From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752509AbcBUR3L (ORCPT ); Sun, 21 Feb 2016 12:29:11 -0500 Received: from mx1.redhat.com ([209.132.183.28]:50078 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751490AbcBUR3H (ORCPT ); Sun, 21 Feb 2016 12:29:07 -0500 Date: Sun, 21 Feb 2016 10:30:26 +0200 From: "Michael S. Tsirkin" To: "Gabriel L. Somlo" Cc: gregkh@linuxfoundation.org, robh+dt@kernel.org, pawel.moll@arm.com, mark.rutland@arm.com, ijc+devicetree@hellion.org.uk, galak@codeaurora.org, arnd@arndb.de, lersek@redhat.com, ralf@linux-mips.org, rmk+kernel@arm.linux.org.uk, eric@anholt.net, hanjun.guo@linaro.org, zajec5@gmail.com, sudeep.holla@arm.com, agross@codeaurora.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, qemu-devel@nongnu.org, imammedo@redhat.com, peter.maydell@linaro.org, leif.lindholm@linaro.org, ard.biesheuvel@linaro.org, pbonzini@redhat.com, kraxel@redhat.com, ehabkost@redhat.com, luto@amacapital.net, stefanha@gmail.com, revol@free.fr, matt@codeblueprint.co.uk, rth@twiddle.net Subject: Re: [PATCH v8 1/4] firmware: introduce sysfs driver for QEMU's fw_cfg device Message-ID: <20160221100557-mutt-send-email-mst@redhat.com> References: <1453990994-17801-1-git-send-email-somlo@cmu.edu> <1453990994-17801-2-git-send-email-somlo@cmu.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1453990994-17801-2-git-send-email-somlo@cmu.edu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 28, 2016 at 09:23:11AM -0500, Gabriel L. Somlo wrote: > From: Gabriel Somlo > > Make fw_cfg entries of type "file" available via sysfs. Entries > are listed under /sys/firmware/qemu_fw_cfg/by_key, in folders > named after each entry's selector key. Filename, selector value, > and size read-only attributes are included for each entry. Also, > a "raw" attribute allows retrieval of the full binary content of > each entry. > > The fw_cfg device can be instantiated automatically from ACPI or > the Device Tree, or manually by using a kernel module (or command > line) parameter, with a syntax outlined in the documentation file. > > Signed-off-by: Gabriel Somlo > --- > .../ABI/testing/sysfs-firmware-qemu_fw_cfg | 58 ++ > drivers/firmware/Kconfig | 19 + > drivers/firmware/Makefile | 1 + > drivers/firmware/qemu_fw_cfg.c | 648 +++++++++++++++++++++ > 4 files changed, 726 insertions(+) > create mode 100644 Documentation/ABI/testing/sysfs-firmware-qemu_fw_cfg > create mode 100644 drivers/firmware/qemu_fw_cfg.c > > diff --git a/Documentation/ABI/testing/sysfs-firmware-qemu_fw_cfg b/Documentation/ABI/testing/sysfs-firmware-qemu_fw_cfg > new file mode 100644 > index 0000000..e9e58d4 > --- /dev/null > +++ b/Documentation/ABI/testing/sysfs-firmware-qemu_fw_cfg > @@ -0,0 +1,58 @@ > +What: /sys/firmware/qemu_fw_cfg/ > +Date: August 2015 > +Contact: Gabriel Somlo > +Description: > + Several different architectures supported by QEMU (x86, arm, > + sun4*, ppc/mac) are provisioned with a firmware configuration > + (fw_cfg) device, originally intended as a way for the host to > + provide configuration data to the guest firmware. Starting > + with QEMU v2.4, arbitrary fw_cfg file entries may be specified > + by the user on the command line, which makes fw_cfg additionally > + useful as an out-of-band, asynchronous mechanism for providing > + configuration data to the guest userspace. > + > + The authoritative guest-side hardware interface documentation > + to the fw_cfg device can be found in "docs/specs/fw_cfg.txt" > + in the QEMU source tree. > + > + === SysFS fw_cfg Interface === > + > + The fw_cfg sysfs interface described in this document is only > + intended to display discoverable blobs (i.e., those registered > + with the file directory), as there is no way to determine the > + presence or size of "legacy" blobs (with selector keys between > + 0x0002 and 0x0018) programmatically. > + > + All fw_cfg information is shown under: > + > + /sys/firmware/qemu_fw_cfg/ > + > + The only legacy blob displayed is the fw_cfg device revision: > + > + /sys/firmware/qemu_fw_cfg/rev > + > + --- Discoverable fw_cfg blobs by selector key --- > + > + All discoverable blobs listed in the fw_cfg file directory are > + displayed as entries named after their unique selector key > + value, e.g.: > + > + /sys/firmware/qemu_fw_cfg/by_key/32 > + /sys/firmware/qemu_fw_cfg/by_key/33 > + /sys/firmware/qemu_fw_cfg/by_key/34 > + ... > + > + Each such fw_cfg sysfs entry has the following values exported > + as attributes: > + > + name : The 56-byte nul-terminated ASCII string used as the > + blob's 'file name' in the fw_cfg directory. > + size : The length of the blob, as given in the fw_cfg > + directory. > + key : The value of the blob's selector key as given in the > + fw_cfg directory. This value is the same as used in > + the parent directory name. > + raw : The raw bytes of the blob, obtained by selecting the > + entry via the control register, and reading a number > + of bytes equal to the blob size from the data > + register. > diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig > index 49a3a11..5130f74 100644 > --- a/drivers/firmware/Kconfig > +++ b/drivers/firmware/Kconfig > @@ -161,6 +161,25 @@ config RASPBERRYPI_FIRMWARE > This option enables support for communicating with the firmware on the > Raspberry Pi. > > +config FW_CFG_SYSFS > + tristate "QEMU fw_cfg device support in sysfs" > + depends on SYSFS && (ARM || ARM64 || PPC_PMAC || SPARC || X86) > + default n > + help > + Say Y or M here to enable the exporting of the QEMU firmware > + configuration (fw_cfg) file entries via sysfs. Entries are > + found under /sys/firmware/fw_cfg when this option is enabled > + and loaded. > + > +config FW_CFG_SYSFS_CMDLINE > + bool "QEMU fw_cfg device parameter parsing" > + depends on FW_CFG_SYSFS > + help > + Allow the qemu_fw_cfg device to be initialized via the kernel > + command line or using a module parameter. > + WARNING: Using incorrect parameters (base address in particular) > + may crash your system. > + > config QCOM_SCM > bool > depends on ARM || ARM64 > diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile > index 48dd417..474bada 100644 > --- a/drivers/firmware/Makefile > +++ b/drivers/firmware/Makefile > @@ -14,6 +14,7 @@ obj-$(CONFIG_ISCSI_IBFT_FIND) += iscsi_ibft_find.o > obj-$(CONFIG_ISCSI_IBFT) += iscsi_ibft.o > obj-$(CONFIG_FIRMWARE_MEMMAP) += memmap.o > obj-$(CONFIG_RASPBERRYPI_FIRMWARE) += raspberrypi.o > +obj-$(CONFIG_FW_CFG_SYSFS) += qemu_fw_cfg.o > obj-$(CONFIG_QCOM_SCM) += qcom_scm.o > obj-$(CONFIG_QCOM_SCM_64) += qcom_scm-64.o > obj-$(CONFIG_QCOM_SCM_32) += qcom_scm-32.o > diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c > new file mode 100644 > index 0000000..83e8a5c > --- /dev/null > +++ b/drivers/firmware/qemu_fw_cfg.c > @@ -0,0 +1,648 @@ > +/* > + * drivers/firmware/qemu_fw_cfg.c > + * > + * Copyright 2015 Carnegie Mellon University > + * > + * Expose entries from QEMU's firmware configuration (fw_cfg) device in > + * sysfs (read-only, under "/sys/firmware/qemu_fw_cfg/..."). > + * > + * The fw_cfg device may be instantiated via either an ACPI node (on x86 > + * and select subsets of aarch64), a Device Tree node (on arm), or using > + * a kernel module (or command line) parameter with the following syntax: > + * > + * [fw_cfg.]ioport=@[::] > + * or > + * [fw_cfg.]mmio=@[::] > + * > + * where: > + * := size of ioport or mmio range > + * := physical base address of ioport or mmio range > + * := (optional) offset of control register > + * := (optional) offset of data register > + * > + * e.g.: > + * fw_cfg.ioport=2@0x510:0:1 (the default on x86) > + * or > + * fw_cfg.mmio=0xA@0x9020000:8:0 (the default on arm) > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > + > +MODULE_AUTHOR("Gabriel L. Somlo "); > +MODULE_DESCRIPTION("QEMU fw_cfg sysfs support"); > +MODULE_LICENSE("GPL"); > + > +/* selector key values for "well-known" fw_cfg entries */ > +#define FW_CFG_SIGNATURE 0x00 > +#define FW_CFG_ID 0x01 > +#define FW_CFG_FILE_DIR 0x19 > + > +/* size in bytes of fw_cfg signature */ > +#define FW_CFG_SIG_SIZE 4 > + > +/* fw_cfg "file name" is up to 56 characters (including terminating nul) */ > +#define FW_CFG_MAX_FILE_PATH 56 > + > +/* fw_cfg file directory entry type */ > +struct fw_cfg_file { > + u32 size; > + u16 select; > + u16 reserved; > + char name[FW_CFG_MAX_FILE_PATH]; > +}; > + > +/* fw_cfg device i/o register addresses */ > +static bool fw_cfg_is_mmio; > +static phys_addr_t fw_cfg_p_base; > +static resource_size_t fw_cfg_p_size; > +static void __iomem *fw_cfg_dev_base; > +static void __iomem *fw_cfg_reg_ctrl; > +static void __iomem *fw_cfg_reg_data; > + > +/* atomic access to fw_cfg device (potentially slow i/o, so using mutex) */ > +static DEFINE_MUTEX(fw_cfg_dev_lock); > + > +/* pick appropriate endianness for selector key */ > +static inline u16 fw_cfg_sel_endianness(u16 key) > +{ > + return fw_cfg_is_mmio ? cpu_to_be16(key) : cpu_to_le16(key); > +} > + > +/* read chunk of given fw_cfg blob (caller responsible for sanity-check) */ > +static inline void fw_cfg_read_blob(u16 key, > + void *buf, loff_t pos, size_t count) > +{ > + mutex_lock(&fw_cfg_dev_lock); > + iowrite16(fw_cfg_sel_endianness(key), fw_cfg_reg_ctrl); > + while (pos-- > 0) > + ioread8(fw_cfg_reg_data); > + ioread8_rep(fw_cfg_reg_data, buf, count); > + mutex_unlock(&fw_cfg_dev_lock); > +} This locking is not enough I think: ACPI might be accessing FW CFG meanwhile, and assuming it's the only owner. I think that on systems that support ACPI, it would be better to use an ACPI interface to read blobs, instead of poking on _CRS and banging on registers directly. This will also make it easier to extend the interface, and support DMA. > + > +/* clean up fw_cfg device i/o */ > +static void fw_cfg_io_cleanup(void) > +{ > + if (fw_cfg_is_mmio) { > + iounmap(fw_cfg_dev_base); > + release_mem_region(fw_cfg_p_base, fw_cfg_p_size); > + } else { > + ioport_unmap(fw_cfg_dev_base); > + release_region(fw_cfg_p_base, fw_cfg_p_size); > + } > +} > + > +/* arch-specific ctrl & data register offsets are not available in ACPI, DT */ So for all arches which support ACPI, I think this driver should just rely on ACPI. > +#if !(defined(FW_CFG_CTRL_OFF) && defined(FW_CTRL_DATA_OFF)) > +# if (defined(CONFIG_ARM) || defined(CONFIG_ARM64)) > +# define FW_CFG_CTRL_OFF 0x08 > +# define FW_CFG_DATA_OFF 0x00 > +# elif (defined(CONFIG_PPC_PMAC) || defined(CONFIG_SPARC32)) /* ppc/mac,sun4m */ > +# define FW_CFG_CTRL_OFF 0x00 > +# define FW_CFG_DATA_OFF 0x02 > +# elif (defined(CONFIG_X86) || defined(CONFIG_SPARC64)) /* x86, sun4u */ > +# define FW_CFG_CTRL_OFF 0x00 > +# define FW_CFG_DATA_OFF 0x01 > +# else > +# warning "QEMU FW_CFG may not be available on this architecture!" > +# define FW_CFG_CTRL_OFF 0x00 > +# define FW_CFG_DATA_OFF 0x01 Better not try hacks like this, they are hard to support down the road. Please only list what is tested and actually exposed by QEMU. > +# endif > +#endif > + > +/* initialize fw_cfg device i/o from platform data */ > +static int fw_cfg_do_platform_probe(struct platform_device *pdev) > +{ > + char sig[FW_CFG_SIG_SIZE]; > + struct resource *range, *ctrl, *data; > + > + /* acquire i/o range details */ > + fw_cfg_is_mmio = false; > + range = platform_get_resource(pdev, IORESOURCE_IO, 0); > + if (!range) { > + fw_cfg_is_mmio = true; > + range = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + if (!range) > + return -EINVAL; > + } > + fw_cfg_p_base = range->start; > + fw_cfg_p_size = resource_size(range); > + > + if (fw_cfg_is_mmio) { > + if (!request_mem_region(fw_cfg_p_base, > + fw_cfg_p_size, "fw_cfg_mem")) > + return -EBUSY; > + fw_cfg_dev_base = ioremap(fw_cfg_p_base, fw_cfg_p_size); > + if (!fw_cfg_dev_base) { > + release_mem_region(fw_cfg_p_base, fw_cfg_p_size); > + return -EFAULT; > + } > + } else { > + if (!request_region(fw_cfg_p_base, > + fw_cfg_p_size, "fw_cfg_io")) > + return -EBUSY; > + fw_cfg_dev_base = ioport_map(fw_cfg_p_base, fw_cfg_p_size); > + if (!fw_cfg_dev_base) { > + release_region(fw_cfg_p_base, fw_cfg_p_size); > + return -EFAULT; > + } > + } > + > + /* were custom register offsets provided (e.g. on the command line)? */ > + ctrl = platform_get_resource_byname(pdev, IORESOURCE_REG, "ctrl"); > + data = platform_get_resource_byname(pdev, IORESOURCE_REG, "data"); > + if (ctrl && data) { > + fw_cfg_reg_ctrl = fw_cfg_dev_base + ctrl->start; > + fw_cfg_reg_data = fw_cfg_dev_base + data->start; > + } else { > + /* use architecture-specific offsets */ > + fw_cfg_reg_ctrl = fw_cfg_dev_base + FW_CFG_CTRL_OFF; > + fw_cfg_reg_data = fw_cfg_dev_base + FW_CFG_DATA_OFF; > + } > + > + /* verify fw_cfg device signature */ > + fw_cfg_read_blob(FW_CFG_SIGNATURE, sig, 0, FW_CFG_SIG_SIZE); > + if (memcmp(sig, "QEMU", FW_CFG_SIG_SIZE) != 0) { > + fw_cfg_io_cleanup(); > + return -ENODEV; > + } > + > + return 0; > +} > + > +/* fw_cfg revision attribute, in /sys/firmware/qemu_fw_cfg top-level dir. */ > +static u32 fw_cfg_rev; > + > +static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf) > +{ > + return sprintf(buf, "%u\n", fw_cfg_rev); > +} > + > +static const struct { > + struct attribute attr; > + ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf); > +} fw_cfg_rev_attr = { > + .attr = { .name = "rev", .mode = S_IRUSR }, > + .show = fw_cfg_showrev, > +}; > + > +/* fw_cfg_sysfs_entry type */ > +struct fw_cfg_sysfs_entry { > + struct kobject kobj; > + struct fw_cfg_file f; > + struct list_head list; > +}; > + > +/* get fw_cfg_sysfs_entry from kobject member */ > +static inline struct fw_cfg_sysfs_entry *to_entry(struct kobject *kobj) > +{ > + return container_of(kobj, struct fw_cfg_sysfs_entry, kobj); > +} > + > +/* fw_cfg_sysfs_attribute type */ > +struct fw_cfg_sysfs_attribute { > + struct attribute attr; > + ssize_t (*show)(struct fw_cfg_sysfs_entry *entry, char *buf); > +}; > + > +/* get fw_cfg_sysfs_attribute from attribute member */ > +static inline struct fw_cfg_sysfs_attribute *to_attr(struct attribute *attr) > +{ > + return container_of(attr, struct fw_cfg_sysfs_attribute, attr); > +} > + > +/* global cache of fw_cfg_sysfs_entry objects */ > +static LIST_HEAD(fw_cfg_entry_cache); > + > +/* kobjects removed lazily by kernel, mutual exclusion needed */ > +static DEFINE_SPINLOCK(fw_cfg_cache_lock); > + > +static inline void fw_cfg_sysfs_cache_enlist(struct fw_cfg_sysfs_entry *entry) > +{ > + spin_lock(&fw_cfg_cache_lock); > + list_add_tail(&entry->list, &fw_cfg_entry_cache); > + spin_unlock(&fw_cfg_cache_lock); > +} > + > +static inline void fw_cfg_sysfs_cache_delist(struct fw_cfg_sysfs_entry *entry) > +{ > + spin_lock(&fw_cfg_cache_lock); > + list_del(&entry->list); > + spin_unlock(&fw_cfg_cache_lock); > +} > + > +static void fw_cfg_sysfs_cache_cleanup(void) > +{ > + struct fw_cfg_sysfs_entry *entry, *next; > + > + list_for_each_entry_safe(entry, next, &fw_cfg_entry_cache, list) { > + /* will end up invoking fw_cfg_sysfs_cache_delist() > + * via each object's release() method (i.e. destructor) > + */ > + kobject_put(&entry->kobj); > + } > +} > + > +/* default_attrs: per-entry attributes and show methods */ > + > +#define FW_CFG_SYSFS_ATTR(_attr) \ > +struct fw_cfg_sysfs_attribute fw_cfg_sysfs_attr_##_attr = { \ > + .attr = { .name = __stringify(_attr), .mode = S_IRUSR }, \ > + .show = fw_cfg_sysfs_show_##_attr, \ > +} > + > +static ssize_t fw_cfg_sysfs_show_size(struct fw_cfg_sysfs_entry *e, char *buf) > +{ > + return sprintf(buf, "%u\n", e->f.size); > +} > + > +static ssize_t fw_cfg_sysfs_show_key(struct fw_cfg_sysfs_entry *e, char *buf) > +{ > + return sprintf(buf, "%u\n", e->f.select); > +} > + > +static ssize_t fw_cfg_sysfs_show_name(struct fw_cfg_sysfs_entry *e, char *buf) > +{ > + return sprintf(buf, "%s\n", e->f.name); > +} > + > +static FW_CFG_SYSFS_ATTR(size); > +static FW_CFG_SYSFS_ATTR(key); > +static FW_CFG_SYSFS_ATTR(name); > + > +static struct attribute *fw_cfg_sysfs_entry_attrs[] = { > + &fw_cfg_sysfs_attr_size.attr, > + &fw_cfg_sysfs_attr_key.attr, > + &fw_cfg_sysfs_attr_name.attr, > + NULL, > +}; > + > +/* sysfs_ops: find fw_cfg_[entry, attribute] and call appropriate show method */ > +static ssize_t fw_cfg_sysfs_attr_show(struct kobject *kobj, struct attribute *a, > + char *buf) > +{ > + struct fw_cfg_sysfs_entry *entry = to_entry(kobj); > + struct fw_cfg_sysfs_attribute *attr = to_attr(a); > + > + return attr->show(entry, buf); > +} > + > +static const struct sysfs_ops fw_cfg_sysfs_attr_ops = { > + .show = fw_cfg_sysfs_attr_show, > +}; > + > +/* release: destructor, to be called via kobject_put() */ > +static void fw_cfg_sysfs_release_entry(struct kobject *kobj) > +{ > + struct fw_cfg_sysfs_entry *entry = to_entry(kobj); > + > + fw_cfg_sysfs_cache_delist(entry); > + kfree(entry); > +} > + > +/* kobj_type: ties together all properties required to register an entry */ > +static struct kobj_type fw_cfg_sysfs_entry_ktype = { > + .default_attrs = fw_cfg_sysfs_entry_attrs, > + .sysfs_ops = &fw_cfg_sysfs_attr_ops, > + .release = fw_cfg_sysfs_release_entry, > +}; > + > +/* raw-read method and attribute */ > +static ssize_t fw_cfg_sysfs_read_raw(struct file *filp, struct kobject *kobj, > + struct bin_attribute *bin_attr, > + char *buf, loff_t pos, size_t count) > +{ > + struct fw_cfg_sysfs_entry *entry = to_entry(kobj); > + > + if (pos > entry->f.size) > + return -EINVAL; > + > + if (count > entry->f.size - pos) > + count = entry->f.size - pos; > + > + fw_cfg_read_blob(entry->f.select, buf, pos, count); > + return count; > +} > + > +static struct bin_attribute fw_cfg_sysfs_attr_raw = { > + .attr = { .name = "raw", .mode = S_IRUSR }, > + .read = fw_cfg_sysfs_read_raw, > +}; > + > +/* kobjects representing top-level and by_key folders */ > +static struct kobject *fw_cfg_top_ko; > +static struct kobject *fw_cfg_sel_ko; > + > +/* register an individual fw_cfg file */ > +static int fw_cfg_register_file(const struct fw_cfg_file *f) > +{ > + int err; > + struct fw_cfg_sysfs_entry *entry; > + > + /* allocate new entry */ > + entry = kzalloc(sizeof(*entry), GFP_KERNEL); > + if (!entry) > + return -ENOMEM; > + > + /* set file entry information */ > + memcpy(&entry->f, f, sizeof(struct fw_cfg_file)); > + > + /* register entry under "/sys/firmware/qemu_fw_cfg/by_key/" */ > + err = kobject_init_and_add(&entry->kobj, &fw_cfg_sysfs_entry_ktype, > + fw_cfg_sel_ko, "%d", entry->f.select); > + if (err) > + goto err_register; > + > + /* add raw binary content access */ > + err = sysfs_create_bin_file(&entry->kobj, &fw_cfg_sysfs_attr_raw); > + if (err) > + goto err_add_raw; > + > + /* success, add entry to global cache */ > + fw_cfg_sysfs_cache_enlist(entry); > + return 0; > + > +err_add_raw: > + kobject_del(&entry->kobj); > +err_register: > + kfree(entry); > + return err; > +} > + > +/* iterate over all fw_cfg directory entries, registering each one */ > +static int fw_cfg_register_dir_entries(void) > +{ > + int ret = 0; > + u32 count, i; > + struct fw_cfg_file *dir; > + size_t dir_size; > + > + fw_cfg_read_blob(FW_CFG_FILE_DIR, &count, 0, sizeof(count)); > + count = be32_to_cpu(count); > + dir_size = count * sizeof(struct fw_cfg_file); > + > + dir = kmalloc(dir_size, GFP_KERNEL); > + if (!dir) > + return -ENOMEM; > + > + fw_cfg_read_blob(FW_CFG_FILE_DIR, dir, sizeof(count), dir_size); > + > + for (i = 0; i < count; i++) { > + dir[i].size = be32_to_cpu(dir[i].size); > + dir[i].select = be16_to_cpu(dir[i].select); > + ret = fw_cfg_register_file(&dir[i]); > + if (ret) > + break; > + } > + > + kfree(dir); > + return ret; > +} > + > +/* unregister top-level or by_key folder */ > +static inline void fw_cfg_kobj_cleanup(struct kobject *kobj) > +{ > + kobject_del(kobj); > + kobject_put(kobj); > +} > + > +static int fw_cfg_sysfs_probe(struct platform_device *pdev) > +{ > + int err; > + > + /* NOTE: If we supported multiple fw_cfg devices, we'd first create > + * a subdirectory named after e.g. pdev->id, then hang per-device > + * by_key subdirectories underneath it. However, only > + * one fw_cfg device exist system-wide, so if one was already found > + * earlier, we might as well stop here. > + */ > + if (fw_cfg_sel_ko) > + return -EBUSY; > + > + /* create by_key subdirectory of /sys/firmware/qemu_fw_cfg/ */ > + err = -ENOMEM; > + fw_cfg_sel_ko = kobject_create_and_add("by_key", fw_cfg_top_ko); > + if (!fw_cfg_sel_ko) > + goto err_sel; > + > + /* initialize fw_cfg device i/o from platform data */ > + err = fw_cfg_do_platform_probe(pdev); > + if (err) > + goto err_probe; > + > + /* get revision number, add matching top-level attribute */ > + fw_cfg_read_blob(FW_CFG_ID, &fw_cfg_rev, 0, sizeof(fw_cfg_rev)); > + fw_cfg_rev = le32_to_cpu(fw_cfg_rev); > + err = sysfs_create_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr); > + if (err) > + goto err_rev; > + > + /* process fw_cfg file directory entry, registering each file */ > + err = fw_cfg_register_dir_entries(); > + if (err) > + goto err_dir; > + > + /* success */ > + pr_debug("fw_cfg: loaded.\n"); > + return 0; > + > +err_dir: > + fw_cfg_sysfs_cache_cleanup(); > + sysfs_remove_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr); > +err_rev: > + fw_cfg_io_cleanup(); > +err_probe: > + fw_cfg_kobj_cleanup(fw_cfg_sel_ko); > +err_sel: > + return err; > +} > + > +static int fw_cfg_sysfs_remove(struct platform_device *pdev) > +{ > + pr_debug("fw_cfg: unloading.\n"); > + fw_cfg_sysfs_cache_cleanup(); > + fw_cfg_kobj_cleanup(fw_cfg_sel_ko); > + fw_cfg_io_cleanup(); > + return 0; > +} > + > +static const struct of_device_id fw_cfg_sysfs_mmio_match[] = { > + { .compatible = "qemu,fw-cfg-mmio", }, > + {}, > +}; > +MODULE_DEVICE_TABLE(of, fw_cfg_sysfs_mmio_match); > + > +#ifdef CONFIG_ACPI > +static const struct acpi_device_id fw_cfg_sysfs_acpi_match[] = { > + { "QEMU0002", }, > + {}, > +}; > +MODULE_DEVICE_TABLE(acpi, fw_cfg_sysfs_acpi_match); > +#endif > + > +static struct platform_driver fw_cfg_sysfs_driver = { > + .probe = fw_cfg_sysfs_probe, > + .remove = fw_cfg_sysfs_remove, > + .driver = { > + .name = "fw_cfg", > + .of_match_table = fw_cfg_sysfs_mmio_match, > + .acpi_match_table = ACPI_PTR(fw_cfg_sysfs_acpi_match), > + }, > +}; > + > +#ifdef CONFIG_FW_CFG_SYSFS_CMDLINE > + > +static struct platform_device *fw_cfg_cmdline_dev; > + > +/* this probably belongs in e.g. include/linux/types.h, > + * but right now we are the only ones doing it... > + */ > +#ifdef CONFIG_PHYS_ADDR_T_64BIT > +#define __PHYS_ADDR_PREFIX "ll" > +#else > +#define __PHYS_ADDR_PREFIX "" > +#endif > + > +/* use special scanf/printf modifier for phys_addr_t, resource_size_t */ > +#define PH_ADDR_SCAN_FMT "@%" __PHYS_ADDR_PREFIX "i%n" \ > + ":%" __PHYS_ADDR_PREFIX "i" \ > + ":%" __PHYS_ADDR_PREFIX "i%n" > + > +#define PH_ADDR_PR_1_FMT "0x%" __PHYS_ADDR_PREFIX "x@" \ > + "0x%" __PHYS_ADDR_PREFIX "x" > + > +#define PH_ADDR_PR_3_FMT PH_ADDR_PR_1_FMT \ > + ":%" __PHYS_ADDR_PREFIX "u" \ > + ":%" __PHYS_ADDR_PREFIX "u" > + > +static int fw_cfg_cmdline_set(const char *arg, const struct kernel_param *kp) > +{ > + struct resource res[3] = {}; > + char *str; > + phys_addr_t base; > + resource_size_t size, ctrl_off, data_off; > + int processed, consumed = 0; > + > + /* only one fw_cfg device can exist system-wide, so if one > + * was processed on the command line already, we might as > + * well stop here. > + */ > + if (fw_cfg_cmdline_dev) { > + /* avoid leaking previously registered device */ > + platform_device_unregister(fw_cfg_cmdline_dev); > + return -EINVAL; > + } > + > + /* consume "" portion of command line argument */ > + size = memparse(arg, &str); > + > + /* get "@[::]" chunks */ > + processed = sscanf(str, PH_ADDR_SCAN_FMT, > + &base, &consumed, > + &ctrl_off, &data_off, &consumed); > + > + /* sscanf() must process precisely 1 or 3 chunks: > + * is mandatory, optionally followed by > + * and ; > + * there must be no extra characters after the last chunk, > + * so str[consumed] must be '\0'. > + */ > + if (str[consumed] || > + (processed != 1 && processed != 3)) > + return -EINVAL; > + > + res[0].start = base; > + res[0].end = base + size - 1; > + res[0].flags = !strcmp(kp->name, "mmio") ? IORESOURCE_MEM : > + IORESOURCE_IO; > + > + /* insert register offsets, if provided */ > + if (processed > 1) { > + res[1].name = "ctrl"; > + res[1].start = ctrl_off; > + res[1].flags = IORESOURCE_REG; > + res[2].name = "data"; > + res[2].start = data_off; > + res[2].flags = IORESOURCE_REG; > + } > + > + /* "processed" happens to nicely match the number of resources > + * we need to pass in to this platform device. > + */ > + fw_cfg_cmdline_dev = platform_device_register_simple("fw_cfg", > + PLATFORM_DEVID_NONE, res, processed); > + if (IS_ERR(fw_cfg_cmdline_dev)) > + return PTR_ERR(fw_cfg_cmdline_dev); > + > + return 0; > +} > + > +static int fw_cfg_cmdline_get(char *buf, const struct kernel_param *kp) > +{ > + /* stay silent if device was not configured via the command > + * line, or if the parameter name (ioport/mmio) doesn't match > + * the device setting > + */ > + if (!fw_cfg_cmdline_dev || > + (!strcmp(kp->name, "mmio") ^ > + (fw_cfg_cmdline_dev->resource[0].flags == IORESOURCE_MEM))) > + return 0; > + > + switch (fw_cfg_cmdline_dev->num_resources) { > + case 1: > + return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_1_FMT, > + resource_size(&fw_cfg_cmdline_dev->resource[0]), > + fw_cfg_cmdline_dev->resource[0].start); > + case 3: > + return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_3_FMT, > + resource_size(&fw_cfg_cmdline_dev->resource[0]), > + fw_cfg_cmdline_dev->resource[0].start, > + fw_cfg_cmdline_dev->resource[1].start, > + fw_cfg_cmdline_dev->resource[2].start); > + } > + > + /* Should never get here */ > + WARN(1, "Unexpected number of resources: %d\n", > + fw_cfg_cmdline_dev->num_resources); > + return 0; > +} > + > +static const struct kernel_param_ops fw_cfg_cmdline_param_ops = { > + .set = fw_cfg_cmdline_set, > + .get = fw_cfg_cmdline_get, > +}; > + > +device_param_cb(ioport, &fw_cfg_cmdline_param_ops, NULL, S_IRUSR); > +device_param_cb(mmio, &fw_cfg_cmdline_param_ops, NULL, S_IRUSR); > + > +#endif /* CONFIG_FW_CFG_SYSFS_CMDLINE */ > + > +static int __init fw_cfg_sysfs_init(void) > +{ > + /* create /sys/firmware/qemu_fw_cfg/ top level directory */ > + fw_cfg_top_ko = kobject_create_and_add("qemu_fw_cfg", firmware_kobj); > + if (!fw_cfg_top_ko) > + return -ENOMEM; > + > + return platform_driver_register(&fw_cfg_sysfs_driver); > +} > + > +static void __exit fw_cfg_sysfs_exit(void) > +{ > + platform_driver_unregister(&fw_cfg_sysfs_driver); > + > +#ifdef CONFIG_FW_CFG_SYSFS_CMDLINE > + platform_device_unregister(fw_cfg_cmdline_dev); > +#endif > + > + /* clean up /sys/firmware/qemu_fw_cfg/ */ > + fw_cfg_kobj_cleanup(fw_cfg_top_ko); > +} > + > +module_init(fw_cfg_sysfs_init); > +module_exit(fw_cfg_sysfs_exit); > -- > 2.4.3