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--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -438,6 +438,20 @@ static void mem_serial_out(struct uart_p
writeb(value, p->membase + offset);
}
+static unsigned int memdelay_serial_in(struct uart_port *p, int offset)
+{
+ struct uart_8250_port *up = (struct uart_8250_port *)p;
+ udelay(up->port.rw_delay);
+ return mem_serial_in(p, offset);
+}
+
+static void memdelay_serial_out(struct uart_port *p, int offset, int value)
+{
+ struct uart_8250_port *up = (struct uart_8250_port *)p;
+ udelay(up->port.rw_delay);
+ mem_serial_out(p, offset, value);
+}
+
static void mem32_serial_out(struct uart_port *p, int offset, int value)
{
offset = offset << p->regshift;
@@ -505,6 +519,11 @@ static void set_io_from_upio(struct uart
p->serial_out = mem32be_serial_out;
break;
+ case UPIO_MEM_DELAY:
+ p->serial_in = memdelay_serial_in;
+ p->serial_out = memdelay_serial_out;
+ break;
+
#if defined(CONFIG_MIPS_ALCHEMY) || defined(CONFIG_SERIAL_8250_RT288X)
case UPIO_AU:
p->serial_in = au_serial_in;
@@ -531,6 +550,7 @@ serial_port_out_sync(struct uart_port *p
case UPIO_MEM:
case UPIO_MEM32:
case UPIO_MEM32BE:
+ case UPIO_MEM_DELAY:
case UPIO_AU:
p->serial_out(p, offset, value);
p->serial_in(p, UART_LCR); /* safe, no side-effects */
@@ -2768,6 +2788,7 @@ static int serial8250_request_std_resour
case UPIO_MEM32:
case UPIO_MEM32BE:
case UPIO_MEM:
+ case UPIO_MEM_DELAY:
if (!port->mapbase)
break;
@@ -2805,6 +2826,7 @@ static void serial8250_release_std_resou
case UPIO_MEM32:
case UPIO_MEM32BE:
case UPIO_MEM:
+ case UPIO_MEM_DELAY:
if (!port->mapbase)
break;
@@ -3693,6 +3715,7 @@ static int serial8250_probe(struct platf
uart.port.set_termios = p->set_termios;
uart.port.pm = p->pm;
uart.port.dev = &dev->dev;
+ uart.port.rw_delay = p->rw_delay;
uart.port.irqflags |= irqflag;
ret = serial8250_register_8250_port(&uart);
if (ret < 0) {
@@ -3849,6 +3872,7 @@ int serial8250_register_8250_port(struct
uart->bugs = up->bugs;
uart->port.mapbase = up->port.mapbase;
uart->port.mapsize = up->port.mapsize;
+ uart->port.rw_delay = up->port.rw_delay;
uart->port.private_data = up->port.private_data;
uart->port.fifosize = up->port.fifosize;
uart->tx_loadsz = up->tx_loadsz;
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -2176,6 +2176,7 @@ uart_report_port(struct uart_driver *drv
snprintf(address, sizeof(address),
"I/O 0x%lx offset 0x%x", port->iobase, port->hub6);
break;
+ case UPIO_MEM_DELAY:
case UPIO_MEM:
case UPIO_MEM32:
case UPIO_MEM32BE:
@@ -2823,6 +2824,7 @@ int uart_match_port(struct uart_port *po
case UPIO_HUB6:
return (port1->iobase == port2->iobase) &&
(port1->hub6 == port2->hub6);
+ case UPIO_MEM_DELAY:
case UPIO_MEM:
case UPIO_MEM32:
case UPIO_MEM32BE:
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -27,6 +27,7 @@ struct plat_serial8250_port {
void *private_data;
unsigned char regshift; /* register shift */
unsigned char iotype; /* UPIO_* */
+ unsigned int rw_delay; /* udelay for slower busses IXP4XX Expansion Bus */
unsigned char hub6;
upf_t flags; /* UPF_* flags */
unsigned int type; /* If UPF_FIXED_TYPE */
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -150,6 +150,7 @@ struct uart_port {
#define UPIO_AU (SERIAL_IO_AU) /* Au1x00 and RT288x type IO */
#define UPIO_TSI (SERIAL_IO_TSI) /* Tsi108/109 type IO */
#define UPIO_MEM32BE (SERIAL_IO_MEM32BE) /* 32b big endian */
+#define UPIO_MEM_DELAY (SERIAL_IO_MEM_DELAY)
unsigned int read_status_mask; /* driver specific */
unsigned int ignore_status_mask; /* driver specific */
@@ -231,6 +232,7 @@ struct uart_port {
int hw_stopped; /* sw-assisted CTS flow state */
unsigned int mctrl; /* current modem ctrl settings */
unsigned int timeout; /* character-based timeout */
+ unsigned int rw_delay; /* udelay for slow busses, IXP4XX Expansion Bus */
unsigned int type; /* port type */
const struct uart_ops *ops;
unsigned int custom_divisor;
--- a/include/uapi/linux/serial.h
+++ b/include/uapi/linux/serial.h
@@ -69,6 +69,7 @@ struct serial_struct {
#define SERIAL_IO_AU 4
#define SERIAL_IO_TSI 5
#define SERIAL_IO_MEM32BE 6
+#define SERIAL_IO_MEM_DELAY 7
#define UART_CLEAR_FIFO 0x01
#define UART_USE_FIFO 0x02
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