[PATCH] tty: amba-pl011: add options to earlycon for 32-bit reg access
From: Peter Hurley <hidden>
Date: 2015-11-06 01:52:08
Also in:
linux-serial
On 11/05/2015 07:37 PM, Timur Tabi wrote:
Add the "sbsa32" command-line option to earlycon to specify that the pl011 registers should be accessed with 32-bit accessors only. This is SBSA platforms Similarly, also add the "zte" option for the ZTE UART. It's functionally similar to the standard PL011, but some registers are at different offsets. Normal console uses the "access_32b" field of the vendor data structure to determine whether the registers needs 32-bit accessors. Early console is used before the vendor data is available, so we need a different mechanism to choose the accessor. Example: earlycon=pl011,0x3ced1000,sbsa32
Perhaps I wasn't clear enough in my previous comments regarding this approach; I see no benefit to re-using the pl011 earlycon definition. Just define a completely new earlycon for sbsa32 (and zte): EARLYCON_DECLARE(sbsa32, sbsa32_early_console_setup); Example: earlycon=sbsa32,0x3ced1000 Regards, Peter Hurley
quoted hunk ↗ jump to hunk
Signed-off-by: Timur Tabi <redacted> --- This patch applies on top of Russell's 12-part amba-pl011.c patchset. drivers/tty/serial/amba-pl011.c | 46 +++++++++++++++++++++++++++++++++++++---- 1 file changed, 42 insertions(+), 4 deletions(-)diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index 373b152..58eda89 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c@@ -2301,10 +2301,10 @@ static struct console amba_console = { static void pl011_putc(struct uart_port *port, int c) { - while (readl(port->membase + REG_FR) & UART01x_FR_TXFF) + while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF) ; - writeb(c, port->membase + REG_DR); - while (readl(port->membase + REG_FR) & UART01x_FR_BUSY) + writeb(c, port->membase + UART01x_DR); + while (readl(port->membase + UART01x_FR) & UART01x_FR_BUSY) ; }@@ -2315,13 +2315,51 @@ static void pl011_early_write(struct console *con, const char *s, unsigned n) 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 void pl011_putc_zte(struct uart_port *port, int c) +{ + while (readl(port->membase + ZX_UART011_FR) & UART01x_FR_TXFF) + cpu_relax(); + writel(c, port->membase + ZX_UART011_DR); + while (readl(port->membase + ZX_UART011_FR) & UART01x_FR_BUSY) + cpu_relax(); +} + +static void pl011_early_write_zte(struct console *con, const char *s, unsigned n) +{ + struct earlycon_device *dev = con->data; + + uart_console_write(&dev->port, s, n, pl011_putc_zte); +} + static int __init pl011_early_console_setup(struct earlycon_device *device, const char *opt) { if (!device->port.membase) return -ENODEV; - device->con->write = pl011_early_write; + if (strcmp(device->options, "sbsa32") == 0) + device->con->write = pl011_early_write_sbsa32; + else if (strcmp(device->options, "zte") == 0) + device->con->write = pl011_early_write_zte; + else + device->con->write = pl011_early_write; + return 0; } EARLYCON_DECLARE(pl011, pl011_early_console_setup);