From beab697ab4b2962e3d741b476abe443baad0933d Mon Sep 17 00:00:00 2001 From: Marc St-Jean Date: Sun, 6 May 2007 14:48:45 -0700 Subject: serial driver PMC MSP71xx Serial driver patch for the PMC-Sierra MSP71xx devices. There are three different fixes: 1 Fix for DesignWare APB THRE errata: In brief, this is a non-standard 16550 in that the THRE interrupt will not re-assert itself simply by disabling and re-enabling the THRI bit in the IER, it is only re-enabled if a character is actually sent out. It appears that the "8250-uart-backup-timer.patch" in the "mm" tree also fixes it so we have dropped our initial workaround. This patch now needs to be applied on top of that "mm" patch. 2 Fix for Busy Detect on LCR write: The DesignWare APB UART has a feature which causes a new Busy Detect interrupt to be generated if it's busy when the LCR is written. This fix saves the value of the LCR and rewrites it after clearing the interrupt. 3 Workaround for interrupt/data concurrency issue: The SoC needs to ensure that writes that can cause interrupts to be cleared reach the UART before returning from the ISR. This fix reads a non-destructive register on the UART so the read transaction completion ensures the previously queued write transaction has also completed. Signed-off-by: Marc St-Jean Cc: Russell King Cc: Ralf Baechle Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/mips/pmc-sierra/msp71xx/msp_serial.c | 165 ++++++++++++++++++++++++++++++ 1 file changed, 165 insertions(+) create mode 100644 arch/mips/pmc-sierra/msp71xx/msp_serial.c (limited to 'arch/mips/pmc-sierra') diff --git a/arch/mips/pmc-sierra/msp71xx/msp_serial.c b/arch/mips/pmc-sierra/msp71xx/msp_serial.c new file mode 100644 index 00000000000..c41b53faa8f --- /dev/null +++ b/arch/mips/pmc-sierra/msp71xx/msp_serial.c @@ -0,0 +1,165 @@ +/* + * The setup file for serial related hardware on PMC-Sierra MSP processors. + * + * Copyright 2005 PMC-Sierra, Inc. + * + * 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 SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN + * NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF + * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON + * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * 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., + * 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#include +#include +#include + +#include +#include +#include +#include + +#include +#include +#include + +#ifdef CONFIG_KGDB +/* + * kgdb uses serial port 1 so the console can remain on port 0. + * To use port 0 change the definition to read as follows: + * #define DEBUG_PORT_BASE KSEG1ADDR(MSP_UART0_BASE) + */ +#define DEBUG_PORT_BASE KSEG1ADDR(MSP_UART1_BASE) + +int putDebugChar(char c) +{ + volatile uint32_t *uart = (volatile uint32_t *)DEBUG_PORT_BASE; + uint32_t val = (uint32_t)c; + + local_irq_disable(); + while( !(uart[5] & 0x20) ); /* Wait for TXRDY */ + uart[0] = val; + while( !(uart[5] & 0x20) ); /* Wait for TXRDY */ + local_irq_enable(); + + return 1; +} + +char getDebugChar(void) +{ + volatile uint32_t *uart = (volatile uint32_t *)DEBUG_PORT_BASE; + uint32_t val; + + while( !(uart[5] & 0x01) ); /* Wait for RXRDY */ + val = uart[0]; + + return (char)val; +} + +void initDebugPort(unsigned int uartclk, unsigned int baudrate) +{ + unsigned int baud_divisor = (uartclk + 8 * baudrate)/(16 * baudrate); + + /* Enable FIFOs */ + writeb(UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR | + UART_FCR_CLEAR_XMIT | UART_FCR_TRIGGER_4, + (char *)DEBUG_PORT_BASE + (UART_FCR * 4)); + + /* Select brtc divisor */ + writeb(UART_LCR_DLAB, (char *)DEBUG_PORT_BASE + (UART_LCR * 4)); + + /* Store divisor lsb */ + writeb(baud_divisor, (char *)DEBUG_PORT_BASE + (UART_TX * 4)); + + /* Store divisor msb */ + writeb(baud_divisor >> 8, (char *)DEBUG_PORT_BASE + (UART_IER * 4)); + + /* Set 8N1 mode */ + writeb(UART_LCR_WLEN8, (char *)DEBUG_PORT_BASE + (UART_LCR * 4)); + + /* Disable flow control */ + writeb(0, (char *)DEBUG_PORT_BASE + (UART_MCR * 4)); + + /* Disable receive interrupt(!) */ + writeb(0, (char *)DEBUG_PORT_BASE + (UART_IER * 4)); +} +#endif + +void __init msp_serial_setup(void) +{ + char *s; + char *endp; + struct uart_port up; + unsigned int uartclk; + + memset(&up, 0, sizeof(up)); + + /* Check if clock was specified in environment */ + s = prom_getenv("uartfreqhz"); + if(!(s && *s && (uartclk = simple_strtoul(s, &endp, 10)) && *endp == 0)) + uartclk = MSP_BASE_BAUD; + ppfinit("UART clock set to %d\n", uartclk); + + /* Initialize first serial port */ + up.mapbase = MSP_UART0_BASE; + up.membase = ioremap_nocache(up.mapbase,MSP_UART_REG_LEN); + up.irq = MSP_INT_UART0; + up.uartclk = uartclk; + up.regshift = 2; + up.iotype = UPIO_DWAPB; /* UPIO_MEM like */ + up.flags = STD_COM_FLAGS; + up.type = PORT_16550A; + up.line = 0; + up.private_data = (void*)UART0_STATUS_REG; + if (early_serial_setup(&up)) + printk(KERN_ERR "Early serial init of port 0 failed\n"); + + /* Initialize the second serial port, if one exists */ + switch (mips_machtype) { + case MACH_MSP4200_EVAL: + case MACH_MSP4200_GW: + case MACH_MSP4200_FPGA: + case MACH_MSP7120_EVAL: + case MACH_MSP7120_GW: + case MACH_MSP7120_FPGA: + /* Enable UART1 on MSP4200 and MSP7120 */ + *GPIO_CFG2_REG = 0x00002299; + +#ifdef CONFIG_KGDB + /* Initialize UART1 for kgdb since PMON doesn't */ + if( DEBUG_PORT_BASE == KSEG1ADDR(MSP_UART1_BASE) ) { + if( mips_machtype == MACH_MSP4200_FPGA + || mips_machtype == MACH_MSP7120_FPGA ) + initDebugPort(uartclk,19200); + else + initDebugPort(uartclk,57600); + } +#endif + break; + + default: + return; /* No second serial port, good-bye. */ + } + + up.mapbase = MSP_UART1_BASE; + up.membase = ioremap_nocache(up.mapbase,MSP_UART_REG_LEN); + up.irq = MSP_INT_UART1; + up.line = 1; + up.private_data = (void*)UART1_STATUS_REG; + if (early_serial_setup(&up)) + printk(KERN_ERR "Early serial init of port 1 failed\n"); +} -- cgit v1.2.3