diff options
| author | Matt Redfearn <matt.redfearn@imgtec.com> | 2015-09-08 16:55:34 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-10-04 17:47:49 +0100 |
| commit | 129a45b1a93b93b1c7f3a60ec6d7a276d6142da5 (patch) | |
| tree | 35632fc6ee5b89e0d947c82057285b4c6fcb552a | |
| parent | 20b5af93505cba9d55577f576fcd0d162eb2ad4a (diff) | |
serial: 8250_ingenic: Enable hardware flow control
The Ingenic UART is similar to a standard 16550, but hardware flow control
requires setting a couple of additional, non-standard bits in the MCR.
The non-standard "modem control enable" and "hardware flow control
mode" bits are set when writing to the MCR register, based
on whether the modem control interrupt is active.
Additionally the non-16550 compliant parts of the uart need to be
masked from higher layers.
Tested on Ingenic JZ4780 on MIPS Creator Ci20 board
Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/serial/8250/8250_ingenic.c | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/drivers/tty/serial/8250/8250_ingenic.c b/drivers/tty/serial/8250/8250_ingenic.c index 7c1e4be48e7b..6cc05f88e09f 100644 --- a/drivers/tty/serial/8250/8250_ingenic.c +++ b/drivers/tty/serial/8250/8250_ingenic.c @@ -34,6 +34,9 @@ struct ingenic_uart_data { #define UART_FCR_UME BIT(4) +#define UART_MCR_MDCE BIT(7) +#define UART_MCR_FCM BIT(6) + static struct earlycon_device *early_device; static uint8_t __init early_in(struct uart_port *port, int offset) @@ -129,6 +132,8 @@ OF_EARLYCON_DECLARE(jz4780_uart, "ingenic,jz4780-uart", static void ingenic_uart_serial_out(struct uart_port *p, int offset, int value) { + int ier; + switch (offset) { case UART_FCR: /* UART module enable */ @@ -136,9 +141,22 @@ static void ingenic_uart_serial_out(struct uart_port *p, int offset, int value) break; case UART_IER: + /* Enable receive timeout interrupt with the + * receive line status interrupt */ value |= (value & 0x4) << 2; break; + case UART_MCR: + /* If we have enabled modem status IRQs we should enable modem + * mode. */ + ier = p->serial_in(p, UART_IER); + + if (ier & UART_IER_MSI) + value |= UART_MCR_MDCE | UART_MCR_FCM; + else + value &= ~(UART_MCR_MDCE | UART_MCR_FCM); + break; + default: break; } @@ -146,6 +164,28 @@ static void ingenic_uart_serial_out(struct uart_port *p, int offset, int value) writeb(value, p->membase + (offset << p->regshift)); } +static unsigned int ingenic_uart_serial_in(struct uart_port *p, int offset) +{ + unsigned int value; + + value = readb(p->membase + (offset << p->regshift)); + + /* Hide non-16550 compliant bits from higher levels */ + switch (offset) { + case UART_FCR: + value &= ~UART_FCR_UME; + break; + + case UART_MCR: + value &= ~(UART_MCR_MDCE | UART_MCR_FCM); + break; + + default: + break; + } + return value; +} + static int ingenic_uart_probe(struct platform_device *pdev) { struct uart_8250_port uart = {}; @@ -170,6 +210,7 @@ static int ingenic_uart_probe(struct platform_device *pdev) uart.port.mapbase = regs->start; uart.port.regshift = 2; uart.port.serial_out = ingenic_uart_serial_out; + uart.port.serial_in = ingenic_uart_serial_in; uart.port.irq = irq->start; uart.port.dev = &pdev->dev; |