[U-Boot] [PATCH 1/4 v3] serial: Add Zynq serial driver

Marek Vasut
2012-09-14T07:45:09Z

Dear Michal Simek,

> The driver is used on Xilinx Zynq platform.
>
> Signed-off-by: Michal Simek <monstr@monstr.eu>
> CC: Joe Hershberger <joe.hershberger@gmail.com>
> CC: Marek Vasut <marex@denx.de>
>
> ---
> v2: Use Zynq name instead of Dragonfire and XPSS/XDFUART
> Rename driver name
> Remove driver description
>
> v3: SERIAL_MULTI support
> Rename xdfuart to uart_zynq
> ---
> common/serial.c | 8 ++
> drivers/serial/Makefile | 1 +
> drivers/serial/serial_zynq.c | 246
> ++++++++++++++++++++++++++++++++++++++++++ include/serial.h |
> 5 +
> 4 files changed, 260 insertions(+), 0 deletions(-)
> create mode 100644 drivers/serial/serial_zynq.c
>
> diff --git a/common/serial.c b/common/serial.c
> index 75cc1bb..4f2bc7f 100644
> --- a/common/serial.c
> +++ b/common/serial.c
> @@ -122,6 +122,14 @@ void serial_initialize(void)
> serial_register(&uartlite_serial3_device);
> # endif /* XILINX_UARTLITE_BASEADDR3 */
> #endif /* CONFIG_XILINX_UARTLITE */
> +#if defined(CONFIG_ZYNQ_SERIAL)
> +# ifdef CONFIG_ZYNQ_SERIAL_BASEADDR0
> + serial_register(&uart_zynq_serial0_device);
> +# endif
> +# ifdef CONFIG_ZYNQ_SERIAL_BASEADDR1
> + serial_register(&uart_zynq_serial1_device);
> +# endif
> +#endif
> serial_assign(default_serial_console()->name);
> }
>
> diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
> index 65d0f23..dfc22a4 100644
> --- a/drivers/serial/Makefile
> +++ b/drivers/serial/Makefile
> @@ -56,6 +56,7 @@ COBJS-$(CONFIG_S3C44B0_SERIAL) += serial_s3c44b0.o
> COBJS-$(CONFIG_XILINX_UARTLITE) += serial_xuartlite.o
> COBJS-$(CONFIG_SANDBOX_SERIAL) += sandbox.o
> COBJS-$(CONFIG_SCIF_CONSOLE) += serial_sh.o
> +COBJS-$(CONFIG_ZYNQ_SERIAL) += serial_zynq.o
>
> ifndef CONFIG_SPL_BUILD
> COBJS-$(CONFIG_USB_TTY) += usbtty.o
> diff --git a/drivers/serial/serial_zynq.c b/drivers/serial/serial_zynq.c
> new file mode 100644
> index 0000000..30f2445
> --- /dev/null
> +++ b/drivers/serial/serial_zynq.c
> @@ -0,0 +1,246 @@
> +/*
> + * Copyright (C) 2012 Michal Simek <monstr@monstr.eu>
> + * Copyright (C) 2011-2012 Xilinx, Inc. All rights reserved.
> + *
> + * See file CREDITS for list of people who contributed to this
> + * project.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
> + * MA 02111-1307 USA
> + */
> +
> +#include <common.h>
> +#include <watchdog.h>
> +#include <asm/io.h>
> +#include <linux/compiler.h>
> +#include <serial.h>
> +
> +#define ZYNQ_UART_SR_TXFULL 0x00000010 /* TX FIFO full */
> +#define ZYNQ_UART_SR_RXEMPTY 0x00000002 /* RX FIFO empty */
> +
> +#define ZYNQ_UART_CR_TX_EN 0x00000010 /* TX enabled */
> +#define ZYNQ_UART_CR_RX_EN 0x00000004 /* RX enabled */
> +#define ZYNQ_UART_CR_TXRST 0x00000002 /* TX logic reset */
> +#define ZYNQ_UART_CR_RXRST 0x00000001 /* RX logic reset */
> +
> +#define ZYNQ_UART_MR_PARITY_NONE 0x00000020 /* No parity mode */
> +
> +/* Some clock/baud constants */
> +#define ZYNQ_UART_BDIV 15 /* Default/reset BDIV value */
> +#define ZYNQ_UART_BASECLK 3125000L /* master / (bdiv + 1) */
> +
> +struct uart_zynq {
> + u32 control; /* Control Register [8:0] */
> + u32 mode; /* Mode Register [10:0] */
> + u32 reserved1[4];
> + u32 baud_rate_gen; /* Baud Rate Generator [15:0] */
> + u32 reserved2[4];
> + u32 channel_sts; /* Channel Status [11:0] */
> + u32 tx_rx_fifo; /* FIFO [15:0] or [7:0] */
> + u32 baud_rate_divider; /* Baud Rate Divider [7:0] */
> +};
> +
> +static struct uart_zynq *uart_zynq_ports[2] = {
> +#ifdef CONFIG_ZYNQ_SERIAL_BASEADDR0
> + [0] = (struct uart_zynq *)CONFIG_ZYNQ_SERIAL_BASEADDR0,
> +#endif
> +#ifdef CONFIG_ZYNQ_SERIAL_BASEADDR1
> + [1] = (struct uart_zynq *)CONFIG_ZYNQ_SERIAL_BASEADDR1,
> +#endif
> +};
> +
> +struct uart_zynq_params {
> + u32 baudrate;
> + u32 clock;
> +};
> +
> +static struct uart_zynq_params uart_zynq_ports_param[2] = {
> +#if defined(CONFIG_ZYNQ_SERIAL_BAUDRATE0) &&
> defined(CONFIG_ZYNQ_SERIAL_CLOCK0) + [0].baudrate =
> CONFIG_ZYNQ_SERIAL_BAUDRATE0,
> + [0].clock = CONFIG_ZYNQ_SERIAL_CLOCK0,
> +#endif
> +#if defined(CONFIG_ZYNQ_SERIAL_BAUDRATE1) &&
> defined(CONFIG_ZYNQ_SERIAL_CLOCK1) + [1].baudrate =
> CONFIG_ZYNQ_SERIAL_BAUDRATE1,
> + [1].clock = CONFIG_ZYNQ_SERIAL_CLOCK1,
> +#endif
> +};
> +
> +/* Set up the baud rate in gd struct */
> +static void uart_zynq_serial_setbrg(const int port)
> +{
> + /* Calculation results. */
> + unsigned int calc_bauderror, bdiv, bgen;
> + unsigned long calc_baud = 0;
> + unsigned long baud = uart_zynq_ports_param[port].baudrate;
> + unsigned long clock = uart_zynq_ports_param[port].clock;
> + struct uart_zynq *regs = uart_zynq_ports[port];
> +
> + /* master clock
> + * Baud rate = ------------------
> + * bgen * (bdiv + 1)
> + *
> + * Find acceptable values for baud generation.
> + */
> + for (bdiv = 4; bdiv < 255; bdiv++) {
> + bgen = clock / (baud * (bdiv + 1));
> + if (bgen < 2 || bgen > 65535)
> + continue;
> +
> + calc_baud = clock / (bgen * (bdiv + 1));
> +
> + /*
> + * Use first calculated baudrate with
> + * an acceptable (<3%) error
> + */
> + if (baud > calc_baud)
> + calc_bauderror = baud - calc_baud;
> + else
> + calc_bauderror = calc_baud - baud;
> + if (((calc_bauderror * 100) / baud) < 3)
> + break;
> + }
> +
> + writel(bdiv, &regs->baud_rate_divider);
> + writel(bgen, &regs->baud_rate_gen);
> +}
> +
> +/* Initialize the UART, with...some settings. */
> +static int uart_zynq_serial_init(const int port)
> +{
> + struct uart_zynq *regs = uart_zynq_ports[port];
> +
> + if (!regs)
> + return -1;
> +
> + /* RX/TX enabled & reset */
> + writel(ZYNQ_UART_CR_TX_EN | ZYNQ_UART_CR_RX_EN | ZYNQ_UART_CR_TXRST | \
> + ZYNQ_UART_CR_RXRST, &regs->control);
> + writel(ZYNQ_UART_MR_PARITY_NONE, &regs->mode); /* 8 bit, no parity */
> + uart_zynq_serial_setbrg(port);
> +
> + return 0;
> +}
> +
> +static void uart_zynq_serial_putc(const char c, const int port)
> +{
> + struct uart_zynq *regs = uart_zynq_ports[port];
> +
> + while ((readl(&regs->channel_sts) & ZYNQ_UART_SR_TXFULL) != 0)
> + WATCHDOG_RESET();
> +
> + if (c == '\n') {
> + writel('\r', &regs->tx_rx_fifo);
> + while ((readl(&regs->channel_sts) & ZYNQ_UART_SR_TXFULL) != 0)
> + WATCHDOG_RESET();
> + }
> + writel(c, &regs->tx_rx_fifo);
> +}
> +
> +static void uart_zynq_serial_puts(const char *s, const int port)
> +{
> + while (*s)
> + uart_zynq_serial_putc(*s++, port);
> +}

Remark for myself ... squash all these while (*s) putc() constructs into serial
core. I'll be adding a patch into my massive patchset I'm cooking for this, you
don't worry as this is ok for now.

> +static int uart_zynq_serial_tstc(const int port)
> +{
> + struct uart_zynq *regs = uart_zynq_ports[port];
> +
> + return (readl(&regs->channel_sts) & ZYNQ_UART_SR_RXEMPTY) == 0;
> +}
> +
> +static int uart_zynq_serial_getc(const int port)
> +{
> + struct uart_zynq *regs = uart_zynq_ports[port];
> +
> + while (!uart_zynq_serial_tstc(port))
> + WATCHDOG_RESET();
> + return readl(&regs->tx_rx_fifo);
> +}
> +
> +#if !defined(CONFIG_SERIAL_MULTI)
> +int serial_init(void)
> +{
> + return uart_zynq_serial_init(0);
> +}
> +
> +void serial_setbrg(void)
> +{
> + uart_zynq_serial_setbrg(0);
> +}
> +
> +void serial_putc(const char c)
> +{
> + uart_zynq_serial_putc(c, 0);
> +}
> +
> +void serial_puts(const char *s)
> +{
> + uart_zynq_serial_puts(s, 0);
> +}
> +
> +int serial_getc(void)
> +{
> + return uart_zynq_serial_getc(0);
> +}
> +
> +int serial_tstc(void)
> +{
> + return uart_zynq_serial_tstc(0);
> +}
> +#else
> +/* Multi serial device functions */
> +#define DECLARE_PSSERIAL_FUNCTIONS(port) \
> + int uart_zynq##port##_init(void) \
> + { return uart_zynq_serial_init(port); } \
> + void uart_zynq##port##_setbrg(void) \
> + { return uart_zynq_serial_setbrg(port); } \
> + int uart_zynq##port##_getc(void) \
> + { return uart_zynq_serial_getc(port); } \
> + int uart_zynq##port##_tstc(void) \
> + { return uart_zynq_serial_tstc(port); } \
> + void uart_zynq##port##_putc(const char c) \
> + { uart_zynq_serial_putc(c, port); } \
> + void uart_zynq##port##_puts(const char *s) \
> + { uart_zynq_serial_puts(s, port); }
> +
> +/* Serial device descriptor */
> +#define INIT_PSSERIAL_STRUCTURE(port, name) {\

Rename the "name" to __name (this is because once you rename it -- see below --
name will colide with .name)

> + name,\

explicitly spell out the name of structure members, so the structure instance is
agile to reordering the the declaration members.

> + uart_zynq##port##_init,\
> + NULL,\
> + uart_zynq##port##_setbrg,\
> + uart_zynq##port##_getc,\
> + uart_zynq##port##_tstc,\
> + uart_zynq##port##_putc,\
> + uart_zynq##port##_puts, }
> +
> +DECLARE_PSSERIAL_FUNCTIONS(0);
> +struct serial_device uart_zynq_serial0_device =
> + INIT_PSSERIAL_STRUCTURE(0, "ttyPS0");
> +DECLARE_PSSERIAL_FUNCTIONS(1);
> +struct serial_device uart_zynq_serial1_device =
> + INIT_PSSERIAL_STRUCTURE(1, "ttyPS1");
> +
> +__weak struct serial_device *default_serial_console(void)
> +{
> + if (uart_zynq_ports[0])
> + return &uart_zynq_serial0_device;
> + if (uart_zynq_ports[1])
> + return &uart_zynq_serial1_device;
> +
> + return NULL;
> +}
> +#endif
> diff --git a/include/serial.h b/include/serial.h
> index cbdf8a9..dc8e9b4 100644
> --- a/include/serial.h
> +++ b/include/serial.h
> @@ -89,6 +89,11 @@ extern struct serial_device bfin_serial2_device;
> extern struct serial_device bfin_serial3_device;
> #endif
>
> +#if defined(CONFIG_ZYNQ_SERIAL)
> +extern struct serial_device uart_zynq_serial0_device;
> +extern struct serial_device uart_zynq_serial1_device;
> +#endif
> +

Let's not add this, noone uses it.

> extern void serial_register(struct serial_device *);
> extern void serial_initialize(void);
> extern void serial_stdio_init(void);