Subject: Re: [PATCH] HPE BMC GXP SUPPORT

From: "Russell King (Oracle)" <[email-masked]>
Date: Fri, 4 Feb 2022 12:05:47 +0000

Hi,

On Wed, Feb 02, 2022 at 10:52:50AM -0600, [email-masked] wrote:
> diff --git a/arch/arm/mach-hpe/Makefile b/arch/arm/mach-hpe/Makefile
> new file mode 100644
> index 000000000000..8b0a91234df4
> --- /dev/null
> +++ b/arch/arm/mach-hpe/Makefile
> @@ -0,0 +1 @@
> +obj-$(CONFIG_ARCH_HPE_GXP) += gxp.o
> diff --git a/arch/arm/mach-hpe/gxp.c b/arch/arm/mach-hpe/gxp.c
> new file mode 100644
> index 000000000000..a37838247948
> --- /dev/null
> +++ b/arch/arm/mach-hpe/gxp.c
> @@ -0,0 +1,62 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (C) 2022 Hewlett-Packard Enterprise Development Company, L.P.
> + *
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +
> +#include <linux/init.h>
> +#include <asm/mach/arch.h>
> +#include <asm/mach/map.h>
> +#include <linux/of.h>
> +#include <linux/of_platform.h>
> +#include <linux/clk-provider.h>
> +#include <linux/clocksource.h>

It's normal to list all linux/ includes before asm/ includes. Please
rearrange.

> +
> +#define IOP_REGS_PHYS_BASE 0xc0000000
> +#define IOP_REGS_VIRT_BASE 0xf0000000
> +#define IOP_REGS_SIZE (240*SZ_1M)
> +
> +#define IOP_EHCI_USBCMD 0x0efe0010
> +
> +static struct map_desc gxp_io_desc[] __initdata = {
> +	{
> +	.virtual	= (unsigned long)IOP_REGS_VIRT_BASE,
> +	.pfn		= __phys_to_pfn(IOP_REGS_PHYS_BASE),
> +	.length		= IOP_REGS_SIZE,
> +	.type		= MT_DEVICE,

If you keep this, please indent the above four lines by one more tab.

> +	},
> +};
> +
> +void __init gxp_map_io(void)
> +{
> +	iotable_init(gxp_io_desc, ARRAY_SIZE(gxp_io_desc));
> +}
> +
> +static void __init gxp_dt_init(void)
> +{
> +	/*reset EHCI host controller for clear start*/
> +	__raw_writel(0x00080002,
> +		(void __iomem *)(IOP_REGS_VIRT_BASE + IOP_EHCI_USBCMD));

Please consider making IOP_REGS_VIRT_BASE a 'void __iomem' pointer, it
being a _virtual_ iomem address. This should save you needing repeated
casts except for the initialiser above.

> +	of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
> +}
> +
> +static void gxp_restart(enum reboot_mode mode, const char *cmd)
> +{
> +	__raw_writel(1, (void __iomem *) IOP_REGS_VIRT_BASE);
> +}
> +
> +static const char * const gxp_board_dt_compat[] = {
> +	"HPE,GXP",
> +	NULL,
> +};
> +
> +DT_MACHINE_START(GXP_DT, "HPE GXP")
> +	.init_machine	= gxp_dt_init,
> +	.map_io		= gxp_map_io,
> +	.restart	= gxp_restart,
> +	.dt_compat	= gxp_board_dt_compat,
> +MACHINE_END
> diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
> index cfb8ea0df3b1..5916dade7608 100644
> --- a/drivers/clocksource/Kconfig
> +++ b/drivers/clocksource/Kconfig
> @@ -617,6 +617,14 @@ config CLKSRC_ST_LPC
>  	  Enable this option to use the Low Power controller timer
>  	  as clocksource.
>  
> +config GXP_TIMER
> +	bool "GXP timer driver"
> +	depends on ARCH_HPE
> +	default y
> +	help
> +	  Provides a driver for the timer control found on HPE
> +	  GXP SOCs. This is required for all GXP SOCs.
> +
>  config ATCPIT100_TIMER
>  	bool "ATCPIT100 timer driver"
>  	depends on NDS32 || COMPILE_TEST
> diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
> index fa5f624eadb6..ffca09ec34de 100644
> --- a/drivers/clocksource/Makefile
> +++ b/drivers/clocksource/Makefile
> @@ -89,3 +89,4 @@ obj-$(CONFIG_GX6605S_TIMER)		+= timer-gx6605s.o
>  obj-$(CONFIG_HYPERV_TIMER)		+= hyperv_timer.o
>  obj-$(CONFIG_MICROCHIP_PIT64B)		+= timer-microchip-pit64b.o
>  obj-$(CONFIG_MSC313E_TIMER)		+= timer-msc313e.o
> +obj-$(CONFIG_GXP_TIMER)			+= gxp_timer.o
> diff --git a/drivers/clocksource/gxp_timer.c b/drivers/clocksource/gxp_timer.c
> new file mode 100644
> index 000000000000..e3c617036e0d
> --- /dev/null
> +++ b/drivers/clocksource/gxp_timer.c
> @@ -0,0 +1,158 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (C) 2022 Hewlett-Packard Enterprise Development Company, L.P.
> + *
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/clockchips.h>
> +#include <linux/clocksource.h>
> +#include <linux/interrupt.h>
> +#include <linux/irqreturn.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/of_platform.h>
> +#include <linux/slab.h>
> +#include <linux/string.h>
> +#include <linux/sched_clock.h>
> +
> +#include <asm/irq.h>

Why do you need asm/irq.h ?

> +
> +#define TIMER0_FREQ 1000000
> +#define TIMER1_FREQ 1000000
> +
> +#define MASK_TCS_ENABLE		0x01
> +#define MASK_TCS_PERIOD		0x02
> +#define MASK_TCS_RELOAD		0x04
> +#define MASK_TCS_TC		0x80
> +
> +struct gxp_timer {
> +	void __iomem *counter;
> +	void __iomem *control;
> +	struct clock_event_device evt;
> +};
> +
> +static void __iomem *system_clock __read_mostly;
> +
> +static u64 notrace gxp_sched_read(void)
> +{
> +	return readl_relaxed(system_clock);
> +}
> +
> +static int gxp_time_set_next_event(unsigned long event,
> +					struct clock_event_device *evt_dev)
> +{
> +	struct gxp_timer *timer = container_of(evt_dev, struct gxp_timer, evt);
> +	/*clear TC by write 1 and disable timer int and counting*/
> +	writeb_relaxed(MASK_TCS_TC, timer->control);
> +	/*update counter value*/
> +	writel_relaxed(event, timer->counter);
> +	/*enable timer counting and int*/
> +	writeb_relaxed(MASK_TCS_TC|MASK_TCS_ENABLE, timer->control);

Spaces around the | please. checkpatch probably should've noticed that.

> +
> +	return 0;
> +}
> +
> +static irqreturn_t gxp_time_interrupt(int irq, void *dev_id)
> +{
> +	struct gxp_timer *timer = dev_id;
> +	void (*event_handler)(struct clock_event_device *timer);
> +
> +

One too many blank lines.

> +	if (readb_relaxed(timer->control) & MASK_TCS_TC) {
> +		writeb_relaxed(MASK_TCS_TC, timer->control);
> +
> +		event_handler = READ_ONCE(timer->evt.event_handler);
> +		if (event_handler)
> +			event_handler(&timer->evt);
> +		return IRQ_HANDLED;
> +	} else {
> +		return IRQ_NONE;
> +	}
> +}
> +
> +static int __init gxp_timer_init(struct device_node *node)
> +{
> +	void __iomem *base_counter;
> +	void __iomem *base_control;
> +	u32 freq;
> +	int ret, irq;
> +	struct gxp_timer *gxp_timer;
> +
> +	base_counter = of_iomap(node, 0);
> +	if (!base_counter) {
> +		pr_err("Can't remap counter registers");
> +		return -ENXIO;
> +	}
> +
> +	base_control = of_iomap(node, 1);
> +	if (!base_control) {
> +		pr_err("Can't remap control registers");

iounmap base_counter?

> +		return -ENXIO;
> +	}
> +
> +	system_clock = of_iomap(node, 2);
> +	if (!system_clock) {
> +		pr_err("Can't remap control registers");

iounmap base_counter and base_control?

> +		return -ENXIO;
> +	}
> +
> +	if (of_property_read_u32(node, "clock-frequency", &freq)) {
> +		pr_err("Can't read clock-frequency\n");
> +		goto err_iounmap;
> +	}
> +
> +	sched_clock_register(gxp_sched_read, 32, freq);
> +	clocksource_mmio_init(system_clock, node->name, freq,
> +				300, 32, clocksource_mmio_readl_up);

We normally align continutation lines in function arguments to the
opening ( thusly:

	clocksource_mmio_init(system_clock, node->name, freq,
			      300, 32, clocksource_mmio_readl_up);

> +
> +	irq = irq_of_parse_and_map(node, 0);
> +	if (irq <= 0) {
> +		ret = -EINVAL;
> +		pr_err("GXP Timer Can't parse IRQ %d", irq);
> +		goto err_iounmap;
> +	}
> +
> +	gxp_timer = kzalloc(sizeof(*gxp_timer), GFP_KERNEL);
> +	if (!gxp_timer) {
> +		ret = -ENOMEM;
> +		goto err_iounmap;
> +	}
> +
> +	gxp_timer->counter = base_counter;
> +	gxp_timer->control = base_control;
> +	gxp_timer->evt.name = node->name;
> +	gxp_timer->evt.rating = 300;
> +	gxp_timer->evt.features = CLOCK_EVT_FEAT_ONESHOT;
> +	gxp_timer->evt.set_next_event = gxp_time_set_next_event;
> +	gxp_timer->evt.cpumask = cpumask_of(0);
> +
> +	if (request_irq(irq, gxp_time_interrupt, IRQF_TIMER | IRQF_SHARED,
> +		node->name, gxp_timer)) {

Again:

	if (request_irq(irq, gxp_time_interrupt, IRQF_TIMER | IRQF_SHARED,
			node->name, gxp_timer)) {

> +		pr_err("%s: request_irq() failed\n", "GXP Timer Tick");

Consider storing the error code from request_irq() and printing it here.
So:

	err = request_irq(...);
	if (err) {
		pr_err("%s: request_irq() failed: %pe\n", "GXP Timer Tick",
		       ERR_PTR(err));

> +		goto err_timer_free;
> +	}
> +
> +	clockevents_config_and_register(&gxp_timer->evt, TIMER0_FREQ,
> +					0xf, 0xffffffff);
> +
> +	pr_info("gxp: system timer (irq = %d)\n", irq);
> +	return 0;
> +
> +
> +err_timer_free:
> +	kfree(gxp_timer);
> +
> +err_iounmap:
> +	iounmap(system_clock);
> +	iounmap(base_control);
> +	iounmap(base_counter);
> +	return ret;
> +}
> +
> +TIMER_OF_DECLARE(gxp, "hpe,gxp-timer", gxp_timer_init);

Thanks.

-- 
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