Add identification support for RZ/V2M 16750 UART.
Currently, RZ/V2M UART is detected as 16550A instead of 16750.
"a4040000.serial: ttyS0 at MMIO 0xa4040000 (irq = 14, base_baud = 3000000)
is a 16550A"
After adding identification support, it is detected as
"a4040000.serial: ttyS0 at MMIO 0xa4040000 (irq = 24, base_baud = 3000000)
is a Renesas RZ/V2M 16750".
Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
---
drivers/tty/serial/8250/8250_port.c | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index e61753c295d5..e4b205e3756b 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -111,6 +111,15 @@ static const struct serial8250_config uart_config[] = {
.rxtrig_bytes = {1, 16, 32, 56},
.flags = UART_CAP_FIFO | UART_CAP_SLEEP | UART_CAP_AFE,
},
+ [PORT_16750] = {
+ .name = "Renesas RZ/V2M 16750",
+ .fifo_size = 64,
+ .tx_loadsz = 64,
+ .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10 |
+ UART_FCR7_64BYTE,
+ .rxtrig_bytes = {1, 16, 32, 56},
+ .flags = UART_CAP_FIFO | UART_CAP_AFE,
+ },
[PORT_STARTECH] = {
.name = "Startech",
.fifo_size = 1,
@@ -1142,6 +1151,24 @@ static void autoconfig_16550a(struct uart_8250_port *up)
return;
}
+ /*
+ * No EFR. Try to detect a Renesas RZ/V2M 16750, which only sets bit 5
+ * of the IIR when 64 byte FIFO mode is enabled.
+ * Try setting/clear bit5 of FCR.
+ */
+ serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
+ status1 = serial_in(up, UART_IIR) & (UART_IIR_64BYTE_FIFO | UART_IIR_FIFO_ENABLED);
+
+ serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO | UART_FCR7_64BYTE);
+ status2 = serial_in(up, UART_IIR) & (UART_IIR_64BYTE_FIFO | UART_IIR_FIFO_ENABLED);
+
+ if (status1 == UART_IIR_FIFO_ENABLED_16550A &&
+ status2 == (UART_IIR_64BYTE_FIFO | UART_IIR_FIFO_ENABLED_16550A)) {
+ up->port.type = PORT_16750;
+ up->capabilities |= UART_CAP_AFE;
+ return;
+ }
+
/*
* Try writing and reading the UART_IER_UUE bit (b6).
* If it works, this is probably one of the Xscale platform's
--
2.25.1
