Re: [PATCH 3/5] tty/8250_dw: Add support for OCTEON UARTS.

From: Arnd Bergmann
Date: Wed Jun 19 2013 - 06:00:26 EST


On Tuesday 18 June 2013 12:12:53 David Daney wrote:
> +static unsigned int dw8250_serial_inq(struct uart_port *p, int offset)
> +{
> + offset <<= p->regshift;
> +
> + return (u8)__raw_readq(p->membase + offset);
> +}
> +
> +static void dw8250_serial_outq(struct uart_port *p, int offset, int value)
> +{
> + struct dw8250_data *d = p->private_data;
> +
> + if (offset == UART_LCR)
> + d->last_lcr = value;
> +
> + offset <<= p->regshift;
> + __raw_writeq(value, p->membase + offset);
> + dw8250_serial_inq(p, UART_LCR);
> +}

This breaks building on 32 bit architectures as I found on my daily ARM
builds: __raw_writeq cannot be defined on architectures that don't have
native 64 bit data access instructions. It's also wrong to use the
__raw_* variant, which is not guaranteed to be atomic and is not
endian-safe.

Arnd
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