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tty: serial: fsl_lpuart: add LS1028A earlycon support 

Add a early_console_setup() for the LS1028A SoC with 32bit, little
endian access. If the bootloader does a fixup of the clock-frequency
node the baudrate divisor register will automatically be set.

Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200306214433.23215-5-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Michael Walle 2020-03-06 22:44:33 +01:00 committed by Greg Kroah-Hartman
parent c2f448cff2
commit e33253f3b7
1 changed files with 43 additions and 8 deletions
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51
drivers/tty/serial/fsl_lpuart.c
View File

@ -1878,11 +1878,12 @@ lpuart_set_termios(struct uart_port *port, struct ktermios *termios,
spin_unlock_irqrestore(&sport->port.lock, flags);
}
static void
lpuart32_serial_setbrg(struct lpuart_port *sport, unsigned int baudrate)
static void __lpuart32_serial_setbrg(struct uart_port *port,
unsigned int baudrate, bool use_rx_dma,
bool use_tx_dma)
{
u32 sbr, osr, baud_diff, tmp_osr, tmp_sbr, tmp_diff, tmp;
u32 clk = sport->port.uartclk;
u32 clk = port->uartclk;
/*
* The idea is to use the best OSR (over-sampling rate) possible.
@ -1928,10 +1929,10 @@ lpuart32_serial_setbrg(struct lpuart_port *sport, unsigned int baudrate)
/* handle buadrate outside acceptable rate */
if (baud_diff > ((baudrate / 100) * 3))
dev_warn(sport->port.dev,
dev_warn(port->dev,
"unacceptable baud rate difference of more than 3%%\n");
tmp = lpuart32_read(&sport->port, UARTBAUD);
tmp = lpuart32_read(port, UARTBAUD);
if ((osr > 3) && (osr < 8))
tmp |= UARTBAUD_BOTHEDGE;
@ -1942,14 +1943,23 @@ lpuart32_serial_setbrg(struct lpuart_port *sport, unsigned int baudrate)
tmp &= ~UARTBAUD_SBR_MASK;
tmp |= sbr & UARTBAUD_SBR_MASK;
if (!sport->lpuart_dma_rx_use)
if (!use_rx_dma)
tmp &= ~UARTBAUD_RDMAE;
if (!sport->lpuart_dma_tx_use)
if (!use_tx_dma)
tmp &= ~UARTBAUD_TDMAE;
lpuart32_write(&sport->port, tmp, UARTBAUD);
lpuart32_write(port, tmp, UARTBAUD);
}
static void lpuart32_serial_setbrg(struct lpuart_port *sport,
unsigned int baudrate)
{
__lpuart32_serial_setbrg(&sport->port, baudrate,
sport->lpuart_dma_rx_use,
sport->lpuart_dma_tx_use);
}
static void
lpuart32_set_termios(struct uart_port *port, struct ktermios *termios,
struct ktermios *old)
@ -2443,6 +2453,30 @@ static int __init lpuart32_early_console_setup(struct earlycon_device *device,
return 0;
}
static int __init ls1028a_early_console_setup(struct earlycon_device *device,
const char *opt)
{
u32 cr;
if (!device->port.membase)
return -ENODEV;
device->port.iotype = UPIO_MEM32;
device->con->write = lpuart32_early_write;
/* set the baudrate */
if (device->port.uartclk && device->baud)
__lpuart32_serial_setbrg(&device->port, device->baud,
false, false);
/* enable transmitter */
cr = lpuart32_read(&device->port, UARTCTRL);
cr |= UARTCTRL_TE;
lpuart32_write(&device->port, cr, UARTCTRL);
return 0;
}
static int __init lpuart32_imx_early_console_setup(struct earlycon_device *device,
const char *opt)
{
@ -2457,6 +2491,7 @@ static int __init lpuart32_imx_early_console_setup(struct earlycon_device *devic
}
OF_EARLYCON_DECLARE(lpuart, "fsl,vf610-lpuart", lpuart_early_console_setup);
OF_EARLYCON_DECLARE(lpuart32, "fsl,ls1021a-lpuart", lpuart32_early_console_setup);
OF_EARLYCON_DECLARE(lpuart32, "fsl,ls1028a-lpuart", ls1028a_early_console_setup);
OF_EARLYCON_DECLARE(lpuart32, "fsl,imx7ulp-lpuart", lpuart32_imx_early_console_setup);
EARLYCON_DECLARE(lpuart, lpuart_early_console_setup);
EARLYCON_DECLARE(lpuart32, lpuart32_early_console_setup);