Re: [PATCH] Au1x00 8250 uart support.

[Russell King <rmk+lkml@arm.linux.org.uk>]

On Mon, Sep 19, 2005 at 11:40:10PM +0300, Pantelis Antoniou wrote:
> diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
> --- a/drivers/serial/8250.c
> +++ b/drivers/serial/8250.c
> @@ -249,10 +249,42 @@ static const struct serial8250_config ua
>  		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
>  		.flags		= UART_CAP_FIFO | UART_CAP_UUE,
>  	},
> +	[PORT_AU1X00] = {
> +		.name		= "Au1x00",
> +		.fifo_size	= 16,
> +		.tx_loadsz	= 16,
> +		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
> +		.flags		= UART_CAP_FIFO | UART_CAP_NOMSR,
> +	},
> +};
> +
> +#ifdef CONFIG_SERIAL_8250_AU1X00
> +static const u8 au_io_in_map[] = {
> +	[UART_RX]  = 0,
> +	[UART_IER] = 2,
> +	[UART_IIR] = 3,
> +	[UART_LCR] = 5,
> +	[UART_MCR] = 6,
> +	[UART_LSR] = 7,
> +	[UART_MSR] = 8,
>  };
>  
> +static const u8 au_io_out_map[] = {
> +	[UART_TX]  = 1,
> +	[UART_IER] = 2,
> +	[UART_FCR] = 4,
> +	[UART_LCR] = 5,
> +	[UART_MCR] = 6,
> +};
> +#endif
> +
>  static _INLINE_ unsigned int serial_in(struct uart_8250_port *up, int offset)
>  {
> +#ifdef CONFIG_SERIAL_8250_AU1X00
> +	if (up->port.iotype == UPIO_AU)
> +		offset = au_io_in_map[offset];
> +#endif
> +
>  	offset <<= up->port.regshift;
>  
>  	switch (up->port.iotype) {
> @@ -266,6 +298,11 @@ static _INLINE_ unsigned int serial_in(s
>  	case UPIO_MEM32:
>  		return readl(up->port.membase + offset);
>  
> +#ifdef CONFIG_SERIAL_8250_AU1X00
> +	case UPIO_AU:
> +		return __raw_readl(up->port.membase + offset);
> +#endif
> +

At some point, we probably want to make this non-AU1x00 specific, but
it may as well wait until someone else has such quirkyness themselves.
It would be nice to pass the maps in somehow, but that's a fair re-jig
of the interfaces to other chunks of code elsewhere in the kernel tree.
Therefore, I think it's a change we should not make until there's a
reason to make it.

>  	default:
>  		return inb(up->port.iobase + offset);
>  	}
> @@ -274,6 +311,11 @@ static _INLINE_ unsigned int serial_in(s
>  static _INLINE_ void
>  serial_out(struct uart_8250_port *up, int offset, int value)
>  {
> +#ifdef CONFIG_SERIAL_8250_AU1X00
> +	if (up->port.iotype == UPIO_AU)
> +		offset = au_io_out_map[offset];
> +#endif
> +
>  	offset <<= up->port.regshift;
>  
>  	switch (up->port.iotype) {
> @@ -290,6 +332,12 @@ serial_out(struct uart_8250_port *up, in
>  		writel(value, up->port.membase + offset);
>  		break;
>  
> +#ifdef CONFIG_SERIAL_8250_AU1X00
> +	case UPIO_AU:
> +		__raw_writel(value, up->port.membase + offset);
> +		break;
> +#endif
> +
>  	default:
>  		outb(value, up->port.iobase + offset);
>  	}
> @@ -910,6 +958,15 @@ static void autoconfig(struct uart_8250_
>  		}
>  	}
>  #endif
> +
> +#ifdef CONFIG_SERIAL_8250_AU1X00
> +	/* if access method is AU, it is a AU */
> +	if (up->port.type == PORT_16550A && up->port.iotype == UPIO_AU) {
> +		up->port.type = PORT_AU1X00;

I don't really see the need for a new port type - it's a quirky
16550A with a silly register layout.

> +		up->capabilities |= UART_CAP_NOMSR;	/* to stop whine */

Since this is for a hardware quirk, this should be UART_BUG_xxx not
UART_CAP_xxx - it's not a capability as such.

> +	}
> +#endif
> +
>  	serial_outp(up, UART_LCR, save_lcr);
>  
>  	if (up->capabilities != uart_config[up->port.type].flags) {
> @@ -1057,6 +1114,10 @@ static void serial8250_enable_ms(struct 
>  {
>  	struct uart_8250_port *up = (struct uart_8250_port *)port;
>  
> +	/* no MSR capabilities */
> +	if (up->capabilities & UART_CAP_NOMSR)

ditto.

> +		return;
> +
>  	up->ier |= UART_IER_MSI;
>  	serial_out(up, UART_IER, up->ier);
>  }
> @@ -1774,7 +1835,7 @@ serial8250_set_termios(struct uart_port 
>  	 * CTS flow control flag and modem status interrupts
>  	 */
>  	up->ier &= ~UART_IER_MSI;
> -	if (UART_ENABLE_MS(&up->port, termios->c_cflag))
> +	if (!(up->capabilities & UART_CAP_NOMSR) && UART_ENABLE_MS(&up->port, termios->c_cflag))

ditto.

>  		up->ier |= UART_IER_MSI;
>  	if (up->capabilities & UART_CAP_UUE)
>  		up->ier |= UART_IER_UUE | UART_IER_RTOIE;
> diff --git a/drivers/serial/8250.h b/drivers/serial/8250.h
> --- a/drivers/serial/8250.h
> +++ b/drivers/serial/8250.h
> @@ -46,6 +46,7 @@ struct serial8250_config {
>  #define UART_CAP_SLEEP	(1 << 10)	/* UART has IER sleep */
>  #define UART_CAP_AFE	(1 << 11)	/* MCR-based hw flow control */
>  #define UART_CAP_UUE	(1 << 12)	/* UART needs IER bit 6 set (Xscale) */
> +#define UART_CAP_NOMSR	(1 << 13)	/* UART has no modem status bits (Au1x00) */

ditto.

>  
>  #define UART_BUG_QUOT	(1 << 0)	/* UART has buggy quot LSB */
>  #define UART_BUG_TXEN	(1 << 1)	/* UART has buggy TX IIR status */
> diff --git a/drivers/serial/8250_au1x00.c b/drivers/serial/8250_au1x00.c
> new file mode 100644
> --- /dev/null
> +++ b/drivers/serial/8250_au1x00.c
> @@ -0,0 +1,95 @@
> +/*
> + * Serial Device Initialisation for Au1x00
> + *
> + * (C) Copyright Embedded Alley Solutions, Inc 2005
> + * Author: Pantelis Antoniou <pantelis@embeddedalley.com>
> + *
> + * 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.
> + */
> +
> +#include <linux/errno.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/ioport.h>
> +#include <linux/module.h>
> +#include <linux/serial_core.h>
> +#include <linux/signal.h>
> +#include <linux/slab.h>
> +#include <linux/types.h>
> +
> +#include <linux/serial_8250.h>
> +
> +#include <asm/mach-au1x00/au1000.h>
> +
> +#include "8250.h"
> +
> +#define PORT(_base, _irq)				\
> +	{						\
> +		.iobase		= _base,		\
> +		.membase	= (void __iomem *)_base,\
> +		.mapbase	= _base,		\
> +		.irq		= _irq,			\
> +		.uartclk	= 0,	/* filled */	\
> +		.regshift	= 2,			\
> +		.iotype		= UPIO_AU,		\
> +		.flags		= UPF_SKIP_TEST | 	\
> +				  UPF_IOREMAP,		\
> +	}
> +
> +static struct plat_serial8250_port au1x00_data[] = {
> +#if defined(CONFIG_SOC_AU1000)
> +	PORT(UART0_ADDR, AU1000_UART0_INT),
> +	PORT(UART1_ADDR, AU1000_UART1_INT),
> +	PORT(UART2_ADDR, AU1000_UART2_INT),
> +	PORT(UART3_ADDR, AU1000_UART3_INT),
> +#elif defined(CONFIG_SOC_AU1500)
> +	PORT(UART0_ADDR, AU1500_UART0_INT),
> +	PORT(UART3_ADDR, AU1500_UART3_INT),
> +#elif defined(CONFIG_SOC_AU1100)
> +	PORT(UART0_ADDR, AU1100_UART0_INT),
> +	PORT(UART1_ADDR, AU1100_UART1_INT),
> +	PORT(UART2_ADDR, AU1100_UART2_INT),
> +	PORT(UART3_ADDR, AU1100_UART3_INT),
> +#elif defined(CONFIG_SOC_AU1550)
> +	PORT(UART0_ADDR, AU1550_UART0_INT),
> +	PORT(UART1_ADDR, AU1550_UART1_INT),
> +	PORT(UART2_ADDR, AU1550_UART2_INT),
> +	PORT(UART3_ADDR, AU1550_UART3_INT),
> +#elif defined(CONFIG_SOC_AU1200)
> +	PORT(UART0_ADDR, AU1200_UART0_INT),
> +	PORT(UART1_ADDR, AU1200_UART1_INT),
> +#endif
> +	{ },
> +};
> +
> +static struct platform_device au1x00_device = {
> +	.name			= "serial8250",
> +	.id			= PLAT8250_DEV_AU1X00,
> +	.dev			= {
> +		.platform_data	= au1x00_data,
> +	},
> +};
> +
> +static int __init au1x00_init(void)
> +{
> +	int i;
> +	unsigned int uartclk;
> +
> +	/* get uart clock */
> +	uartclk = get_au1x00_uart_baud_base() * 16;
> +
> +	/* fill up uartclk */
> +	for (i = 0; au1x00_data[i].flags ; i++)
> +		au1x00_data[i].uartclk = uartclk;
> +
> +	return platform_device_register(&au1x00_device);

This seems to be capable of being a modular, yet it's registering a
static platform device structure, which will cause an oops if this
module is force-unloaded.  Should it always be built in?

> +}
> +
> +module_init(au1x00_init);
> +
> +MODULE_AUTHOR("Pantelis Antoniou <pantelis@embeddedalley.com>");
> +MODULE_DESCRIPTION("8250 serial probe module for Au1x000 cards");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
> --- a/drivers/serial/Kconfig
> +++ b/drivers/serial/Kconfig
> @@ -207,6 +207,14 @@ config SERIAL_8250_ACORN
>  	  system, say Y to this option.  The driver can handle 1, 2, or 3 port
>  	  cards.  If unsure, say N.
>  
> +config SERIAL_8250_AU1X00
> +	tristate "AU1X00 serial port support"
> +	depends on SOC_AU1X00 && SERIAL_8250
> +	help
> +	  If you have an Au1x00 board and want to use the serial port, say Y
> +	  to this option.  The driver can handle 1 or 2 serial ports.
> +	  If unsure, say N.
> +
>  comment "Non-8250 serial port support"
>  
>  config SERIAL_AMBA_PL010
> diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
> --- a/drivers/serial/Makefile
> +++ b/drivers/serial/Makefile
> @@ -22,6 +22,7 @@ obj-$(CONFIG_SERIAL_8250_ACCENT) += 8250
>  obj-$(CONFIG_SERIAL_8250_BOCA) += 8250_boca.o
>  obj-$(CONFIG_SERIAL_8250_HUB6) += 8250_hub6.o
>  obj-$(CONFIG_SERIAL_8250_MCA) += 8250_mca.o
> +obj-$(CONFIG_SERIAL_8250_AU1X00) += 8250_au1x00.o
>  obj-$(CONFIG_SERIAL_AMBA_PL010) += amba-pl010.o
>  obj-$(CONFIG_SERIAL_AMBA_PL011) += amba-pl011.o
>  obj-$(CONFIG_SERIAL_CLPS711X) += clps711x.o
> diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
> --- a/drivers/serial/serial_core.c
> +++ b/drivers/serial/serial_core.c
> @@ -1960,6 +1960,7 @@ uart_report_port(struct uart_driver *drv
>  		break;
>  	case UPIO_MEM:
>  	case UPIO_MEM32:
> +	case UPIO_AU:
>  		snprintf(address, sizeof(address),
>  			 "MMIO 0x%lx", port->mapbase);
>  		break;
> diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
> --- a/include/linux/serial_8250.h
> +++ b/include/linux/serial_8250.h
> @@ -42,6 +42,7 @@ enum {
>  	PLAT8250_DEV_BOCA,
>  	PLAT8250_DEV_HUB6,
>  	PLAT8250_DEV_MCA,
> +	PLAT8250_DEV_AU1X00,
>  };
>  
>  /*
> diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
> --- a/include/linux/serial_core.h
> +++ b/include/linux/serial_core.h
> @@ -39,7 +39,8 @@
>  #define PORT_RSA	13
>  #define PORT_NS16550A	14
>  #define PORT_XSCALE	15
> -#define PORT_MAX_8250	15	/* max port ID */
> +#define PORT_AU1X00	16
> +#define PORT_MAX_8250	16	/* max port ID */
>  
>  /*
>   * ARM specific type numbers.  These are not currently guaranteed
> @@ -209,6 +210,7 @@ struct uart_port {
>  #define UPIO_HUB6		(1)
>  #define UPIO_MEM		(2)
>  #define UPIO_MEM32		(3)
> +#define UPIO_AU			(4)			/* Au1x00 type IO */
>  
>  	unsigned int		read_status_mask;	/* driver specific */
>  	unsigned int		ignore_status_mask;	/* driver specific */


-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 Serial core