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[PATCH 27/29] Serial: UART driver changes for Cavium OCTEON.

To: linux-mips@linux-mips.org
Subject: [PATCH 27/29] Serial: UART driver changes for Cavium OCTEON.
From: David Daney <ddaney@caviumnetworks.com>
Date: Thu, 6 Nov 2008 12:57:05 -0800
Cc: linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, akpm@linux-foundation.org, David Daney <ddaney@caviumnetworks.com>, Tomaso Paoletti <tpaoletti@caviumnetworks.com>
In-reply-to: <491358F5.7040002@caviumnetworks.com>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <491358F5.7040002@caviumnetworks.com>
Sender: linux-mips-bounce@linux-mips.org
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 474ab89..f274e94 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 54e0dce..c6c7faa 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


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