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

[Mike Turquette <mturquette@linaro.org>]

Quoting Rafael J. Wysocki (2013-03-02 14:27:52)
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> 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@linux.intel.com>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Better late than never.  For the clk changes:

Acked-by: Mike Turquette <mturquette@linaro.org>

> ---
>  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@linux.intel.com>
> + *          Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> + *
> + * 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@linux.intel.com>
> - *         Heikki Krogerus <heikki.krogerus@linux.intel.com>
> - *
> - * 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@linux.intel.com>
> - *         Heikki Krogerus <heikki.krogerus@linux.intel.com>
> - *
> - * 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@linux.intel.com>
> + *          Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> + *
> + * 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 */