diff options
| author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2021-06-18 13:46:32 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-06-21 21:16:31 +1000 |
| commit | 48b545b8018db61ab4978d29c73c16b9fbfad12c (patch) | |
| tree | e0af16bb18cc8c57058e2b27000f14c1f55fc908 /arch/powerpc/kernel/udbg_16550.c | |
| parent | aa9c5adf2f61da39c92280d9336e091852e292ff (diff) | |
powerpc/microwatt: Use standard 16550 UART for console
This adds support to the Microwatt platform to use the standard
16550-style UART which available in the standalone Microwatt FPGA.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/YMwXGCTzedpQje7r@thinks.paulus.ozlabs.org
Diffstat (limited to 'arch/powerpc/kernel/udbg_16550.c')
| -rw-r--r-- | arch/powerpc/kernel/udbg_16550.c | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/udbg_16550.c b/arch/powerpc/kernel/udbg_16550.c index 9356b60d6030..8513aa49614e 100644 --- a/arch/powerpc/kernel/udbg_16550.c +++ b/arch/powerpc/kernel/udbg_16550.c @@ -296,3 +296,42 @@ void __init udbg_init_40x_realmode(void) } #endif /* CONFIG_PPC_EARLY_DEBUG_40x */ + +#ifdef CONFIG_PPC_EARLY_DEBUG_MICROWATT + +#define UDBG_UART_MW_ADDR ((void __iomem *)0xc0002000) + +static u8 udbg_uart_in_isa300_rm(unsigned int reg) +{ + uint64_t msr = mfmsr(); + uint8_t c; + + mtmsr(msr & ~(MSR_EE|MSR_DR)); + isync(); + eieio(); + c = __raw_rm_readb(UDBG_UART_MW_ADDR + (reg << 2)); + mtmsr(msr); + isync(); + return c; +} + +static void udbg_uart_out_isa300_rm(unsigned int reg, u8 val) +{ + uint64_t msr = mfmsr(); + + mtmsr(msr & ~(MSR_EE|MSR_DR)); + isync(); + eieio(); + __raw_rm_writeb(val, UDBG_UART_MW_ADDR + (reg << 2)); + mtmsr(msr); + isync(); +} + +void __init udbg_init_debug_microwatt(void) +{ + udbg_uart_in = udbg_uart_in_isa300_rm; + udbg_uart_out = udbg_uart_out_isa300_rm; + udbg_use_uart(); +} + +#endif /* CONFIG_PPC_EARLY_DEBUG_MICROWATT */ |