From beab697ab4b2962e3d741b476abe443baad0933d Mon Sep 17 00:00:00 2001 From: Marc St-Jean Date: Sun, 6 May 2007 14:48:45 -0700 Subject: [PATCH] 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 ++++++++++++++++++++++ drivers/serial/8250.c | 31 ++++ drivers/serial/serial_core.c | 2 + include/linux/serial_core.h | 2 + include/linux/serial_reg.h | 2 + 5 files changed, 202 insertions(+) create mode 100644 arch/mips/pmc-sierra/msp71xx/msp_serial.c 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 0000000000..c41b53faa8 --- /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"); +} diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c index 90621c3312..194362d9f5 100644 --- a/drivers/serial/8250.c +++ b/drivers/serial/8250.c @@ -308,6 +308,7 @@ static unsigned int serial_in(struct uart_8250_port *up, int offset) return inb(up->port.iobase + 1); case UPIO_MEM: + case UPIO_DWAPB: return readb(up->port.membase + offset); case UPIO_MEM32: @@ -333,6 +334,8 @@ static unsigned int serial_in(struct uart_8250_port *up, int offset) static void serial_out(struct uart_8250_port *up, int offset, int value) { + /* Save the offset before it's remapped */ + int save_offset = offset; offset = map_8250_out_reg(up, offset) << up->port.regshift; switch (up->port.iotype) { @@ -359,6 +362,18 @@ serial_out(struct uart_8250_port *up, int offset, int value) writeb(value, up->port.membase + offset); break; + case UPIO_DWAPB: + /* Save the LCR value so it can be re-written when a + * Busy Detect interrupt occurs. */ + if (save_offset == UART_LCR) + up->lcr = value; + writeb(value, up->port.membase + offset); + /* Read the IER to ensure any interrupt is cleared before + * returning from ISR. */ + if (save_offset == UART_TX || save_offset == UART_IER) + value = serial_in(up, UART_IER); + break; + default: outb(value, up->port.iobase + offset); } @@ -373,6 +388,7 @@ serial_out_sync(struct uart_8250_port *up, int offset, int value) #ifdef CONFIG_SERIAL_8250_AU1X00 case UPIO_AU: #endif + case UPIO_DWAPB: serial_out(up, offset, value); serial_in(up, UART_LCR); /* safe, no side-effects */ break; @@ -1388,6 +1404,19 @@ static irqreturn_t serial8250_interrupt(int irq, void *dev_id) handled = 1; + end = NULL; + } else if (up->port.iotype == UPIO_DWAPB && + (iir & UART_IIR_BUSY) == UART_IIR_BUSY) { + /* The DesignWare APB UART has an Busy Detect (0x07) + * interrupt meaning an LCR write attempt occured while the + * UART was busy. The interrupt must be cleared by reading + * the UART status register (USR) and the LCR re-written. */ + unsigned int status; + status = *(volatile u32 *)up->port.private_data; + serial_out(up, UART_LCR, up->lcr); + + handled = 1; + end = NULL; } else if (end == NULL) end = l; @@ -2090,6 +2119,7 @@ static int serial8250_request_std_resource(struct uart_8250_port *up) case UPIO_TSI: case UPIO_MEM32: case UPIO_MEM: + case UPIO_DWAPB: if (!up->port.mapbase) break; @@ -2127,6 +2157,7 @@ static void serial8250_release_std_resource(struct uart_8250_port *up) case UPIO_TSI: case UPIO_MEM32: case UPIO_MEM: + case UPIO_DWAPB: if (!up->port.mapbase) break; diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c index 0422c0f1f8..a677133ab2 100644 --- a/drivers/serial/serial_core.c +++ b/drivers/serial/serial_core.c @@ -2064,6 +2064,7 @@ uart_report_port(struct uart_driver *drv, struct uart_port *port) case UPIO_MEM32: case UPIO_AU: case UPIO_TSI: + case UPIO_DWAPB: snprintf(address, sizeof(address), "MMIO 0x%lx", port->mapbase); break; @@ -2409,6 +2410,7 @@ int uart_match_port(struct uart_port *port1, struct uart_port *port2) case UPIO_MEM32: case UPIO_AU: case UPIO_TSI: + case UPIO_DWAPB: return (port1->mapbase == port2->mapbase); } return 0; diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 586aaba917..8b5592e6ac 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -230,6 +230,7 @@ struct uart_port { #define UPIO_MEM32 (3) #define UPIO_AU (4) /* Au1x00 type IO */ #define UPIO_TSI (5) /* Tsi108/109 type IO */ +#define UPIO_DWAPB (6) /* DesignWare APB UART */ unsigned int read_status_mask; /* driver specific */ unsigned int ignore_status_mask; /* driver specific */ @@ -276,6 +277,7 @@ struct uart_port { struct device *dev; /* parent device */ unsigned char hub6; /* this should be in the 8250 driver */ unsigned char unused[3]; + void *private_data; /* generic platform data pointer */ }; /* diff --git a/include/linux/serial_reg.h b/include/linux/serial_reg.h index 3c8a6aa774..1c5ed7d92b 100644 --- a/include/linux/serial_reg.h +++ b/include/linux/serial_reg.h @@ -38,6 +38,8 @@ #define UART_IIR_RDI 0x04 /* Receiver data interrupt */ #define UART_IIR_RLSI 0x06 /* Receiver line status interrupt */ +#define UART_IIR_BUSY 0x07 /* DesignWare APB Busy Detect */ + #define UART_FCR 2 /* Out: FIFO Control Register */ #define UART_FCR_ENABLE_FIFO 0x01 /* Enable the FIFO */ #define UART_FCR_CLEAR_RCVR 0x02 /* Clear the RCVR FIFO */ -- 2.39.5