Re: [PATCH 1/2] ACPI / scan: Add special handler for Intel Lynxpoint LPSS devices

From: Rafael J. Wysocki
Date: Wed Mar 20 2013 - 14:09:52 EST


On Wednesday, March 20, 2013 09:54:01 AM Mike Turquette wrote:
> Quoting Rafael J. Wysocki (2013-03-02 14:27:52)
> > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> >
> > Devices on the Intel Lynxpoint Low Power Subsystem (LPSS) have some
> > common features that aren't shared with any other platform devices,
> > including the clock and LTR (Latency Tolerance Reporting) registers.
> > It is better to handle those features in common code than to bother
> > device drivers with doing that (I/O functionality-wise the LPSS
> > devices are generally compatible with other devices that don't
> > have those special registers and may be handled by the same drivers).
> >
> > The clock registers of the LPSS devices are now taken care of by
> > the special clk-x86-lpss driver, but the MMIO mappings used for
> > accessing those registers can also be used for accessing the LTR
> > registers on those devices (LTR support for the Lynxpoint LPSS is
> > going to be added by a subsequent patch). Thus it is convenient
> > to add a special ACPI scan handler for the Lynxpoint LPSS devices
> > that will create the MMIO mappings for accessing the clock (and
> > LTR in the future) registers and will register the LPSS devices'
> > clocks, so the clk-x86-lpss driver will only need to take care of
> > the main Lynxpoint LPSS clock.
> >
> > Introduce a special ACPI scan handler for Intel Lynxpoint LPSS
> > devices as described above. This also reduces overhead related to
> > browsing the ACPI namespace in search of the LPSS devices before the
> > registration of their clocks, removes some LPSS-specific (and
> > somewhat ugly) code from acpi_platform.c and shrinks the overall code
> > size slightly.
> >
> > Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
>
> Better late than never. For the clk changes:
>
> Acked-by: Mike Turquette <mturquette@xxxxxxxxxx>

Thanks Mike!

> > ---
> > drivers/acpi/Makefile | 1
> > drivers/acpi/acpi_lpss.c | 163 +++++++++++++++++++++++++++++++++
> > drivers/acpi/acpi_platform.c | 40 --------
> > drivers/acpi/internal.h | 8 +
> > drivers/acpi/scan.c | 1
> > drivers/clk/x86/Makefile | 2
> > drivers/clk/x86/clk-lpss.c | 99 --------------------
> > drivers/clk/x86/clk-lpss.h | 36 -------
> > drivers/clk/x86/clk-lpt.c | 40 --------
> > include/linux/platform_data/clk-lpss.h | 18 +++
> > 10 files changed, 195 insertions(+), 213 deletions(-)
> > create mode 100644 drivers/acpi/acpi_lpss.c
> > delete mode 100644 drivers/clk/x86/clk-lpss.c
> > delete mode 100644 drivers/clk/x86/clk-lpss.h
> > create mode 100644 include/linux/platform_data/clk-lpss.h
> >
> > Index: linux-pm/drivers/acpi/Makefile
> > ===================================================================
> > --- linux-pm.orig/drivers/acpi/Makefile
> > +++ linux-pm/drivers/acpi/Makefile
> > @@ -39,6 +39,7 @@ acpi-y += ec.o
> > acpi-$(CONFIG_ACPI_DOCK) += dock.o
> > acpi-y += pci_root.o pci_link.o pci_irq.o
> > acpi-y += csrt.o
> > +acpi-$(CONFIG_X86_INTEL_LPSS) += acpi_lpss.o
> > acpi-y += acpi_platform.o
> > acpi-y += power.o
> > acpi-y += event.o
> > Index: linux-pm/drivers/acpi/acpi_lpss.c
> > ===================================================================
> > --- /dev/null
> > +++ linux-pm/drivers/acpi/acpi_lpss.c
> > @@ -0,0 +1,163 @@
> > +/*
> > + * ACPI support for Intel Lynxpoint LPSS.
> > + *
> > + * Copyright (C) 2013, Intel Corporation
> > + * Authors: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> > + * Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> > + *
> > + * 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/clk.h>
> > +#include <linux/clkdev.h>
> > +#include <linux/clk-provider.h>
> > +#include <linux/err.h>
> > +#include <linux/io.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/platform_data/clk-lpss.h>
> > +
> > +#include "internal.h"
> > +
> > +ACPI_MODULE_NAME("acpi_lpss");
> > +
> > +#define LPSS_CLK_OFFSET 0x800
> > +#define LPSS_CLK_SIZE 0x04
> > +
> > +struct lpss_device_desc {
> > + bool clk_required;
> > + const char *clk_parent;
> > +};
> > +
> > +struct lpss_private_data {
> > + void __iomem *mmio_base;
> > + resource_size_t mmio_size;
> > + struct clk *clk;
> > + const struct lpss_device_desc *dev_desc;
> > +};
> > +
> > +static struct lpss_device_desc lpt_dev_desc = {
> > + .clk_required = true,
> > + .clk_parent = "lpss_clk",
> > +};
> > +
> > +static const struct acpi_device_id acpi_lpss_device_ids[] = {
> > + /* Lynxpoint LPSS devices */
> > + { "INT33C0", (unsigned long)&lpt_dev_desc },
> > + { "INT33C1", (unsigned long)&lpt_dev_desc },
> > + { "INT33C2", (unsigned long)&lpt_dev_desc },
> > + { "INT33C3", (unsigned long)&lpt_dev_desc },
> > + { "INT33C4", (unsigned long)&lpt_dev_desc },
> > + { "INT33C5", (unsigned long)&lpt_dev_desc },
> > + { "INT33C6", },
> > + { "INT33C7", },
> > +
> > + { }
> > +};
> > +
> > +static int is_memory(struct acpi_resource *res, void *not_used)
> > +{
> > + struct resource r;
> > + return !acpi_dev_resource_memory(res, &r);
> > +}
> > +
> > +/* LPSS main clock device. */
> > +static struct platform_device *lpss_clk_dev;
> > +
> > +static inline void lpt_register_clock_device(void)
> > +{
> > + lpss_clk_dev = platform_device_register_simple("clk-lpt", -1, NULL, 0);
> > +}
> > +
> > +static int register_device_clock(struct acpi_device *adev,
> > + struct lpss_private_data *pdata)
> > +{
> > + const struct lpss_device_desc *dev_desc = pdata->dev_desc;
> > +
> > + if (!lpss_clk_dev)
> > + lpt_register_clock_device();
> > +
> > + if (!dev_desc->clk_parent || !pdata->mmio_base
> > + || pdata->mmio_size < LPSS_CLK_OFFSET + LPSS_CLK_SIZE)
> > + return -ENODATA;
> > +
> > + pdata->clk = clk_register_gate(NULL, dev_name(&adev->dev),
> > + dev_desc->clk_parent, 0,
> > + pdata->mmio_base + LPSS_CLK_OFFSET,
> > + 0, 0, NULL);
> > + if (IS_ERR(pdata->clk))
> > + return PTR_ERR(pdata->clk);
> > +
> > + clk_register_clkdev(pdata->clk, NULL, dev_name(&adev->dev));
> > + return 0;
> > +}
> > +
> > +static int acpi_lpss_create_device(struct acpi_device *adev,
> > + const struct acpi_device_id *id)
> > +{
> > + struct lpss_device_desc *dev_desc;
> > + struct lpss_private_data *pdata;
> > + struct resource_list_entry *rentry;
> > + struct list_head resource_list;
> > + int ret;
> > +
> > + dev_desc = (struct lpss_device_desc *)id->driver_data;
> > + if (!dev_desc)
> > + return acpi_create_platform_device(adev, id);
> > +
> > + pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
> > + if (!pdata)
> > + return -ENOMEM;
> > +
> > + INIT_LIST_HEAD(&resource_list);
> > + ret = acpi_dev_get_resources(adev, &resource_list, is_memory, NULL);
> > + if (ret < 0)
> > + goto err_out;
> > +
> > + list_for_each_entry(rentry, &resource_list, node)
> > + if (resource_type(&rentry->res) == IORESOURCE_MEM) {
> > + pdata->mmio_size = resource_size(&rentry->res);
> > + pdata->mmio_base = ioremap(rentry->res.start,
> > + pdata->mmio_size);
> > + pdata->dev_desc = dev_desc;
> > + break;
> > + }
> > +
> > + acpi_dev_free_resource_list(&resource_list);
> > +
> > + if (dev_desc->clk_required) {
> > + ret = register_device_clock(adev, pdata);
> > + if (ret) {
> > + /*
> > + * Skip the device, but don't terminate the namespace
> > + * scan.
> > + */
> > + ret = 0;
> > + goto err_out;
> > + }
> > + }
> > +
> > + adev->driver_data = pdata;
> > + ret = acpi_create_platform_device(adev, id);
> > + if (ret > 0)
> > + return ret;
> > +
> > + adev->driver_data = NULL;
> > +
> > + err_out:
> > + kfree(pdata);
> > + return ret;
> > +}
> > +
> > +static struct acpi_scan_handler lpss_handler = {
> > + .ids = acpi_lpss_device_ids,
> > + .attach = acpi_lpss_create_device,
> > +};
> > +
> > +void __init acpi_lpss_init(void)
> > +{
> > + if (!lpt_clk_init())
> > + acpi_scan_add_handler(&lpss_handler);
> > +}
> > Index: linux-pm/drivers/acpi/acpi_platform.c
> > ===================================================================
> > --- linux-pm.orig/drivers/acpi/acpi_platform.c
> > +++ linux-pm/drivers/acpi/acpi_platform.c
> > @@ -22,9 +22,6 @@
> >
> > ACPI_MODULE_NAME("platform");
> >
> > -/* Flags for acpi_create_platform_device */
> > -#define ACPI_PLATFORM_CLK BIT(0)
> > -
> > /*
> > * The following ACPI IDs are known to be suitable for representing as
> > * platform devices.
> > @@ -33,33 +30,9 @@ static const struct acpi_device_id acpi_
> >
> > { "PNP0D40" },
> >
> > - /* Haswell LPSS devices */
> > - { "INT33C0", ACPI_PLATFORM_CLK },
> > - { "INT33C1", ACPI_PLATFORM_CLK },
> > - { "INT33C2", ACPI_PLATFORM_CLK },
> > - { "INT33C3", ACPI_PLATFORM_CLK },
> > - { "INT33C4", ACPI_PLATFORM_CLK },
> > - { "INT33C5", ACPI_PLATFORM_CLK },
> > - { "INT33C6", ACPI_PLATFORM_CLK },
> > - { "INT33C7", ACPI_PLATFORM_CLK },
> > -
> > { }
> > };
> >
> > -static int acpi_create_platform_clks(struct acpi_device *adev)
> > -{
> > - static struct platform_device *pdev;
> > -
> > - /* Create Lynxpoint LPSS clocks */
> > - if (!pdev && !strncmp(acpi_device_hid(adev), "INT33C", 6)) {
> > - pdev = platform_device_register_simple("clk-lpt", -1, NULL, 0);
> > - if (IS_ERR(pdev))
> > - return PTR_ERR(pdev);
> > - }
> > -
> > - return 0;
> > -}
> > -
> > /**
> > * acpi_create_platform_device - Create platform device for ACPI device node
> > * @adev: ACPI device node to create a platform device for.
> > @@ -71,10 +44,9 @@ static int acpi_create_platform_clks(str
> > *
> > * Name of the platform device will be the same as @adev's.
> > */
> > -static int acpi_create_platform_device(struct acpi_device *adev,
> > - const struct acpi_device_id *id)
> > +int acpi_create_platform_device(struct acpi_device *adev,
> > + const struct acpi_device_id *id)
> > {
> > - unsigned long flags = id->driver_data;
> > struct platform_device *pdev = NULL;
> > struct acpi_device *acpi_parent;
> > struct platform_device_info pdevinfo;
> > @@ -83,14 +55,6 @@ static int acpi_create_platform_device(s
> > struct resource *resources;
> > int count;
> >
> > - if (flags & ACPI_PLATFORM_CLK) {
> > - int ret = acpi_create_platform_clks(adev);
> > - if (ret) {
> > - dev_err(&adev->dev, "failed to create clocks\n");
> > - return ret;
> > - }
> > - }
> > -
> > /* If the ACPI node already has a physical device attached, skip it. */
> > if (adev->physical_node_count)
> > return 0;
> > Index: linux-pm/drivers/acpi/internal.h
> > ===================================================================
> > --- linux-pm.orig/drivers/acpi/internal.h
> > +++ linux-pm/drivers/acpi/internal.h
> > @@ -48,6 +48,11 @@ int acpi_debugfs_init(void);
> > #else
> > static inline void acpi_debugfs_init(void) { return; }
> > #endif
> > +#ifdef CONFIG_X86_INTEL_LPSS
> > +void acpi_lpss_init(void);
> > +#else
> > +static inline void acpi_lpss_init(void) {}
> > +#endif
> >
> > /* --------------------------------------------------------------------------
> > Device Node Initialization / Removal
> > @@ -131,4 +136,7 @@ static inline void suspend_nvs_restore(v
> > -------------------------------------------------------------------------- */
> > struct platform_device;
> >
> > +int acpi_create_platform_device(struct acpi_device *adev,
> > + const struct acpi_device_id *id);
> > +
> > #endif /* _ACPI_INTERNAL_H_ */
> > Index: linux-pm/drivers/acpi/scan.c
> > ===================================================================
> > --- linux-pm.orig/drivers/acpi/scan.c
> > +++ linux-pm/drivers/acpi/scan.c
> > @@ -1788,6 +1788,7 @@ int __init acpi_scan_init(void)
> > acpi_pci_root_init();
> > acpi_pci_link_init();
> > acpi_platform_init();
> > + acpi_lpss_init();
> > acpi_csrt_init();
> > acpi_container_init();
> > acpi_pci_slot_init();
> > Index: linux-pm/drivers/clk/x86/Makefile
> > ===================================================================
> > --- linux-pm.orig/drivers/clk/x86/Makefile
> > +++ linux-pm/drivers/clk/x86/Makefile
> > @@ -1,2 +1,2 @@
> > -clk-x86-lpss-objs := clk-lpss.o clk-lpt.o
> > +clk-x86-lpss-objs := clk-lpt.o
> > obj-$(CONFIG_X86_INTEL_LPSS) += clk-x86-lpss.o
> > Index: linux-pm/drivers/clk/x86/clk-lpss.c
> > ===================================================================
> > --- linux-pm.orig/drivers/clk/x86/clk-lpss.c
> > +++ /dev/null
> > @@ -1,99 +0,0 @@
> > -/*
> > - * Intel Low Power Subsystem clocks.
> > - *
> > - * Copyright (C) 2013, Intel Corporation
> > - * Authors: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> > - * Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> > - *
> > - * 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/clk.h>
> > -#include <linux/clk-provider.h>
> > -#include <linux/err.h>
> > -#include <linux/io.h>
> > -#include <linux/module.h>
> > -
> > -static int clk_lpss_is_mmio_resource(struct acpi_resource *res, void *data)
> > -{
> > - struct resource r;
> > - return !acpi_dev_resource_memory(res, &r);
> > -}
> > -
> > -static acpi_status clk_lpss_find_mmio(acpi_handle handle, u32 level,
> > - void *data, void **retval)
> > -{
> > - struct resource_list_entry *rentry;
> > - struct list_head resource_list;
> > - struct acpi_device *adev;
> > - const char *uid = data;
> > - int ret;
> > -
> > - if (acpi_bus_get_device(handle, &adev))
> > - return AE_OK;
> > -
> > - if (uid) {
> > - if (!adev->pnp.unique_id)
> > - return AE_OK;
> > - if (strcmp(uid, adev->pnp.unique_id))
> > - return AE_OK;
> > - }
> > -
> > - INIT_LIST_HEAD(&resource_list);
> > - ret = acpi_dev_get_resources(adev, &resource_list,
> > - clk_lpss_is_mmio_resource, NULL);
> > - if (ret < 0)
> > - return AE_NO_MEMORY;
> > -
> > - list_for_each_entry(rentry, &resource_list, node)
> > - if (resource_type(&rentry->res) == IORESOURCE_MEM) {
> > - *(struct resource *)retval = rentry->res;
> > - break;
> > - }
> > -
> > - acpi_dev_free_resource_list(&resource_list);
> > - return AE_OK;
> > -}
> > -
> > -/**
> > - * clk_register_lpss_gate - register LPSS clock gate
> > - * @name: name of this clock gate
> > - * @parent_name: parent clock name
> > - * @hid: ACPI _HID of the device
> > - * @uid: ACPI _UID of the device (optional)
> > - * @offset: LPSS PRV_CLOCK_PARAMS offset
> > - *
> > - * Creates and registers LPSS clock gate.
> > - */
> > -struct clk *clk_register_lpss_gate(const char *name, const char *parent_name,
> > - const char *hid, const char *uid,
> > - unsigned offset)
> > -{
> > - struct resource res = { };
> > - void __iomem *mmio_base;
> > - acpi_status status;
> > - struct clk *clk;
> > -
> > - /*
> > - * First try to look the device and its mmio resource from the
> > - * ACPI namespace.
> > - */
> > - status = acpi_get_devices(hid, clk_lpss_find_mmio, (void *)uid,
> > - (void **)&res);
> > - if (ACPI_FAILURE(status) || !res.start)
> > - return ERR_PTR(-ENODEV);
> > -
> > - mmio_base = ioremap(res.start, resource_size(&res));
> > - if (!mmio_base)
> > - return ERR_PTR(-ENOMEM);
> > -
> > - clk = clk_register_gate(NULL, name, parent_name, 0, mmio_base + offset,
> > - 0, 0, NULL);
> > - if (IS_ERR(clk))
> > - iounmap(mmio_base);
> > -
> > - return clk;
> > -}
> > Index: linux-pm/drivers/clk/x86/clk-lpss.h
> > ===================================================================
> > --- linux-pm.orig/drivers/clk/x86/clk-lpss.h
> > +++ /dev/null
> > @@ -1,36 +0,0 @@
> > -/*
> > - * Intel Low Power Subsystem clock.
> > - *
> > - * Copyright (C) 2013, Intel Corporation
> > - * Authors: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> > - * Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> > - *
> > - * 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.
> > - */
> > -
> > -#ifndef __CLK_LPSS_H
> > -#define __CLK_LPSS_H
> > -
> > -#include <linux/err.h>
> > -#include <linux/errno.h>
> > -#include <linux/clk.h>
> > -
> > -#ifdef CONFIG_ACPI
> > -extern struct clk *clk_register_lpss_gate(const char *name,
> > - const char *parent_name,
> > - const char *hid, const char *uid,
> > - unsigned offset);
> > -#else
> > -static inline struct clk *clk_register_lpss_gate(const char *name,
> > - const char *parent_name,
> > - const char *hid,
> > - const char *uid,
> > - unsigned offset)
> > -{
> > - return ERR_PTR(-ENODEV);
> > -}
> > -#endif
> > -
> > -#endif /* __CLK_LPSS_H */
> > Index: linux-pm/drivers/clk/x86/clk-lpt.c
> > ===================================================================
> > --- linux-pm.orig/drivers/clk/x86/clk-lpt.c
> > +++ linux-pm/drivers/clk/x86/clk-lpt.c
> > @@ -10,7 +10,6 @@
> > * published by the Free Software Foundation.
> > */
> >
> > -#include <linux/acpi.h>
> > #include <linux/clk.h>
> > #include <linux/clkdev.h>
> > #include <linux/clk-provider.h>
> > @@ -18,8 +17,6 @@
> > #include <linux/module.h>
> > #include <linux/platform_device.h>
> >
> > -#include "clk-lpss.h"
> > -
> > #define PRV_CLOCK_PARAMS 0x800
> >
> > static int lpt_clk_probe(struct platform_device *pdev)
> > @@ -34,40 +31,6 @@ static int lpt_clk_probe(struct platform
> >
> > /* Shared DMA clock */
> > clk_register_clkdev(clk, "hclk", "INTL9C60.0.auto");
> > -
> > - /* SPI clocks */
> > - clk = clk_register_lpss_gate("spi0_clk", "lpss_clk", "INT33C0", NULL,
> > - PRV_CLOCK_PARAMS);
> > - if (!IS_ERR(clk))
> > - clk_register_clkdev(clk, NULL, "INT33C0:00");
> > -
> > - clk = clk_register_lpss_gate("spi1_clk", "lpss_clk", "INT33C1", NULL,
> > - PRV_CLOCK_PARAMS);
> > - if (!IS_ERR(clk))
> > - clk_register_clkdev(clk, NULL, "INT33C1:00");
> > -
> > - /* I2C clocks */
> > - clk = clk_register_lpss_gate("i2c0_clk", "lpss_clk", "INT33C2", NULL,
> > - PRV_CLOCK_PARAMS);
> > - if (!IS_ERR(clk))
> > - clk_register_clkdev(clk, NULL, "INT33C2:00");
> > -
> > - clk = clk_register_lpss_gate("i2c1_clk", "lpss_clk", "INT33C3", NULL,
> > - PRV_CLOCK_PARAMS);
> > - if (!IS_ERR(clk))
> > - clk_register_clkdev(clk, NULL, "INT33C3:00");
> > -
> > - /* UART clocks */
> > - clk = clk_register_lpss_gate("uart0_clk", "lpss_clk", "INT33C4", NULL,
> > - PRV_CLOCK_PARAMS);
> > - if (!IS_ERR(clk))
> > - clk_register_clkdev(clk, NULL, "INT33C4:00");
> > -
> > - clk = clk_register_lpss_gate("uart1_clk", "lpss_clk", "INT33C5", NULL,
> > - PRV_CLOCK_PARAMS);
> > - if (!IS_ERR(clk))
> > - clk_register_clkdev(clk, NULL, "INT33C5:00");
> > -
> > return 0;
> > }
> >
> > @@ -79,8 +42,7 @@ static struct platform_driver lpt_clk_dr
> > .probe = lpt_clk_probe,
> > };
> >
> > -static int __init lpt_clk_init(void)
> > +int __init lpt_clk_init(void)
> > {
> > return platform_driver_register(&lpt_clk_driver);
> > }
> > -arch_initcall(lpt_clk_init);
> > Index: linux-pm/include/linux/platform_data/clk-lpss.h
> > ===================================================================
> > --- /dev/null
> > +++ linux-pm/include/linux/platform_data/clk-lpss.h
> > @@ -0,0 +1,18 @@
> > +/*
> > + * Intel Low Power Subsystem clocks.
> > + *
> > + * Copyright (C) 2013, Intel Corporation
> > + * Authors: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> > + * Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> > + *
> > + * 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.
> > + */
> > +
> > +#ifndef __CLK_LPSS_H
> > +#define __CLK_LPSS_H
> > +
> > +extern int lpt_clk_init(void);
> > +
> > +#endif /* __CLK_LPSS_H */
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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