Commit 48b545b8 authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt Committed by Michael Ellerman
Browse files

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: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
Reviewed-by: default avatarSegher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/YMwXGCTzedpQje7r@thinks.paulus.ozlabs.org
parent aa9c5adf

arch/powerpc/boot/dts/microwatt.dts

+21 −6
Original line number Diff line number Diff line
@@ -6,6 +6,10 @@ 
	model-name = "microwatt";

	compatible = "microwatt-soc";



	aliases {

		serial0 = &UART0;

	};



	reserved-memory {

		#size-cells = <0x02>;

		#address-cells = <0x02>;
@@ -89,12 +93,6 @@ 
		};

	};



	chosen {

		bootargs = "";

		ibm,architecture-vec-5 = [19 00 10 00 00 00 00 00 00 00 00 00 00 00 00 00

					  00 00 00 00 00 00 00 00 40 00 40];

	};



	soc@c0000000 {

		compatible = "simple-bus";

		#address-cells = <1>;
@@ -119,5 +117,22 @@ 
			#interrupt-cells = <2>;

		};



		UART0: serial@2000 {

			device_type = "serial";

			compatible = "ns16550";

			reg = <0x2000 0x8>;

			clock-frequency = <100000000>;

			current-speed = <115200>;

			reg-shift = <2>;

			fifo-size = <16>;

			interrupts = <0x10 0x1>;

		};

	};



	chosen {

		bootargs = "";

		ibm,architecture-vec-5 = [19 00 10 00 00 00 00 00 00 00 00 00 00 00 00 00

					  00 00 00 00 00 00 00 00 40 00 40];

		stdout-path = &UART0;

	};

};

arch/powerpc/kernel/udbg_16550.c

+39 −0
Original line number Diff line number Diff line
@@ -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 */

arch/powerpc/platforms/microwatt/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ config PPC_MICROWATT 
	select PPC_ICS_NATIVE

	select PPC_ICP_NATIVE

	select PPC_NATIVE

	select PPC_UDBG_16550

	help

          This option enables support for FPGA-based Microwatt implementations.

arch/powerpc/platforms/microwatt/setup.c

+2 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <asm/machdep.h>

#include <asm/time.h>

#include <asm/xics.h>

#include <asm/udbg.h>



static void __init microwatt_init_IRQ(void)

{
@@ -35,5 +36,6 @@ define_machine(microwatt) { 
	.name			= "microwatt",

	.probe			= microwatt_probe,

	.init_IRQ		= microwatt_init_IRQ,

	.progress		= udbg_progress,

	.calibrate_decr		= generic_calibrate_decr,

};