kernel-ark/arch/mips/cavium-octeon/serial.c
David Daney 4b8bca7028 MIPS: Octeon: Use I/O clock rate for calculations.
The I2C and UARTS are clocked by the I/O clock, use its rate for these
devices.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Patchwork: http://patchwork.linux-mips.org/patch/1670/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2010-10-29 19:08:41 +01:00

138 lines
3.6 KiB
C

/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2004-2007 Cavium Networks
*/
#include <linux/console.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/serial.h>
#include <linux/serial_8250.h>
#include <linux/serial_reg.h>
#include <linux/tty.h>
#include <linux/irq.h>
#include <asm/time.h>
#include <asm/octeon/octeon.h>
#define DEBUG_UART 1
unsigned int octeon_serial_in(struct uart_port *up, int offset)
{
int rv = cvmx_read_csr((uint64_t)(up->membase + (offset << 3)));
if (offset == UART_IIR && (rv & 0xf) == 7) {
/* Busy interrupt, read the USR (39) and try again. */
cvmx_read_csr((uint64_t)(up->membase + (39 << 3)));
rv = cvmx_read_csr((uint64_t)(up->membase + (offset << 3)));
}
return rv;
}
void octeon_serial_out(struct uart_port *up, int offset, int value)
{
/*
* If bits 6 or 7 of the OCTEON UART's LCR are set, it quits
* working.
*/
if (offset == UART_LCR)
value &= 0x9f;
cvmx_write_csr((uint64_t)(up->membase + (offset << 3)), (u8)value);
}
/*
* Allocated in .bss, so it is all zeroed.
*/
#define OCTEON_MAX_UARTS 3
static struct plat_serial8250_port octeon_uart8250_data[OCTEON_MAX_UARTS + 1];
static struct platform_device octeon_uart8250_device = {
.name = "serial8250",
.id = PLAT8250_DEV_PLATFORM,
.dev = {
.platform_data = octeon_uart8250_data,
},
};
static void __init octeon_uart_set_common(struct plat_serial8250_port *p)
{
p->flags = ASYNC_SKIP_TEST | UPF_SHARE_IRQ | UPF_FIXED_TYPE;
p->type = PORT_OCTEON;
p->iotype = UPIO_MEM;
p->regshift = 3; /* I/O addresses are every 8 bytes */
if (octeon_is_simulation())
/* Make simulator output fast*/
p->uartclk = 115200 * 16;
else
p->uartclk = octeon_get_io_clock_rate();
p->serial_in = octeon_serial_in;
p->serial_out = octeon_serial_out;
}
static int __init octeon_serial_init(void)
{
int enable_uart0;
int enable_uart1;
int enable_uart2;
struct plat_serial8250_port *p;
#ifdef CONFIG_CAVIUM_OCTEON_2ND_KERNEL
/*
* If we are configured to run as the second of two kernels,
* disable uart0 and enable uart1. Uart0 is owned by the first
* kernel
*/
enable_uart0 = 0;
enable_uart1 = 1;
#else
/*
* We are configured for the first kernel. We'll enable uart0
* if the bootloader told us to use 0, otherwise will enable
* uart 1.
*/
enable_uart0 = (octeon_get_boot_uart() == 0);
enable_uart1 = (octeon_get_boot_uart() == 1);
#ifdef CONFIG_KGDB
enable_uart1 = 1;
#endif
#endif
/* Right now CN52XX is the only chip with a third uart */
enable_uart2 = OCTEON_IS_MODEL(OCTEON_CN52XX);
p = octeon_uart8250_data;
if (enable_uart0) {
/* Add a ttyS device for hardware uart 0 */
octeon_uart_set_common(p);
p->membase = (void *) CVMX_MIO_UARTX_RBR(0);
p->mapbase = CVMX_MIO_UARTX_RBR(0) & ((1ull << 49) - 1);
p->irq = OCTEON_IRQ_UART0;
p++;
}
if (enable_uart1) {
/* Add a ttyS device for hardware uart 1 */
octeon_uart_set_common(p);
p->membase = (void *) CVMX_MIO_UARTX_RBR(1);
p->mapbase = CVMX_MIO_UARTX_RBR(1) & ((1ull << 49) - 1);
p->irq = OCTEON_IRQ_UART1;
p++;
}
if (enable_uart2) {
/* Add a ttyS device for hardware uart 2 */
octeon_uart_set_common(p);
p->membase = (void *) CVMX_MIO_UART2_RBR;
p->mapbase = CVMX_MIO_UART2_RBR & ((1ull << 49) - 1);
p->irq = OCTEON_IRQ_UART2;
p++;
}
BUG_ON(p > &octeon_uart8250_data[OCTEON_MAX_UARTS]);
return platform_device_register(&octeon_uart8250_device);
}
device_initcall(octeon_serial_init);