[PATCH 23/26] Serial: UART driver changes for Cavium OCTEON.

David Daney
2008-11-18T22:24:22Z

Cavium UART implementation won't work with the standard 8250 driver
as-is. Define a new uart_config (PORT_OCTEON) and use it to enable
special handling required by the OCTEON's serial port. Two new bug
types are defined.

Signed-off-by: Tomaso Paoletti <tpaoletti@caviumnetworks.com>
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
---
drivers/serial/8250.c | 16 +++++++++++++++-
drivers/serial/8250.h | 2 ++
include/linux/serial_core.h | 3 ++-
include/linux/serial_reg.h | 6 ++++++
4 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 4a8796f..e80b67e 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -279,6 +279,14 @@ static const struct serial8250_config uart_config[] = {
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
.flags = UART_CAP_FIFO,
},
+ [PORT_OCTEON] = {
+ .name = "OCTEON",
+ .fifo_size = 64,
+ .tx_loadsz = 64,
+ .bugs = UART_BUG_TIMEOUT | UART_BUG_OCTEON_IIR,
+ .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+ .flags = UART_CAP_FIFO,
+ },
};

#if defined (CONFIG_SERIAL_8250_AU1X00)
@@ -1554,6 +1562,12 @@ static irqreturn_t serial8250_interrupt(int irq, void *dev_id)
up = list_entry(l, struct uart_8250_port, list);

iir = serial_in(up, UART_IIR);
+ if ((up->bugs & UART_BUG_OCTEON_IIR) && (iir & 0xf) == 7) {
+ /* Busy interrupt */
+ serial_in(up, UART_OCTEON_USR);
+ iir = serial_in(up, UART_IIR);
+ }
+
if (!(iir & UART_IIR_NO_INT)) {
serial8250_handle_port(up);

@@ -1714,7 +1728,7 @@ static void serial8250_timeout(unsigned long data)
unsigned int iir;

iir = serial_in(up, UART_IIR);
- if (!(iir & UART_IIR_NO_INT))
+ if (!(iir & UART_IIR_NO_INT) || (up->bugs & UART_BUG_TIMEOUT))
serial8250_handle_port(up);
mod_timer(&up->timer, jiffies + poll_timeout(up->port.timeout));
}
diff --git a/drivers/serial/8250.h b/drivers/serial/8250.h
index c9b3002..56b3cb7 100644
--- a/drivers/serial/8250.h
+++ b/drivers/serial/8250.h
@@ -49,6 +49,8 @@ struct serial8250_config {
#define UART_BUG_TXEN (1 << 1) /* UART has buggy TX IIR status */
#define UART_BUG_NOMSR (1 << 2) /* UART has buggy MSR status bits (Au1x00) */
#define UART_BUG_THRE (1 << 3) /* UART has buggy THRE reassertion */
+#define UART_BUG_TIMEOUT (1 << 4) /* UART should always handle timeout */
+#define UART_BUG_OCTEON_IIR (1 << 5) /* UART OCTEON IIR workaround */

#define PROBE_RSA (1 << 0)
#define PROBE_ANY (~0)
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 4a72a7b..e79409f 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -40,7 +40,8 @@
#define PORT_NS16550A 14
#define PORT_XSCALE 15
#define PORT_RM9000 16 /* PMC-Sierra RM9xxx internal UART */
-#define PORT_MAX_8250 16 /* max port ID */
+#define PORT_OCTEON 17 /* Cavium OCTEON internal UART */
+#define PORT_MAX_8250 17 /* max port ID */

/*
* ARM specific type numbers. These are not currently guaranteed
diff --git a/include/linux/serial_reg.h b/include/linux/serial_reg.h
index 96c0d93..a96bd50 100644
--- a/include/linux/serial_reg.h
+++ b/include/linux/serial_reg.h
@@ -324,5 +324,11 @@
#define UART_OMAP_SYSC 0x15 /* System configuration register */
#define UART_OMAP_SYSS 0x16 /* System status register */

+/*
+ * Extra serial register definitions for the internal UARTs in Cavium
+ * Networks OCTEON processors.
+ */
+#define UART_OCTEON_USR 0x27 /* UART Status Register */
+
#endif /* _LINUX_SERIAL_REG_H */

--
1.5.6.5