Revert "8250: add support for ASIX devices with a FIFO bug"

This reverts commit eb26dfe8aa7eeb5a5aa0b7574550125f8aa4c3b3.

Commit eb26dfe8aa7e ("8250: add support for ASIX devices with a FIFO
bug") merged on Jul 13, 2012 adds a quirk for PCI_VENDOR_ID_ASIX
(0x9710). But that ID is the same as PCI_VENDOR_ID_NETMOS defined in
1f8b061050c7 ("[PATCH] Netmos parallel/serial/combo support") merged
on Mar 28, 2005. In pci_serial_quirks array, the NetMos entry always
takes precedence over the ASIX entry even since it was initially
merged, code in that commit is always unreachable.

In my tests, adding the FIFO workaround to pci_netmos_init() makes no
difference, and the vendor driver also does not have such workaround.
Given that the code was never used for over a decade, it's safe to
revert it.

Also, the real PCI_VENDOR_ID_ASIX should be 0x125b, which is used on
their newer AX99100 PCIe serial controllers released on 2016. The FIFO
workaround should not be intended for these newer controllers, and it
was never implemented in vendor driver.

Fixes: eb26dfe8aa7e ("8250: add support for ASIX devices with a FIFO bug")
Cc: stable <stable@kernel.org>
Signed-off-by: Jiaqing Zhao <jiaqing.zhao@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230619155743.827859-1-jiaqing.zhao@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
index 471c6bc..1aa3e55 100644 (file)
--- a/drivers/tty/serial/8250/8250.h
+++ b/drivers/tty/serial/8250/8250.h
@@ -91,7 +91,6 @@ struct serial8250_config {
 #define UART_BUG_TXEN  BIT(1)  /* UART has buggy TX IIR status */
 #define UART_BUG_NOMSR BIT(2)  /* UART has buggy MSR status bits (Au1x00) */
 #define UART_BUG_THRE  BIT(3)  /* UART has buggy THRE reassertion */
-#define UART_BUG_PARITY        BIT(4)  /* UART mishandles parity if FIFO enabled */
 #define UART_BUG_TXRACE        BIT(5)  /* UART Tx fails to set remote DR */
 
 

diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index e80c4f6..d2d547b 100644 (file)
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -1232,14 +1232,6 @@ static int pci_oxsemi_tornado_setup(struct serial_private *priv,
        return pci_default_setup(priv, board, up, idx);
 }
 
-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);
-}
-
 #define QPCR_TEST_FOR1         0x3F
 #define QPCR_TEST_GET1         0x00
 #define QPCR_TEST_FOR2         0x40
@@ -1955,7 +1947,6 @@ pci_moxa_setup(struct serial_private *priv,
 #define PCI_DEVICE_ID_WCH_CH355_4S     0x7173
 #define PCI_VENDOR_ID_AGESTAR          0x5372
 #define PCI_DEVICE_ID_AGESTAR_9375     0x6872
-#define PCI_VENDOR_ID_ASIX             0x9710
 #define PCI_DEVICE_ID_BROADCOM_TRUMANAGE 0x160a
 #define PCI_DEVICE_ID_AMCC_ADDIDATA_APCI7800 0x818e
 
@@ -2600,16 +2591,6 @@ static struct pci_serial_quirk pci_serial_quirks[] = {
                .exit           = pci_wch_ch38x_exit,
                .setup          = pci_wch_ch38x_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,
-       },
        /*
         * Broadcom TruManage (NetXtreme)
         */

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index dfb51a8..16aeb14 100644 (file)
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -2632,11 +2632,8 @@ static unsigned char serial8250_compute_lcr(struct uart_8250_port *up,
 
        if (c_cflag & CSTOPB)
                cval |= UART_LCR_STOP;
-       if (c_cflag & PARENB) {
+       if (c_cflag & PARENB)
                cval |= UART_LCR_PARITY;
-               if (up->bugs & UART_BUG_PARITY)
-                       up->fifo_bug = true;
-       }
        if (!(c_cflag & PARODD))
                cval |= UART_LCR_EPAR;
        if (c_cflag & CMSPAR)
@@ -2799,8 +2796,7 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
        up->lcr = cval;                                 /* Save computed LCR */
 
        if (up->capabilities & UART_CAP_FIFO && port->fifosize > 1) {
-               /* NOTE: If fifo_bug is not set, a user can set RX_trigger. */
-               if ((baud < 2400 && !up->dma) || up->fifo_bug) {
+               if (baud < 2400 && !up->dma) {
                        up->fcr &= ~UART_FCR_TRIGGER_MASK;
                        up->fcr |= UART_FCR_TRIGGER_1;
                }
@@ -3131,8 +3127,7 @@ static int do_set_rxtrig(struct tty_port *port, unsigned char bytes)
        struct uart_8250_port *up = up_to_u8250p(uport);
        int rxtrig;
 
-       if (!(up->capabilities & UART_CAP_FIFO) || uport->fifosize <= 1 ||
-           up->fifo_bug)
+       if (!(up->capabilities & UART_CAP_FIFO) || uport->fifosize <= 1)
                return -EINVAL;
 
        rxtrig = bytes_to_fcr_rxtrig(up, bytes);

diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
index eb44420..be65de6 100644 (file)
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -127,7 +127,6 @@ struct uart_8250_port {
        struct list_head        list;           /* ports on this IRQ */
        u32                     capabilities;   /* port capabilities */
        u16                     bugs;           /* port bugs */
-       bool                    fifo_bug;       /* min RX trigger if enabled */
        unsigned int            tx_loadsz;      /* transmit fifo load size */
        unsigned char           acr;
        unsigned char           fcr;