| Message ID | 1362117626-2076-1-git-send-email-anup.patel@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, 1 Mar 2013 11:30:26 +0530, Anup Patel <anup.patel@linaro.org> wrote: > This patch adds support for using earlyprintk with 8250/16550 UART ports. > > The 8250/16550 UART can either have 8-bit or 32-bit aligned registers > which is HW vendor dependent. > > Kernel args for 8-bit aligned regs: > earlyprintk=uart8250-8bit,<phys_address> > > Kernel args for 32-bit aligned regs: > earlyprintk=uart8250-16bit,<phys_address> ^^^^^ Please fix this comment to match the actual code. > Signed-off-by: Anup Patel <anup.patel@linaro.org> > --- > arch/arm64/kernel/early_printk.c | 23 +++++++++++++++++++++++ > 1 file changed, 23 insertions(+) > > diff --git a/arch/arm64/kernel/early_printk.c > b/arch/arm64/kernel/early_printk.c > index 7e320a2..d57f300 100644 > --- a/arch/arm64/kernel/early_printk.c > +++ b/arch/arm64/kernel/early_printk.c > @@ -24,11 +24,32 @@ > #include <linux/io.h> > > #include <linux/amba/serial.h> > +#include <uapi/linux/serial_reg.h> You do not need to refer to uapi here. <linux/serial_reg.h> should be enough. > static void __iomem *early_base; > static void (*printch)(char ch); > > /* > + * 8250/16550 (8-bit aligned registers) single character TX. > + */ > +static void uart8250_8bit_printch(char ch) > +{ > + while (!(readb_relaxed(early_base + UART_LSR) & UART_LSR_THRE)) > + ; > + writeb_relaxed(ch, early_base + UART_TX); > +} > + > +/* > + * 8250/16550 (32-bit aligned registers) single character TX. > + */ > +static void uart8250_32bit_printch(char ch) > +{ > + while (!(readl_relaxed(early_base + (UART_LSR << 2)) & UART_LSR_THRE)) > + ; > + writel_relaxed(ch, early_base + (UART_TX << 2)); > +} > + > +/* > * PL011 single character TX. > */ > static void pl011_printch(char ch) > @@ -47,6 +68,8 @@ struct earlycon_match { > > static const struct earlycon_match earlycon_match[] __initconst = { > { .name = "pl011", .printch = pl011_printch, }, > + { .name = "uart8250-8bit", .printch = uart8250_8bit_printch, }, > + { .name = "uart8250-32bit", .printch = uart8250_32bit_printch, }, > {} > };
On 1 March 2013 13:47, Marc Zyngier <marc.zyngier@arm.com> wrote: > > On Fri, 1 Mar 2013 11:30:26 +0530, Anup Patel <anup.patel@linaro.org> > wrote: > > This patch adds support for using earlyprintk with 8250/16550 UART > ports. > > > > The 8250/16550 UART can either have 8-bit or 32-bit aligned registers > > which is HW vendor dependent. > > > > Kernel args for 8-bit aligned regs: > > earlyprintk=uart8250-8bit,<phys_address> > > > > Kernel args for 32-bit aligned regs: > > earlyprintk=uart8250-16bit,<phys_address> > ^^^^^ > > Please fix this comment to match the actual code. Sure, I will fix this. > > > > Signed-off-by: Anup Patel <anup.patel@linaro.org> > > --- > > arch/arm64/kernel/early_printk.c | 23 +++++++++++++++++++++++ > > 1 file changed, 23 insertions(+) > > > > diff --git a/arch/arm64/kernel/early_printk.c > > b/arch/arm64/kernel/early_printk.c > > index 7e320a2..d57f300 100644 > > --- a/arch/arm64/kernel/early_printk.c > > +++ b/arch/arm64/kernel/early_printk.c > > @@ -24,11 +24,32 @@ > > #include <linux/io.h> > > > > #include <linux/amba/serial.h> > > +#include <uapi/linux/serial_reg.h> > > You do not need to refer to uapi here. <linux/serial_reg.h> should be > enough. Ok, I will use <linux/serial_reg.h> > > > > static void __iomem *early_base; > > static void (*printch)(char ch); > > > > /* > > + * 8250/16550 (8-bit aligned registers) single character TX. > > + */ > > +static void uart8250_8bit_printch(char ch) > > +{ > > + while (!(readb_relaxed(early_base + UART_LSR) & UART_LSR_THRE)) > > + ; > > + writeb_relaxed(ch, early_base + UART_TX); > > +} > > + > > +/* > > + * 8250/16550 (32-bit aligned registers) single character TX. > > + */ > > +static void uart8250_32bit_printch(char ch) > > +{ > > + while (!(readl_relaxed(early_base + (UART_LSR << 2)) & UART_LSR_THRE)) > > + ; > > + writel_relaxed(ch, early_base + (UART_TX << 2)); > > +} > > + > > +/* > > * PL011 single character TX. > > */ > > static void pl011_printch(char ch) > > @@ -47,6 +68,8 @@ struct earlycon_match { > > > > static const struct earlycon_match earlycon_match[] __initconst = { > > { .name = "pl011", .printch = pl011_printch, }, > > + { .name = "uart8250-8bit", .printch = uart8250_8bit_printch, }, > > + { .name = "uart8250-32bit", .printch = uart8250_32bit_printch, }, > > {} > > }; > > -- > Fast, cheap, reliable. Pick two. Regards, Anup
diff --git a/arch/arm64/kernel/early_printk.c b/arch/arm64/kernel/early_printk.c index 7e320a2..d57f300 100644 --- a/arch/arm64/kernel/early_printk.c +++ b/arch/arm64/kernel/early_printk.c @@ -24,11 +24,32 @@ #include <linux/io.h> #include <linux/amba/serial.h> +#include <uapi/linux/serial_reg.h> static void __iomem *early_base; static void (*printch)(char ch); /* + * 8250/16550 (8-bit aligned registers) single character TX. + */ +static void uart8250_8bit_printch(char ch) +{ + while (!(readb_relaxed(early_base + UART_LSR) & UART_LSR_THRE)) + ; + writeb_relaxed(ch, early_base + UART_TX); +} + +/* + * 8250/16550 (32-bit aligned registers) single character TX. + */ +static void uart8250_32bit_printch(char ch) +{ + while (!(readl_relaxed(early_base + (UART_LSR << 2)) & UART_LSR_THRE)) + ; + writel_relaxed(ch, early_base + (UART_TX << 2)); +} + +/* * PL011 single character TX. */ static void pl011_printch(char ch) @@ -47,6 +68,8 @@ struct earlycon_match { static const struct earlycon_match earlycon_match[] __initconst = { { .name = "pl011", .printch = pl011_printch, }, + { .name = "uart8250-8bit", .printch = uart8250_8bit_printch, }, + { .name = "uart8250-32bit", .printch = uart8250_32bit_printch, }, {} };
This patch adds support for using earlyprintk with 8250/16550 UART ports. The 8250/16550 UART can either have 8-bit or 32-bit aligned registers which is HW vendor dependent. Kernel args for 8-bit aligned regs: earlyprintk=uart8250-8bit,<phys_address> Kernel args for 32-bit aligned regs: earlyprintk=uart8250-16bit,<phys_address> Signed-off-by: Anup Patel <anup.patel@linaro.org> --- arch/arm64/kernel/early_printk.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+)