[PATCH] serial driver PMC MSP71xx, kernel linux-mips.git master

[Marc St-Jean <stjeanma@pmc-sierra.com>]

Fifth attempt at the serial driver patch for the PMC-Sierra MSP71xx device.

There are three different fixes:
1. Fix for DesignWare THRE errata
- Dropped our fix since the "8250-uart-backup-timer.patch" in the "mm"
tree also fixes it. This patch needs to be applied on top of "mm" patch.

2. Fix for Busy Detect on LCR write
- Minor formatting changes.

3. Workaround for interrupt/data concurrency issue
- No changes since last patch.

Sending with /bin/mail, how's that for bare iron...

Thanks,
Marc

Signed-off-by: Marc St-Jean <Marc_St-Jean@pmc-sierra.com>

diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 3d91bfc..3362782 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -308,6 +308,7 @@ static unsigned int serial_in(struct uar
 		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 @@ #endif
 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 @@ #endif
 			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) && in_irq())
+			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 *u
 #ifdef CONFIG_SERIAL_8250_AU1X00
 	case UPIO_AU:
 #endif
+	case UPIO_DWAPB:
 		serial_out(up, offset, value);
 		(void)serial_in(up, UART_LCR); /* safe, no side-effects */
 		break;
@@ -1383,6 +1399,19 @@ static irqreturn_t serial8250_interrupt(
 			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;
 
@@ -2085,6 +2114,7 @@ static int serial8250_request_std_resour
 	case UPIO_TSI:
 	case UPIO_MEM32:
 	case UPIO_MEM:
+	case UPIO_DWAPB:
 		if (!up->port.mapbase)
 			break;
 
@@ -2122,6 +2152,7 @@ static void serial8250_release_std_resou
 	case UPIO_TSI:
 	case UPIO_MEM32:
 	case UPIO_MEM:
+	case UPIO_DWAPB:
 		if (!up->port.mapbase)
 			break;
 
@@ -2454,8 +2485,8 @@ int __init serial8250_start_console(stru
 
 	add_preferred_console("ttyS", line, options);
 	printk("Adding console on ttyS%d at %s 0x%lx (options '%s')\n",
-		line, port->iotype == UPIO_MEM ? "MMIO" : "I/O port",
-		port->iotype == UPIO_MEM ? (unsigned long) port->mapbase :
+		line, port->iotype >= UPIO_MEM ? "MMIO" : "I/O port",
+		port->iotype >= UPIO_MEM ? (unsigned long) port->mapbase :
 		    (unsigned long) port->iobase, options);
 	if (!(serial8250_console.flags & CON_ENABLED)) {
 		serial8250_console.flags &= ~CON_PRINTBUFFER;
diff --git a/drivers/serial/8250.h b/drivers/serial/8250.h
diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index f84982e..f5b6036 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -2057,6 +2057,7 @@ uart_report_port(struct uart_driver *drv
 	case UPIO_MEM32:
 	case UPIO_AU:
 	case UPIO_TSI:
+	case UPIO_DWAPB:
 		snprintf(address, sizeof(address),
 			 "MMIO 0x%lx", port->mapbase);
 		break;
@@ -2401,6 +2402,7 @@ int uart_match_port(struct uart_port *po
 	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 cf23813..8cdd326 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -230,6 +230,7 @@ #define UPIO_MEM		(2)
 #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 @@ #define UPF_USR_MASK		((__force upf_t) (
 	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 3c8a6aa..1c5ed7d 100644
--- a/include/linux/serial_reg.h
+++ b/include/linux/serial_reg.h
@@ -38,6 +38,8 @@ #define UART_IIR_THRI		0x02 /* Transmitt
 #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 */