[PATCH v2 28/32] cpu: add basic cpu driver for MediaTek ARM chips

[Daniel Golle]

On Wed, Aug 31, 2022 at 07:05:20PM +0800, Weijie Gao wrote:
> Add basic CPU driver used to retrieve CPU model information.
> 

Tested on Bananapi BPi-R3 (MT7986A).

Tested-by: Daniel Golle <daniel at makrotopia.org>

> Signed-off-by: Weijie Gao <weijie.gao at mediatek.com>
> ---
>   v2 changes: new
> ---
>  drivers/cpu/Makefile  |   1 +
>  drivers/cpu/mtk_cpu.c | 106 ++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 107 insertions(+)
>  create mode 100644 drivers/cpu/mtk_cpu.c
> 
> diff --git a/drivers/cpu/Makefile b/drivers/cpu/Makefile
> index 20884b1795..3b38ba9c58 100644
> --- a/drivers/cpu/Makefile
> +++ b/drivers/cpu/Makefile
> @@ -9,6 +9,7 @@ obj-$(CONFIG_CPU) += cpu-uclass.o
>  obj-$(CONFIG_ARCH_BMIPS) += bmips_cpu.o
>  obj-$(CONFIG_ARCH_IMX8) += imx8_cpu.o
>  obj-$(CONFIG_ARCH_AT91) += at91_cpu.o
> +obj-$(CONFIG_ARCH_MEDIATEK) += mtk_cpu.o
>  obj-$(CONFIG_CPU_MPC83XX) += mpc83xx_cpu.o
>  obj-$(CONFIG_CPU_RISCV) += riscv_cpu.o
>  obj-$(CONFIG_CPU_MICROBLAZE) += microblaze_cpu.o
> diff --git a/drivers/cpu/mtk_cpu.c b/drivers/cpu/mtk_cpu.c
> new file mode 100644
> index 0000000000..d00b4c669e
> --- /dev/null
> +++ b/drivers/cpu/mtk_cpu.c
> @@ -0,0 +1,106 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2022 MediaTek Inc. All rights reserved.
> + *
> + * Author: Weijie Gao <weijie.gao at mediatek.com>
> + */
> +
> +#include <linux/types.h>
> +#include <cpu.h>
> +#include <dm.h>
> +#include <fdt_support.h>
> +#include <mapmem.h>
> +#include <asm/global_data.h>
> +#include <linux/io.h>
> +
> +DECLARE_GLOBAL_DATA_PTR;
> +
> +struct mtk_cpu_plat {
> +	void __iomem *hwver_base;
> +};
> +
> +static int mtk_cpu_get_desc(const struct udevice *dev, char *buf, int size)
> +{
> +	struct mtk_cpu_plat *plat = dev_get_plat(dev);
> +
> +	snprintf(buf, size, "MediaTek MT%04X", readl(plat->hwver_base));
> +
> +	return 0;
> +}
> +
> +static int mtk_cpu_get_count(const struct udevice *dev)
> +{
> +	return 1;
> +}
> +
> +static int mtk_cpu_get_vendor(const struct udevice *dev, char *buf, int size)
> +{
> +	snprintf(buf, size, "MediaTek");
> +
> +	return 0;
> +}
> +
> +static int mtk_cpu_probe(struct udevice *dev)
> +{
> +	struct mtk_cpu_plat *plat = dev_get_plat(dev);
> +	const void *fdt = gd->fdt_blob, *reg;
> +	int offset, parent, len, na, ns;
> +	u64 addr;
> +
> +	if (!fdt)
> +		return -ENODEV;
> +
> +	offset = fdt_path_offset(fdt, "/hwver");
> +	if (offset < 0)
> +		return -ENODEV;
> +
> +	parent = fdt_parent_offset(fdt, offset);
> +	if (parent < 0)
> +		return -ENODEV;
> +
> +	na = fdt_address_cells(fdt, parent);
> +	if (na < 1)
> +		return -ENODEV;
> +
> +	ns = fdt_size_cells(gd->fdt_blob, parent);
> +	if (ns < 0)
> +		return -ENODEV;
> +
> +	reg = fdt_getprop(gd->fdt_blob, offset, "reg", &len);
> +	if (!reg)
> +		return -ENODEV;
> +
> +	if (ns)
> +		addr = fdt_translate_address(fdt, offset, reg);
> +	else
> +		addr = fdt_read_number(reg, na);
> +
> +	plat->hwver_base = map_sysmem(addr, 0);
> +	if (!plat->hwver_base)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static const struct cpu_ops mtk_cpu_ops = {
> +	.get_desc	= mtk_cpu_get_desc,
> +	.get_count	= mtk_cpu_get_count,
> +	.get_vendor	= mtk_cpu_get_vendor,
> +};
> +
> +static const struct udevice_id mtk_cpu_ids[] = {
> +	{ .compatible = "arm,cortex-a7" },
> +	{ .compatible = "arm,cortex-a53" },
> +	{ .compatible = "arm,cortex-a73" },
> +	{ /* sentinel */ }
> +};
> +
> +U_BOOT_DRIVER(cpu_mtk) = {
> +	.name		= "mtk-cpu",
> +	.id		= UCLASS_CPU,
> +	.of_match	= mtk_cpu_ids,
> +	.ops		= &mtk_cpu_ops,
> +	.probe		= mtk_cpu_probe,
> +	.plat_auto	= sizeof(struct mtk_cpu_plat),
> +	.flags		= DM_FLAG_PRE_RELOC,
> +};
> -- 
> 2.17.1
>