[PATCH 08/12] 8250: add support for ASIX devices with a FIFO bug

Alan Cox
2012-06-22T15:28:34Z

From: Alan Cox <alan@linux.intel.com>

Information and a different patch provided by <donald@asix.com.tw>. We do
it a little differently to keep the modularity and to avoid playing with
RLSI.

We add a new uart bug for the parity flaw and set it in the pci matches.
If parity check is enabled then we drop the FIFO trigger to 1 as per the
Asix reference code.

Signed-off-by: Alan Cox <alan@linux.intel.com>
---

drivers/tty/serial/8250/8250.c | 8 ++++++--
drivers/tty/serial/8250/8250.h | 1 +
drivers/tty/serial/8250/8250_pci.c | 24 +++++++++++++++++++++---
3 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/drivers/tty/serial/8250/8250.c b/drivers/tty/serial/8250/8250.c
index 779d791..641768c 100644
--- a/drivers/tty/serial/8250/8250.c
+++ b/drivers/tty/serial/8250/8250.c
@@ -2194,6 +2194,7 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
unsigned char cval, fcr = 0;
unsigned long flags;
unsigned int baud, quot;
+ int fifo_bug = 0;

switch (termios->c_cflag & CSIZE) {
case CS5:
@@ -2213,8 +2214,11 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,

if (termios->c_cflag & CSTOPB)
cval |= UART_LCR_STOP;
- if (termios->c_cflag & PARENB)
+ if (termios->c_cflag & PARENB) {
cval |= UART_LCR_PARITY;
+ if (up->bugs & UART_BUG_PARITY)
+ fifo_bug = 1;
+ }
if (!(termios->c_cflag & PARODD))
cval |= UART_LCR_EPAR;
#ifdef CMSPAR
@@ -2238,7 +2242,7 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,

if (up->capabilities & UART_CAP_FIFO && port->fifosize > 1) {
fcr = uart_config[port->type].fcr;
- if (baud < 2400) {
+ if (baud < 2400 || fifo_bug) {
fcr &= ~UART_FCR_TRIGGER_MASK;
fcr |= UART_FCR_TRIGGER_1;
}
diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
index f9719d1..c335b2b 100644
--- a/drivers/tty/serial/8250/8250.h
+++ b/drivers/tty/serial/8250/8250.h
@@ -78,6 +78,7 @@ 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_PARITY (1 << 4) /* UART mishandles parity if FIFO enabled */

#define PROBE_RSA (1 << 0)
#define PROBE_ANY (~0)
diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index 7269b15..8f137d8 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -1032,8 +1032,15 @@ static int pci_oxsemi_tornado_init(struct pci_dev *dev)
return number_uarts;
}

-static int
-pci_default_setup(struct serial_private *priv,
+static int pci_asix_setup(struct serial_private *priv,
+ const struct pciserial_board *board,
+ struct uart_8250_port *port, int idx)
+{
+ port->bugs |= UART_BUG_PARITY;
+ return pci_default_setup(priv, board, port, idx);
+}
+
+static int pci_default_setup(struct serial_private *priv,
const struct pciserial_board *board,
struct uart_8250_port *port, int idx)
{
@@ -1187,6 +1194,7 @@ pci_xr17c154_setup(struct serial_private *priv,
#define PCIE_DEVICE_ID_NEO_2_OX_IBM 0x00F6
#define PCI_DEVICE_ID_PLX_CRONYX_OMEGA 0xc001
#define PCI_DEVICE_ID_INTEL_PATSBURG_KT 0x1d3d
+#define PCI_VENDOR_ID_ASIX 0x9710

/* Unknown vendors/cards - this should not be in linux/pci_ids.h */
#define PCI_SUBDEVICE_ID_UNKNOWN_0x1584 0x1584
@@ -1726,7 +1734,17 @@ static struct pci_serial_quirk pci_serial_quirks[] __refdata = {
.subvendor = PCI_ANY_ID,
.subdevice = PCI_ANY_ID,
.setup = pci_omegapci_setup,
- },
+ },
+ /*
+ * ASIX devices with FIFO bug
+ */
+ {
+ .vendor = PCI_VENDOR_ID_ASIX,
+ .device = PCI_ANY_ID,
+ .subvendor = PCI_ANY_ID,
+ .subdevice = PCI_ANY_ID,
+ .setup = pci_asix_setup,
+ },
/*
* Default "match everything" terminator entry
*/