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Message-ID: <56789147.8070602@mleia.com>
Date: Tue, 22 Dec 2015 01:54:47 +0200
From: Vladimir Zapolskiy <vz@...ia.com>
To: Aleksey Makarov <aleksey.makarov@...aro.org>,
linux-acpi@...r.kernel.org
CC: Russell King <linux@....linux.org.uk>,
Graeme Gregory <graeme.gregory@...aro.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"Rafael J . Wysocki" <rjw@...ysocki.net>,
linux-kernel@...r.kernel.org,
Shannon Zhao <shannon.zhao@...aro.org>,
linux-serial@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
Len Brown <lenb@...nel.org>
Subject: Re: [PATCH v3 1/3] ACPI: amba bus probing support
Hi,
On 21.12.2015 18:41, Aleksey Makarov wrote:
> From: Graeme Gregory <graeme.gregory@...aro.org>
>
> On ARM64 some devices use the AMBA device and not the platform bus for
> probing so add support for this. Uses a dummy clock for apb_pclk as ACPI
> does not have a suitable clock representation and to keep the core
> AMBA bus code unchanged between probing methods.
>
> Signed-off-by: Graeme Gregory <graeme.gregory@...aro.org>
> Signed-off-by: Aleksey Makarov <aleksey.makarov@...aro.org>
> ---
> drivers/acpi/Makefile | 1 +
> drivers/acpi/acpi_amba.c | 149 +++++++++++++++++++++++++++++++++++++++++++++++
> drivers/acpi/internal.h | 5 ++
> 3 files changed, 155 insertions(+)
> create mode 100644 drivers/acpi/acpi_amba.c
>
> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> index 675eaf3..3cf732f 100644
> --- a/drivers/acpi/Makefile
> +++ b/drivers/acpi/Makefile
> @@ -43,6 +43,7 @@ acpi-y += pci_root.o pci_link.o pci_irq.o
> acpi-y += acpi_lpss.o acpi_apd.o
> acpi-y += acpi_platform.o
> acpi-y += acpi_pnp.o
> +acpi-$(CONFIG_ARM_AMBA) += acpi_amba.o
> acpi-y += int340x_thermal.o
> acpi-y += power.o
> acpi-y += event.o
> diff --git a/drivers/acpi/acpi_amba.c b/drivers/acpi/acpi_amba.c
> new file mode 100644
> index 0000000..ebc8913
> --- /dev/null
> +++ b/drivers/acpi/acpi_amba.c
> @@ -0,0 +1,149 @@
> +
> +/*
> + * ACPI support for platform bus type.
> + *
> + * Copyright (C) 2015, Linaro Ltd
> + * Authors: Graeme Gregory <graeme.gregory@...aro.org>
> + *
> + * 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/acpi.h>
> +#include <linux/amba/bus.h>
> +#include <linux/clkdev.h>
> +#include <linux/clk-provider.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/ioport.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +
> +#include "internal.h"
> +
> +static const struct acpi_device_id amba_id_list[] = {
> + {"ARMH0011", 0}, /* PL011 SBSA Uart */
> + {"ARMH0061", 0}, /* PL061 GPIO Device */
> + {"", 0},
> +};
> +
> +static struct clk *amba_dummy_clk;
> +
> +static void amba_register_dummy_clk(void)
> +{
> + struct clk *clk;
> +
> + /* If clock already registered */
> + if (amba_dummy_clk)
> + return;
> +
> + clk = clk_register_fixed_rate(NULL, "apb_pclk", NULL, CLK_IS_ROOT, 0);
> + clk_register_clkdev(clk, "apb_pclk", NULL);
> +
> + amba_dummy_clk = clk;
> +}
> +
> +static int amba_handler_attach(struct acpi_device *adev,
> + const struct acpi_device_id *id)
> +{
> + struct amba_device *dev = NULL;
> + struct acpi_device *acpi_parent;
> + struct resource_entry *rentry;
> + struct list_head resource_list;
> + struct resource *resources = NULL;
> + bool address_found = false;
> + int ret, count, irq_no = 0;
> +
> + /* If the ACPI node already has a physical device attached, skip it. */
> + if (adev->physical_node_count)
> + return 0;
> +
> + amba_register_dummy_clk();
Since it is a single time dummy clock registration, may be it is better
to move it to acpi_amba_init() or somewhere else? I understand that
"apb_pclk" is wanted, but I'm not sure that this driver should serve as
a clock provider.
> + dev = amba_device_alloc(NULL, 0, 0);
> + if (!dev) {
> + pr_err("%s(): amba_device_alloc() failed for %s\n",
> + __func__, dev_name(&adev->dev));
> + return 0;
> + }
> +
> + INIT_LIST_HEAD(&resource_list);
> + count = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
> + if (count < 0) {
> + return 0;
> + } else if (count > 0) {
if you return from one of two if-branches, please don't use if-else nesting
for another one.
> + resources = kmalloc_array(count, sizeof(struct resource),
> + GFP_KERNEL);
resources is never used and it is never freed, why do you allocate it?
> + if (!resources) {
> + acpi_dev_free_resource_list(&resource_list);
> + return 0;
return -ENOMEM; seems to be more appropriate here.
> + }
> + count = 0;
> + list_for_each_entry(rentry, &resource_list, node) {
> + switch (resource_type(rentry->res)) {
> + case IORESOURCE_MEM:
> + if (!address_found) {
> + dev->res = *rentry->res;
> + address_found = true;
> + }
> + break;
> + case IORESOURCE_IRQ:
> + if (irq_no < AMBA_NR_IRQS)
> + dev->irq[irq_no++] = rentry->res->start;
> + break;
> + default:
> + dev_warn(&adev->dev, "Invalid resource\n");
> + }
> + }
> + acpi_dev_free_resource_list(&resource_list);
> + }
> +
> + /*
> + * If the ACPI node has a parent and that parent has a physical device
> + * attached to it, that physical device should be the parent of the
> + * platform device we are about to create.
> + */
> + dev->dev.parent = NULL;
> + acpi_parent = adev->parent;
> + if (acpi_parent) {
> + struct acpi_device_physical_node *entry;
> + struct list_head *list;
> +
> + mutex_lock(&acpi_parent->physical_node_lock);
> + list = &acpi_parent->physical_node_list;
> + if (!list_empty(list)) {
> + entry = list_first_entry(list,
> + struct acpi_device_physical_node,
> + node);
> + dev->dev.parent = entry->dev;
> + }
> + mutex_unlock(&acpi_parent->physical_node_lock);
> + }
> +
> + dev_set_name(&dev->dev, "%s", dev_name(&adev->dev));
> + ACPI_COMPANION_SET(&dev->dev, adev);
> +
> + ret = amba_device_add(dev, &iomem_resource);
> + if (ret) {
> + pr_err("%s(): amba_device_add() failed (%d) for %s\n",
> + __func__, ret, dev_name(&adev->dev));
> + goto err_free;
> + }
> +
> + return 1;
> +
> +err_free:
> + amba_device_put(dev);
> + return 0;
> +}
> +
> +static struct acpi_scan_handler amba_handler = {
> + .ids = amba_id_list,
> + .attach = amba_handler_attach,
> +};
> +
> +void __init acpi_amba_init(void)
> +{
> + acpi_scan_add_handler(&amba_handler);
> +}
> diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
> index 11d87bf..9d58f0c 100644
> --- a/drivers/acpi/internal.h
> +++ b/drivers/acpi/internal.h
> @@ -29,6 +29,11 @@ void acpi_processor_init(void);
> void acpi_platform_init(void);
> void acpi_pnp_init(void);
> void acpi_int340x_thermal_init(void);
> +#ifdef CONFIG_ARM_AMBA
> +void acpi_amba_init(void);
> +#else
> +static inline void acpi_amba_init(void) {}
> +#endif
> int acpi_sysfs_init(void);
> void acpi_container_init(void);
> void acpi_memory_hotplug_init(void);
>
--
With best wishes,
Vladimir
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