[PATCH 2/2] serial: amba-pl011: abstract register accessors

Timur Tabi timur at codeaurora.org
Tue Nov 3 08:43:24 PST 2015


Russell King - ARM Linux wrote:
> Thanks for pointing that out... that's a mistake in my patches.  It's
> very difficult to see how we could ever support earlyconsole on ZTE
> without massively overhauling the earlycon stuff.  I'll undo the
> changes there in my series.

How about a command-line option for earlycon?  We do this on our kernel 
for now:

earlycon=pl011,0x3blabla,sbsa32

And then in pl011_early_console_setup(), device->con->write is set to 
either pl011_early_write or to pl011_early_write_sbsa32, which looks 
like this:

static void pl011_putc_sbsa32(struct uart_port *port, int c)
{
         while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF)
                 cpu_relax();
         writel(c, port->membase + UART01x_DR);
         while (!(readl(port->membase + UART01x_FR) & UART011_FR_TXFE))
                 cpu_relax();
}


static void pl011_early_write_sbsa32(struct console *con, const char *s, 
unsigned n)
{
         struct earlycon_device *dev = con->data;

         uart_console_write(&dev->port, s, n, pl011_putc_sbsa32);
}

I would have added this to my patch, but I specifically didn't want to 
add any new functionality.

> Now, as for this patch...
>
>> >  	unsigned int (*get_fifosize)(struct amba_device *dev);
>> >+	u16 (*regreadw)(const void __iomem *addr);
>> >+	void (*regwritew)(u16 val, void __iomem *addr);
>> >+	void (*regwriteb)(u8 val, void __iomem *addr);
> regwriteb() is used nowhere in this patch.

Sorry, I could have sworn I deleted that.  Should I bother posting a 
version 2, since your patch is better?

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