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Message-ID: <4F7B53C9.4040509@fb.com>
Date: Tue, 3 Apr 2012 12:47:21 -0700
From: sudhakar <sudhakar@...com>
To: <linux-serial@...r.kernel.org>
CC: <alan@...ux.intel.com>, <gregkh@...uxfoundation.org>,
<dan.j.williams@...el.com>, <nhan.h.mai@...el.com>,
<linux-kernel@...r.kernel.org>
Subject: [PATCH 2/2] serial/8250_pci: Need to clear FIFOs for KT serial on
BI
From: Sudhakar Mamillapalli <sudhakar@...com>
When using SOL thru a KT serial device and Intel ME gets reset
the serial FIFOs need to be cleared for sane SOL output. On
a reset the device assertes BI, so using that as a cue FIFOs
are cleared. One other problem is that the serial registers
might temporarily go to 0 on reset for this device. So
instead of restoring IER register from read value in
poll_char and other functions we get the value from
uart_8250_port which should have the same value.
Signed-off-by: Sudhakar Mamillapalli <sudhakar@...com>
Acked-by: Dan Williams <dan.j.williams@...el.com>
Acked-by: Nhan H Mai <nhan.h.mai@...el.com>
---
drivers/tty/serial/8250/8250.c | 37 +++++++++++++++++++++++++++++++++--
drivers/tty/serial/8250/8250_pci.c | 3 +-
include/linux/serial_core.h | 3 +-
3 files changed, 38 insertions(+), 5 deletions(-)
diff --git a/drivers/tty/serial/8250/8250.c b/drivers/tty/serial/8250/8250.c
index 5fb0157..c61799e 100644
--- a/drivers/tty/serial/8250/8250.c
+++ b/drivers/tty/serial/8250/8250.c
@@ -282,6 +282,13 @@ static const struct serial8250_config uart_config[] = {
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
.flags = UART_CAP_FIFO | UART_CAP_AFE | UART_CAP_EFR,
},
+ [PORT_KT_SERIAL] = {
+ .name = "KTSERIAL",
+ .fifo_size = 16,
+ .tx_loadsz = 16,
+ .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+ .flags = UART_CAP_FIFO,
+ },
};
#if defined(CONFIG_MIPS_ALCHEMY)
@@ -1363,6 +1370,7 @@ serial8250_rx_chars(struct uart_8250_port *up, unsigned char lsr)
struct uart_port *port = &up->port;
struct tty_struct *tty = port->state->port.tty;
unsigned char ch;
+ unsigned char fcr;
int max_count = 256;
char flag;
@@ -1385,6 +1393,16 @@ serial8250_rx_chars(struct uart_8250_port *up, unsigned char lsr)
lsr |= up->lsr_saved_flags;
up->lsr_saved_flags = 0;
+ if ((up->port.type == PORT_KT_SERIAL) && (lsr & UART_LSR_BI)) {
+ /*
+ * For KT serial device if break interrupt then got
+ * to clear the fifos for sane SOL output.
+ */
+ serial8250_clear_fifos(up);
+ fcr = uart_config[up->port.type].fcr;
+ serial_port_out(port, UART_FCR, fcr);
+ }
+
if (unlikely(lsr & UART_LSR_BRK_ERROR_BITS)) {
/*
* For statistics only
@@ -1729,7 +1747,12 @@ static void serial8250_backup_timeout(unsigned long data)
* based handler.
*/
if (up->port.irq) {
- ier = serial_in(up, UART_IER);
+ /*
+ * Get the ier value from up->ier rather than reading the
+ * register, since some SOL uarts(for e.g. KT serial) it
+ * goes to 0 momentarily on BMC reset.
+ */
+ ier = up->ier;
serial_out(up, UART_IER, 0);
}
@@ -1896,8 +1919,12 @@ static void serial8250_put_poll_char(struct uart_port *port,
/*
* First save the IER then disable the interrupts
+ *
+ * Get the ier value from up->ier rather than reading the
+ * register, since some SOL uarts(for e.g. KT serial) it
+ * goes to 0 momentarily on BMC reset.
*/
- ier = serial_port_in(port, UART_IER);
+ ier = up->ier;
if (up->capabilities & UART_CAP_UUE)
serial_port_out(port, UART_IER, UART_IER_UUE);
else
@@ -2818,8 +2845,12 @@ serial8250_console_write(struct console *co, const char *s, unsigned int count)
/*
* First save the IER then disable the interrupts
+ *
+ * Get the ier value from up->ier rather than reading the
+ * register, since some SOL uarts(for e.g. KT serial) it
+ * goes to 0 momentarily on BMC reset.
*/
- ier = serial_port_in(port, UART_IER);
+ ier = up->ier;
if (up->capabilities & UART_CAP_UUE)
serial_port_out(port, UART_IER, UART_IER_UUE);
diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index 858dca8..1aebe63 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -1096,7 +1096,8 @@ static int kt_serial_setup(struct serial_private *priv,
const struct pciserial_board *board,
struct uart_port *port, int idx)
{
- port->flags |= UPF_BUG_THRE;
+ port->flags |= UPF_BUG_THRE | UPF_FIXED_TYPE;
+ port->type = PORT_KT_SERIAL;
return skip_tx_en_setup(priv, board, port, idx);
}
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 2db407a..efd7d0d 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -47,7 +47,8 @@
#define PORT_U6_16550A 19 /* ST-Ericsson U6xxx internal UART */
#define PORT_TEGRA 20 /* NVIDIA Tegra internal UART */
#define PORT_XR17D15X 21 /* Exar XR17D15x UART */
-#define PORT_MAX_8250 21 /* max port ID */
+#define PORT_KT_SERIAL 22 /* KT Serial SOL device */
+#define PORT_MAX_8250 22 /* max port ID */
/*
* ARM specific type numbers. These are not currently guaranteed
--
1.7.8.4
--
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