On Mon, 2 Aug 2010 10:58:39 +0200This feature is used in our U6715 8250 platform serial driver, to avoid
Philippe Langlais<philippe.langlais@xxxxxxxxxxxxxx> wrote:
UART Features extract from STEricsson U6715 data-sheet (arm926 SoC for mobile phone):Confused.
* Fully compatible with industry standard 16C550 and 16C450 from various
manufacturers
* RX and TX 64 byte FIFO reduces CPU interrupts
* Full double buffering
* Modem control signals include CTS, RTS, (and DSR, DTR on UART1 only)
* Automatic baud rate selection
* Manual or automatic RTS/CTS smart hardware flow control
* Programmable serial characteristics:
___ Baud rate generation (50 to 3.25M baud)
___ 5, 6, 7 or 8-bit characters
___ Even, odd or no-parity bit generation and detection
___ 1, 1.5 or 2 stop bit generation
* Independent control of transmit, receive, line status, data set interrupts and FIFOs
* Full status-reporting capabilities
* Separate DMA signaling for RX and TX
* Timed interrupt to spread receive interrupt on known duration
* DMA time-out interrupt to allow detection of end of reception
* Carkit pulse coding and decoding compliant with USB carkit control interface [40]
In 16550A auto-configuration, if the fifo size is 64 then it's an U6 16550A port
Add set_termios hook& export serial8250_do_set_termios to change uart
clock following baudrate
...The patch adds these .set_termios hooks but doesn't actually use them
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -32,6 +32,9 @@ struct plat_serial8250_port {
unsigned int type; /* If UPF_FIXED_TYPE */
unsigned int (*serial_in)(struct uart_port *, int);
void (*serial_out)(struct uart_port *, int, int);
+ void (*set_termios)(struct uart_port *,
+ struct ktermios *new,
+ struct ktermios *old);
};
...
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -279,6 +279,9 @@ struct uart_port {
unsigned char __iomem *membase; /* read/write[bwl] */
unsigned int (*serial_in)(struct uart_port *, int);
void (*serial_out)(struct uart_port *, int, int);
+ void (*set_termios)(struct uart_port *,
+ struct ktermios *new,
+ struct ktermios *old);
unsigned int irq; /* irq number */
unsigned long irqflags; /* irq flags */
unsigned int uartclk; /* base uart clock */
for anything.
The changelog doesn't tell us _why_ this was done (it should) and
lacking any code to look at it's all a bit mysterious.