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path: root/drivers/tty/serial/8250/8250_pci.c
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Diffstat (limited to 'drivers/tty/serial/8250/8250_pci.c')
-rw-r--r--drivers/tty/serial/8250/8250_pci.c39
1 files changed, 25 insertions, 14 deletions
diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index 5d43de143f33..60f8fffdfd77 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -1324,29 +1324,33 @@ pericom_do_set_divisor(struct uart_port *port, unsigned int baud,
{
int scr;
int lcr;
- int actual_baud;
- int tolerance;
- for (scr = 5 ; scr <= 15 ; scr++) {
- actual_baud = 921600 * 16 / scr;
- tolerance = actual_baud / 50;
+ for (scr = 16; scr > 4; scr--) {
+ unsigned int maxrate = port->uartclk / scr;
+ unsigned int divisor = max(maxrate / baud, 1U);
+ int delta = maxrate / divisor - baud;
- if ((baud < actual_baud + tolerance) &&
- (baud > actual_baud - tolerance)) {
+ if (baud > maxrate + baud / 50)
+ continue;
+ if (delta > baud / 50)
+ divisor++;
+
+ if (divisor > 0xffff)
+ continue;
+
+ /* Update delta due to possible divisor change */
+ delta = maxrate / divisor - baud;
+ if (abs(delta) < baud / 50) {
lcr = serial_port_in(port, UART_LCR);
serial_port_out(port, UART_LCR, lcr | 0x80);
-
- serial_port_out(port, UART_DLL, 1);
- serial_port_out(port, UART_DLM, 0);
+ serial_port_out(port, UART_DLL, divisor & 0xff);
+ serial_port_out(port, UART_DLM, divisor >> 8 & 0xff);
serial_port_out(port, 2, 16 - scr);
serial_port_out(port, UART_LCR, lcr);
return;
- } else if (baud > actual_baud) {
- break;
}
}
- serial8250_do_set_divisor(port, baud, quot, quot_frac);
}
static int pci_pericom_setup(struct serial_private *priv,
const struct pciserial_board *board,
@@ -2291,7 +2295,7 @@ static struct pci_serial_quirk pci_serial_quirks[] = {
.setup = pci_pericom_setup_four_at_eight,
},
{
- .vendor = PCI_DEVICE_ID_ACCESIO_PCIE_ICM_4S,
+ .vendor = PCI_VENDOR_ID_ACCESIO,
.device = PCI_DEVICE_ID_ACCESIO_PCIE_ICM232_4,
.subvendor = PCI_ANY_ID,
.subdevice = PCI_ANY_ID,
@@ -2299,6 +2303,13 @@ static struct pci_serial_quirk pci_serial_quirks[] = {
},
{
.vendor = PCI_VENDOR_ID_ACCESIO,
+ .device = PCI_DEVICE_ID_ACCESIO_PCIE_ICM_4S,
+ .subvendor = PCI_ANY_ID,
+ .subdevice = PCI_ANY_ID,
+ .setup = pci_pericom_setup_four_at_eight,
+ },
+ {
+ .vendor = PCI_VENDOR_ID_ACCESIO,
.device = PCI_DEVICE_ID_ACCESIO_MPCIE_ICM232_4,
.subvendor = PCI_ANY_ID,
.subdevice = PCI_ANY_ID,