << UART_CTL_BRGEN_SHIFT)
+
+/* UART Baudword register */
+#define UART_BAUD_REG 0x4
+
+/* UART Interrupt register */
+#define UART_IR_REG 0x10
+#define UART_IR_STAT(x) (1 << (x))
+#define UART_IR_TXEMPTY 5
+#define UART_IR_RXOVER 7
+#define UART_IR_RXNOTEMPTY 11
+
+/* UART Fifo register */
+#define UART_FIFO_REG 0x14
+#define UART_FIFO_VALID_MASK 0xff
+#define UART_FIFO_FRAMEERR_SHIFT 8
+#define UART_FIFO_FRAMEERR_MASK (1 << UART_FIFO_FRAMEERR_SHIFT)
+#define UART_FIFO_PARERR_SHIFT 9
+#define UART_FIFO_PARERR_MASK (1 << UART_FIFO_PARERR_SHIFT)
+#define UART_FIFO_BRKDET_SHIFT 10
+#define UART_FIFO_BRKDET_MASK (1 << UART_FIFO_BRKDET_SHIFT)
+#define UART_FIFO_ANYERR_MASK (UART_FIFO_FRAMEERR_MASK | \
+ UART_FIFO_PARERR_MASK | \
+ UART_FIFO_BRKDET_MASK)
+
+struct bcm6345_serial_priv {
+ void __iomem *base;
+ ulong uartclk;
+};
+
+/*
+ * enable rx & tx operation on uart
+ */
+static void bcm6345_serial_enable(void __iomem *base)
+{
+ u32 val;
+
+ val = __raw_readl(base + UART_CTL_REG);
+ val |= (UART_CTL_BRGEN_MASK | UART_CTL_TXEN_MASK | UART_CTL_RXEN_MASK);
+ __raw_writel(val, base + UART_CTL_REG);
+}
+
+/*
+ * disable rx & tx operation on uart
+ */
+static void bcm6345_serial_disable(void __iomem *base)
+{
+ u32 val;
+
+ val = __raw_readl(base + UART_CTL_REG);
+ val &= ~(UART_CTL_BRGEN_MASK | UART_CTL_TXEN_MASK |
+ UART_CTL_RXEN_MASK);
+ __raw_writel(val, base + UART_CTL_REG);
+}
+
+/*
+ * clear all unread data in rx fifo and unsent data in tx fifo
+ */
+static void bcm6345_serial_flush(void __iomem *base)
+{
+ u32 val;
+
+ /* empty rx and tx fifo */
+ val = __raw_readl(base + UART_CTL_REG);
+ val |= UART_CTL_RSTRXFIFO_MASK | UART_CTL_RSTTXFIFO_MASK;
+ __raw_writel(val, base + UART_CTL_REG);
+
+ /* read any pending char to make sure all irq status are cleared */
+ __raw_readl(base + UART_FIFO_REG);
+}
+
+static int bcm6345_serial_init(void __iomem *base, ulong clk, u32 baudrate)
+{
+ u32 val;
+
+ /* mask all irq and flush port */
+ bcm6345_serial_disable(base);
+ bcm6345_serial_flush(base);
+
+ /* set bits per sym and stop bits */
+ val = __raw_readl(base + UART_CTL_REG);
+ val &= ~UART_CTL_BITSPERSYM_MASK;
+ val |= (3 << UART_CTL_BITSPERSYM_SHIFT);
+ val &= ~UART_CTL_STOPBITS_MASK;
+ val |= UART_CTL_STOPBITS_1;
+ __raw_writel(val, base + UART_CTL_REG);
+
+ /* set baud rate */
+ val = (clk / baudrate) / 16;
+ if (val & 0x1)
+ val = val;
+ else
+ val = val / 2 - 1;
+ __raw_writel(val, base + UART_BAUD_REG);
+
+ /* clear interrupts */
+ __raw_writel(0, base + UART_IR_REG);
+
+ /* enable uart */
+ bcm6345_serial_enable(base);
+
+ return 0;
+}
+
+static int bcm6345_serial_pending(struct udevice *dev, bool input)
+{
+ struct bcm6345_serial_priv *priv = dev_get_priv(dev);
+ u32 val = __raw_readl(priv->base + UART_IR_REG);
+
+ if (input)
+ return (val & UART_IR_STAT(UART_IR_RXNOTEMPTY)) ? 1 : 0;
+ else
+ return (val & UART_IR_STAT(UART_IR_TXEMPTY)) ? 0 : 1;
+}
+
+static int bcm6345_serial_setbrg(struct udevice *dev, int baudrate)
+{
+ struct bcm6345_serial_priv *priv = dev_get_priv(dev);
+
+ return bcm6345_serial_init(priv->base, priv->uartclk, baudrate);
+}
+
+static int bcm6345_serial_putc(struct udevice *dev, const char ch)
+{
+ struct bcm6345_serial_priv *priv = dev_get_priv(dev);
+ u32 val;
+
+ val = __raw_readl(priv->base + UART_IR_REG);
+ if (!(val & UART_IR_STAT(UART_IR_TXEMPTY)))
+ return -EAGAIN;
+
+ __raw_writel(ch, priv->base + UART_FIFO_REG);
+
+ return 0;
+}
+
+static int bcm6345_serial_getc(struct udevice *dev)
+{
+ struct bcm6345_serial_priv *priv = dev_get_priv(dev);
+ u32 val;
+
+ val = __raw_readl(priv->base + UART_IR_REG);
+ if (val & UART_IR_STAT(UART_IR_RXOVER)) {
+ /* fifo reset is required to clear interrupt */
+ val = __raw_readl(priv->base + UART_CTL_REG);
+ val |= UART_CTL_RSTRXFIFO_MASK;
+ __raw_writel(val, priv->base + UART_CTL_REG);
+ }
+ if (!(val & UART_IR_STAT(UART_IR_RXNOTEMPTY)))
+ return -EAGAIN;
+
+ val = __raw_readl(priv->base + UART_FIFO_REG);
+ if (val & UART_FIFO_ANYERR_MASK)
+ return -EAGAIN;
+
+ return (val & UART_FIFO_VALID_MASK);
+}
+
+static int bcm6345_serial_probe(struct udevice *dev)
+{
+ struct bcm6345_serial_priv *priv = dev_get_priv(dev);
+ struct clk clk;
+ fdt_addr_t addr;
+ fdt_size_t size;
+ int ret;
+
+ /* get address */
+ addr = dev_get_addr_size_index(dev, 0, &size);
+ if (addr == FDT_ADDR_T_NONE)
+ return -EINVAL;
+
+ priv->base = ioremap(addr, size);
+
+ /* get clock rate */
+ ret = clk_get_by_index(dev, 0, &clk);
+ if (ret < 0)
+ return ret;
+ priv->uartclk = clk_get_rate(&clk) / 2;
+ clk_free(&clk);
+
+ /* initialize serial */
+ return bcm6345_serial_init(priv->base, priv->uartclk, CONFIG_BAUDRATE);
+}
+
+static const struct dm_serial_ops bcm6345_serial_ops = {
+ .putc = bcm6345_serial_putc,
+ .pending = bcm6345_serial_pending,
+ .getc = bcm6345_serial_getc,
+ .setbrg = bcm6345_serial_setbrg,
+};
+
+static const struct udevice_id bcm6345_serial_of_match[] = {
+ { .compatible = "brcm,bcm6345-uart" },
+ { /* sentinel */ }
+};
+
+U_BOOT_DRIVER(bcm6345_serial) = {
+ .name = "bcm6345-uart",
+ .id = UCLASS_SERIAL,
+ .of_match = bcm6345_serial_of_match,
+ .probe = bcm6345_serial_probe,
+ .priv_auto_alloc_size = sizeof(struct bcm6345_serial_priv),
+ .ops = &bcm6345_serial_ops,
+ .flags = DM_FLAG_PRE_RELOC,
+};
+
+#ifdef CONFIG_DEBUG_UART_BCM6345
+static inline void _debug_uart_init(void)
+{
+ void __iomem *base = (void __iomem *)CONFIG_DEBUG_UART_BASE;
+
+ bcm6345_serial_init(base, CONFIG_DEBUG_UART_CLOCK, CONFIG_BAUDRATE);
+}
+
+static inline void wait_xfered(void __iomem *base)
+{
+ do {
+ u32 val = __raw_readl(base + UART_IR_REG);
+ if (val & UART_IR_STAT(UART_IR_TXEMPTY))
+ break;
+ } while (1);
+}
+
+static inline void _debug_uart_putc(int ch)
+{
+ void __iomem *base = (void __iomem *)CONFIG_DEBUG_UART_BASE;
+
+ wait_xfered(base);
+ __raw_writel(ch, base + UART_FIFO_REG);
+ wait_xfered(base);
+}
+
+DEBUG_UART_FUNCS
+#endif
--
2.1.4