Re: [U-Boot] [PATCH v3 06/14] drivers: serial: add driver for Microchip PIC32 UART controller.

Am Dienstag, den 12.01.2016, 15:48 +0530 schrieb Purna Chandra Mandal:

From: Paul Thacker paul.thacker@microchip.com

This adds PIC32 UART controller support based on driver model.

Signed-off-by: Paul Thacker paul.thacker@microchip.com Signed-off-by: Purna Chandra Mandal purna.mandal@microchip.com

Reviewed-by: Daniel Schwierzeck daniel.schwierzeck@gmail.com

nits below

---

Changes in v3:

• remove ofdata_to_platdata, and replace platdata with priv
• remove special handling of '\r' as being handled by serial-uclass
• remove loop to wait for space in tx buffer before pumping char

Changes in v2:

• fix missing/corrupted chars during baud rate change
• remove loop until any char is avaialbale in getc()

.../serial/microchip,pic32-uart.txt | 5 + drivers/serial/Kconfig | 13 ++ drivers/serial/Makefile | 1 + drivers/serial/serial_pic32.c | 199 +++++++++++++++++++++ 4 files changed, 218 insertions(+) create mode 100644 doc/device-tree-bindings/serial/microchip,pic32 -uart.txt create mode 100644 drivers/serial/serial_pic32.c

diff --git a/doc/device-tree-bindings/serial/microchip,pic32-uart.txt b/doc/device-tree-bindings/serial/microchip,pic32-uart.txt new file mode 100644 index 0000000..f00e215 --- /dev/null +++ b/doc/device-tree-bindings/serial/microchip,pic32-uart.txt @@ -0,0 +1,5 @@ +* Microchip PIC32 serial UART

+Required properties: +- compatible: must be "microchip,pic32mzda-uart". +- reg: exactly one register range. diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig index 1fc287e..9763ea1 100644 --- a/drivers/serial/Kconfig +++ b/drivers/serial/Kconfig @@ -107,6 +107,14 @@ config DEBUG_UART_APBUART 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_PIC32

• bool "Microchip PIC32"
• help

•  Select this to enable a debug UART using the serial_pic32
  

driver. You

•  will need to provide parameters to make this work. The
  

driver will

•  be available until the real driver model serial is
  

running.

endchoice

config DEBUG_UART_BASE @@ -223,4 +231,9 @@ config UNIPHIER_SERIAL If you have a UniPhier based board and want to use the on -chip serial ports, say Y to this option. If unsure, say N.

+config PIC32_SERIAL

• bool "Support for Microchip PIC32 on-chip UART"
• help

•  Support for the UART found on Microchip PIC32 SoC's.
  

endmenu diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile index dd87147..57cd38b 100644 --- a/drivers/serial/Makefile +++ b/drivers/serial/Makefile @@ -41,6 +41,7 @@ obj-$(CONFIG_MXS_AUART) += mxs_auart.o obj-$(CONFIG_ARC_SERIAL) += serial_arc.o obj-$(CONFIG_UNIPHIER_SERIAL) += serial_uniphier.o obj-$(CONFIG_STM32_SERIAL) += serial_stm32.o +obj-$(CONFIG_PIC32_SERIAL) += serial_pic32.o

ifndef CONFIG_SPL_BUILD obj-$(CONFIG_USB_TTY) += usbtty.o diff --git a/drivers/serial/serial_pic32.c b/drivers/serial/serial_pic32.c new file mode 100644 index 0000000..ee9d056 --- /dev/null +++ b/drivers/serial/serial_pic32.c @@ -0,0 +1,199 @@ +/*

• • (c) 2015 Paul Thacker paul.thacker@microchip.com
• • SPDX-License-Identifier: GPL-2.0+
• */

+#include <common.h> +#include <clk.h> +#include <dm.h> +#include <serial.h> +#include <wait_bit.h> +#include <mach/pic32.h> +#include <dt-bindings/clock/microchip,clock.h>

+DECLARE_GLOBAL_DATA_PTR;

+/* UART Control Registers */ +#define U_MOD 0x00 +#define U_MODCLR (U_MOD + _CLR_OFFSET) +#define U_MODSET (U_MOD + _SET_OFFSET) +#define U_STA 0x10 +#define U_STACLR (U_STA + _CLR_OFFSET) +#define U_STASET (U_STA + _SET_OFFSET) +#define U_TXR 0x20 +#define U_RXR 0x30 +#define U_BRG 0x40

+/* U_MOD bits */ +#define UART_ENABLE BIT(15)

+/* U_STA bits */ +#define UART_RX_ENABLE BIT(12) +#define UART_TX_BRK BIT(11) +#define UART_TX_ENABLE BIT(10) +#define UART_TX_FULL BIT(9) +#define UART_TX_EMPTY BIT(8) +#define UART_RX_OERR BIT(1) +#define UART_RX_DATA_AVAIL BIT(0)

+struct pic32_uart_priv {

• void __iomem *base;
• ulong uartclk;

+};

+/*

• • Initialize the serial port with the given baudrate.
• • The settings are always 8 data bits, no parity, 1 stop bit, no

start bits.

• */

+static int pic32_serial_init(void __iomem *base, ulong clk, u32 baudrate) +{

• u32 div = DIV_ROUND_CLOSEST(clk, baudrate * 16);
• /* wait for TX FIFO to empty */
• wait_for_bit(__func__, base + U_STA, UART_TX_EMPTY,

•      true, CONFIG_SYS_HZ, false);
  

• /* send break */
• writel(UART_TX_BRK, base + U_STASET);
• /* disable and clear mode */
• writel(0, base + U_MOD);
• writel(0, base + U_STA);
• /* set baud rate generator */
• writel(div - 1, base + U_BRG);
• /* enable the UART for TX and RX */
• writel(UART_TX_ENABLE | UART_RX_ENABLE, base + U_STASET);
• /* enable the UART */
• writel(UART_ENABLE, base + U_MODSET);
• return 0;

+}

+/* Check number of characters ready in RX Fifo */ +static int pic32_uart_pending_input(void __iomem *base) +{

• /* check if rx buffer overrun error has occurred */
• if (readl(base + U_STA) & UART_RX_OERR) {

• readl(base + U_RXR);
  

• /* clear OERR to keep receiving */
  

• writel(UART_RX_OERR, base + U_STACLR);
  

• }
• return readl(base + U_STA) & UART_RX_DATA_AVAIL;

+}

+static int pic32_uart_pending(struct udevice *dev, bool input) +{

• struct pic32_uart_priv *priv = dev_get_priv(dev);
• if (input)

• return pic32_uart_pending_input(priv->base);
  

• return !(readl(priv->base + U_STA) & UART_TX_EMPTY);

+}

+static int pic32_uart_setbrg(struct udevice *dev, int baudrate) +{

• struct pic32_uart_priv *priv = dev_get_priv(dev);
• return pic32_serial_init(priv->base, priv->uartclk,

baudrate); +}

+static int pic32_uart_putc(struct udevice *dev, const char ch) +{

• struct pic32_uart_priv *priv = dev_get_priv(dev);
• /* Check if Tx FIFO is full */
• if (readl(priv->base + U_STA) & UART_TX_FULL)

• return -EAGAIN;
  

• /* pump the char to tx buffer */
• writel(ch, priv->base + U_TXR);
• return 0;

+}

+static int pic32_uart_getc(struct udevice *dev) +{

• struct pic32_uart_priv *priv = dev_get_priv(dev);
• /* return error if RX fifo is empty */
• if (!pic32_uart_pending_input(priv->base))

• return -EAGAIN;
  

• /* read the character from rx buffer */
• return readl(priv->base + U_RXR) & 0xff;

+}

+static int pic32_uart_probe(struct udevice *dev) +{

• struct pic32_uart_priv *priv = dev_get_priv(dev);
• struct udevice *clkdev;
• fdt_addr_t addr;
• fdt_size_t size;
• int ret;
• /* get address */
• addr = fdtdec_get_addr_size(gd->fdt_blob, dev->of_offset,

"reg", &size);

• if (addr == FDT_ADDR_T_NONE)

• return -EINVAL;
  

• priv->base = ioremap(addr, size);
• if (!priv->base)

• return -EINVAL;
  

you can drop this check. ioremap() always returns a mapped address.

• /* get clock rate */
• ret = uclass_get_device(UCLASS_CLK, 0, &clkdev);
• if (ret) {

• printf("clk class not found, %d\n", ret);
  

• return ret;
  

• }
• priv->uartclk = clk_get_periph_rate(clkdev, PB2CLK);
• /* initialize serial */
• return pic32_serial_init(priv->base, priv->uartclk,

CONFIG_BAUDRATE); +}

+static const struct dm_serial_ops pic32_uart_ops = {

• .putc = pic32_uart_putc,
• .pending = pic32_uart_pending,
• .getc = pic32_uart_getc,
• .setbrg = pic32_uart_setbrg,

+};

+static const struct udevice_id pic32_uart_ids[] = {

• { .compatible = "microchip,pic32mzda-uart" },
• {}

+};

+U_BOOT_DRIVER(pic32_serial) = {

• .name = "pic32-uart",
• .id = UCLASS_SERIAL,
• .of_match = pic32_uart_ids,
• .probe = pic32_uart_probe,
• .ops = &pic32_uart_ops,
• .flags = DM_FLAG_PRE_RELOC,
• .priv_auto_alloc_size = sizeof(struct pic32_uart_priv),

+};

+#ifdef CONFIG_DEBUG_UART_PIC32 +#include <debug_uart.h>

+static inline void _debug_uart_init(void) +{

• void __iomem *base = (void __iomem *)CONFIG_DEBUG_UART_BASE;
• pic32_serial_init(base, CONFIG_DEBUG_UART_CLOCK,

CONFIG_BAUDRATE); +}

+static inline void _debug_uart_putc(int ch) +{

• writel(ch, CONFIG_DEBUG_UART_BASE + U_TXR);

+}

+DEBUG_UART_FUNCS +#endif