On Fri, Sep 18, 2015 at 5:51 AM, Andre Przywara <andre.przywara@xxxxxxx> wrote:
>
>> static void pl011_putc(struct uart_port *port, int c)
>> {
>> - while (readl(port->membase + REG_FR) & UART01x_FR_TXFF)
>> + struct uart_amba_port *uap =
>> + container_of(port, struct uart_amba_port, port);
>> +
>> + while (pl011_readw(uap, REG_FR) & UART01x_FR_TXFF)
>> ;
>> - writeb(c, port->membase + REG_DR);
>> - while (readl(port->membase + REG_FR) & UART01x_FR_BUSY)
>> + pl011_writeb(uap, c, REG_DR);
>> + while (pl011_readw(uap, REG_FR) & UART01x_FR_BUSY)
>> ;
>> }
>
> Just for the records, as this has been discussed before: pl011_putc() is
> called by the earlycon code, before the uart_port is actually
> initialized. So we cannot rely on the accessors, but have to use the
> old-fashioned director accessors for this.
>
> Which means you cannot use that approach to get earlycon support for the
> ZTE UART, if I get this correctly. It shouldn't be to hard to introduce
> another earlycon type specificly for that one, copying pl011_early_write
> and pl011_early_console_setup and changing pl011_putc into
> zte_uart_putc. But of course this belongs into the final patch (or a
> separate one), not in this. So I guess you just leave that function
> unchanged in this patch.
How about something like this? It adds the "sbsa32" option to the
earlycon command-line parameter.
static void pl011_putc(struct uart_port *port, int c)
{
while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF)
cpu_relax();
writeb(c, port->membase + UART01x_DR);
while (readl(port->membase + UART01x_FR) & UART01x_FR_BUSY)
cpu_relax();
}
static void pl011_early_write(struct console *con, const char *s, unsigned n)
{
struct earlycon_device *dev = con->data;
uart_console_write(&dev->port, s, n, pl011_putc);
}
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) & UART01x_FR_BUSY)
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);
}
static int __init pl011_early_console_setup(struct earlycon_device *device,
const char *opt)
{
if (!device->port.membase)
return -ENODEV;
if (strcmp(device->options, "sbsa32"))
device->con->write = pl011_early_write_sbsa32;
else
device->con->write = pl011_early_write;
return 0;
}
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