Re: [PATCH v2 09/13] MIPS: mscc: Add initial support for Microsemi MIPS SoCs

PrasannaKumar Muralidharan
2017-12-19T14:57:06Z

Hi Alexandre,

On 8 December 2017 at 21:16, Alexandre Belloni
<alexandre.belloni@free-electrons.com> wrote:
> Introduce support for the MIPS based Microsemi Ocelot SoCs.
> As the plan is to have all SoCs supported only using device tree, the
> mach directory is simply called mscc.
>
> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
> ---
> arch/mips/Kbuild.platforms | 1 +
> arch/mips/Kconfig | 24 ++++++++++
> arch/mips/mscc/Makefile | 11 +++++
> arch/mips/mscc/Platform | 12 +++++
> arch/mips/mscc/setup.c | 106 +++++++++++++++++++++++++++++++++++++++++++++
> 5 files changed, 154 insertions(+)
> create mode 100644 arch/mips/mscc/Makefile
> create mode 100644 arch/mips/mscc/Platform
> create mode 100644 arch/mips/mscc/setup.c
>
> diff --git a/arch/mips/Kbuild.platforms b/arch/mips/Kbuild.platforms
> index ac7ad54f984f..b3b2f8dc91db 100644
> --- a/arch/mips/Kbuild.platforms
> +++ b/arch/mips/Kbuild.platforms
> @@ -18,6 +18,7 @@ platforms += lantiq
> platforms += lasat
> platforms += loongson32
> platforms += loongson64
> +platforms += mscc
> platforms += mti-malta
> platforms += netlogic
> platforms += paravirt
> diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
> index 350a990fc719..a9db028a0338 100644
> --- a/arch/mips/Kconfig
> +++ b/arch/mips/Kconfig
> @@ -527,6 +527,30 @@ config MIPS_MALTA
> This enables support for the MIPS Technologies Malta evaluation
> board.
>
> +config MSCC_OCELOT
> + bool "Microsemi Ocelot architecture"
> + select BOOT_RAW
> + select CEVT_R4K
> + select CSRC_R4K
> + select IRQ_MIPS_CPU
> + select DMA_NONCOHERENT
> + select SYS_HAS_CPU_MIPS32_R2
> + select SYS_SUPPORTS_32BIT_KERNEL
> + select SYS_SUPPORTS_BIG_ENDIAN
> + select SYS_SUPPORTS_LITTLE_ENDIAN
> + select SYS_HAS_EARLY_PRINTK
> + select USE_GENERIC_EARLY_PRINTK_8250
> + select MSCC_OCELOT_IRQ
> + select PINCTRL
> + select GPIOLIB
> + select COMMON_CLK
> + select USE_OF
> + select BUILTIN_DTB
> + select LIBFDT
> + help
> + This enables support for the Microsemi Ocelot architecture.
> + It builds a generic DT-based kernel image.
> +
> config MACH_PIC32
> bool "Microchip PIC32 Family"
> help
> diff --git a/arch/mips/mscc/Makefile b/arch/mips/mscc/Makefile
> new file mode 100644
> index 000000000000..c96b13546730
> --- /dev/null
> +++ b/arch/mips/mscc/Makefile
> @@ -0,0 +1,11 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR MIT)
> +#
> +# Microsemi MIPS SoC support
> +#
> +# License: Dual MIT/GPL
> +# Copyright (c) 2017 Microsemi Corporation
> +
> +#
> +# Makefile for the Microsemi MIPS SoCs
> +#
> +obj-y := setup.o
> diff --git a/arch/mips/mscc/Platform b/arch/mips/mscc/Platform
> new file mode 100644
> index 000000000000..9ae874c8f136
> --- /dev/null
> +++ b/arch/mips/mscc/Platform
> @@ -0,0 +1,12 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR MIT)
> +#
> +# Microsemi MIPS SoC support
> +#
> +# License: Dual MIT/GPL
> +# Copyright (c) 2017 Microsemi Corporation
> +
> +#
> +# Microsemi Ocelot board(s)
> +#
> +platform-$(CONFIG_MSCC_OCELOT) += mscc/
> +load-$(CONFIG_MSCC_OCELOT) += 0x80100000
> diff --git a/arch/mips/mscc/setup.c b/arch/mips/mscc/setup.c
> new file mode 100644
> index 000000000000..77803edd7bfd
> --- /dev/null
> +++ b/arch/mips/mscc/setup.c
> @@ -0,0 +1,106 @@
> +// SPDX-License-Identifier: (GPL-2.0 OR MIT)
> +/*
> + * Microsemi MIPS SoC support
> + *
> + * License: Dual MIT/GPL
> + * Copyright (c) 2017 Microsemi Corporation
> + */
> +#include <linux/delay.h>
> +#include <linux/export.h>
> +#include <linux/init.h>
> +#include <linux/irq.h>
> +#include <linux/irqchip.h>
> +#include <linux/libfdt.h>
> +#include <linux/of_fdt.h>
> +#include <linux/of_platform.h>
> +#include <linux/reboot.h>
> +
> +#include <asm/time.h>
> +#include <asm/idle.h>
> +#include <asm/prom.h>
> +#include <asm/reboot.h>
> +
> +static void __init ocelot_earlyprintk_init(void)
> +{
> + void __iomem *uart_base;
> +
> + uart_base = ioremap_nocache(0x70100000, 0x0f);
> + setup_8250_early_printk_port((unsigned long)uart_base, 2, 50000);
> +}
> +
> +void __init prom_init(void)
> +{
> + /* Sanity check for defunct bootloader */
> + if (fw_arg0 < 10 && (fw_arg1 & 0xFFF00000) == 0x80000000) {
> + unsigned int prom_argc = fw_arg0;
> + const char **prom_argv = (const char **)fw_arg1;
> +
> + if (prom_argc > 1 && strlen(prom_argv[1]) > 0)
> + /* ignore all built-in args if any f/w args given */
> + strcpy(arcs_cmdline, prom_argv[1]);
> + }
> +}
> +
> +void __init prom_free_prom_memory(void)
> +{
> +}
> +
> +unsigned int get_c0_compare_int(void)
> +{
> + return CP0_LEGACY_COMPARE_IRQ;
> +}
> +
> +void __init plat_time_init(void)
> +{
> + struct device_node *np;
> + u32 freq;
> +
> + np = of_find_node_by_name(NULL, "cpus");
> + if (!np)
> + panic("missing 'cpus' DT node");
> + if (of_property_read_u32(np, "mips-hpt-frequency", &freq) < 0)
> + panic("missing 'mips-hpt-frequency' property");
> + of_node_put(np);
> +
> + mips_hpt_frequency = freq;
> +}
> +
> +void __init arch_init_irq(void)
> +{
> + irqchip_init();
> +}
> +
> +const char *get_system_type(void)
> +{
> + return "Microsemi Ocelot";
> +}
> +
> +static void __init ocelot_late_init(void)
> +{
> + ocelot_earlyprintk_init();
> +}
> +
> +extern void (*late_time_init)(void);
> +
> +void __init plat_mem_setup(void)
> +{
> + /* This has to be done so late because ioremap needs to work */
> + late_time_init = ocelot_late_init;
> +
> + __dt_setup_arch(__dtb_start);
> +}
> +
> +void __init device_tree_init(void)
> +{
> + if (!initial_boot_params)
> + return;
> +
> + unflatten_and_copy_device_tree();
> +}
> +
> +static int __init populate_machine(void)
> +{
> + of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
> + return 0;
> +}
> +arch_initcall(populate_machine);
> --
> 2.15.1
>
>

Given the fact that setup code is very small and most of it is generic
code I strongly believe that it is plausible to make use of generic
code completely. Please have a look at [1] and [2].

1. https://patchwork.kernel.org/patch/9655699/
2. https://patchwork.kernel.org/patch/9655697/

PS: My rb tag stays if this could not be done immediately.

Regards,
PrasannaKumar Muralidharan