If user supplied serial base address via kernel command line and at the same time the word 'mmio' is present, use MMIO accessors.
Signed-off-by: Andy Shevchenko <[email protected]> --- arch/x86/boot/early_serial_console.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/arch/x86/boot/early_serial_console.c b/arch/x86/boot/early_serial_console.c index 98aee6c6e374..cfc9e55cd68a 100644 --- a/arch/x86/boot/early_serial_console.c +++ b/arch/x86/boot/early_serial_console.c @@ -33,6 +33,20 @@ static void io_serial_out(unsigned long addr, int offset, int value) outb(value, addr + offset); } +static void mem8_serial_out(unsigned long addr, int offset, int value) +{ + u8 __iomem *vaddr = (u8 __iomem *)addr; + /* shift implied by pointer type */ + writeb(value, vaddr + offset); +} + +static unsigned int mem8_serial_in(unsigned long addr, int offset) +{ + u8 __iomem *vaddr = (u8 __iomem *)addr; + /* shift implied by pointer type */ + return readb(vaddr + offset); +} + static void early_serial_configure(unsigned long port, int baud) { unsigned char c; @@ -59,6 +73,13 @@ static void early_serial_use_io_accessors(void) serial_out = io_serial_out; } +static void early_serial_use_mmio_accessors(void) +{ + /* It is memory mapped - assume 8-bit alignment */ + serial_in = mem8_serial_in; + serial_out = mem8_serial_out; +} + static void early_serial_init(unsigned long port, int baud) { early_serial_configure(port, baud); @@ -101,12 +122,16 @@ static void parse_earlyprintk(void) /* * make sure we have * "serial,0x3f8,115200" + * "serial,mmio,0xff010180,115200" * "serial,ttyS0,115200" * "ttyS0,115200" */ if (pos == 7 && !strncmp(arg + pos, "0x", 2)) { port = parse_serial_port(arg, pos + 0, &pos); early_serial_use_io_accessors(); + } else if (pos == 7 && !strncmp(arg + pos, "mmio,0x", 7)) { + port = parse_serial_port(arg, pos + 5, &pos); + early_serial_use_mmio_accessors(); } else if (!strncmp(arg + pos, "ttyS", 4)) { static const int bases[] = { 0x3f8, 0x2f8 }; int idx = 0; -- 2.20.1
