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firmware: introduce sysfs driver for QEMU's fw_cfg device
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 <somlo@cmu.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Gabriel Somlo
Greg Kroah-Hartman
parent
2fe829aca9
commit
75f3e8e47f
58
Documentation/ABI/testing/sysfs-firmware-qemu_fw_cfg
Normal file
58
Documentation/ABI/testing/sysfs-firmware-qemu_fw_cfg
Normal file
@ -0,0 +1,58 @@
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What: /sys/firmware/qemu_fw_cfg/
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Date: August 2015
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Contact: Gabriel Somlo <somlo@cmu.edu>
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Description:
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Several different architectures supported by QEMU (x86, arm,
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sun4*, ppc/mac) are provisioned with a firmware configuration
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(fw_cfg) device, originally intended as a way for the host to
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provide configuration data to the guest firmware. Starting
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with QEMU v2.4, arbitrary fw_cfg file entries may be specified
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by the user on the command line, which makes fw_cfg additionally
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useful as an out-of-band, asynchronous mechanism for providing
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configuration data to the guest userspace.
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The authoritative guest-side hardware interface documentation
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to the fw_cfg device can be found in "docs/specs/fw_cfg.txt"
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in the QEMU source tree.
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=== SysFS fw_cfg Interface ===
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The fw_cfg sysfs interface described in this document is only
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intended to display discoverable blobs (i.e., those registered
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with the file directory), as there is no way to determine the
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presence or size of "legacy" blobs (with selector keys between
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0x0002 and 0x0018) programmatically.
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All fw_cfg information is shown under:
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/sys/firmware/qemu_fw_cfg/
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The only legacy blob displayed is the fw_cfg device revision:
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/sys/firmware/qemu_fw_cfg/rev
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--- Discoverable fw_cfg blobs by selector key ---
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All discoverable blobs listed in the fw_cfg file directory are
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displayed as entries named after their unique selector key
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value, e.g.:
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/sys/firmware/qemu_fw_cfg/by_key/32
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/sys/firmware/qemu_fw_cfg/by_key/33
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/sys/firmware/qemu_fw_cfg/by_key/34
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...
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Each such fw_cfg sysfs entry has the following values exported
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as attributes:
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name : The 56-byte nul-terminated ASCII string used as the
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blob's 'file name' in the fw_cfg directory.
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size : The length of the blob, as given in the fw_cfg
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directory.
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key : The value of the blob's selector key as given in the
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fw_cfg directory. This value is the same as used in
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the parent directory name.
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raw : The raw bytes of the blob, obtained by selecting the
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entry via the control register, and reading a number
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of bytes equal to the blob size from the data
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register.
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@ -161,6 +161,25 @@ config RASPBERRYPI_FIRMWARE
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This option enables support for communicating with the firmware on the
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Raspberry Pi.
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config FW_CFG_SYSFS
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tristate "QEMU fw_cfg device support in sysfs"
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depends on SYSFS && (ARM || ARM64 || PPC_PMAC || SPARC || X86)
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default n
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help
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Say Y or M here to enable the exporting of the QEMU firmware
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configuration (fw_cfg) file entries via sysfs. Entries are
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found under /sys/firmware/fw_cfg when this option is enabled
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and loaded.
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config FW_CFG_SYSFS_CMDLINE
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bool "QEMU fw_cfg device parameter parsing"
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depends on FW_CFG_SYSFS
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help
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Allow the qemu_fw_cfg device to be initialized via the kernel
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command line or using a module parameter.
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WARNING: Using incorrect parameters (base address in particular)
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may crash your system.
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config QCOM_SCM
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bool
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depends on ARM || ARM64
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@ -14,6 +14,7 @@ obj-$(CONFIG_ISCSI_IBFT_FIND) += iscsi_ibft_find.o
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obj-$(CONFIG_ISCSI_IBFT) += iscsi_ibft.o
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obj-$(CONFIG_FIRMWARE_MEMMAP) += memmap.o
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obj-$(CONFIG_RASPBERRYPI_FIRMWARE) += raspberrypi.o
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obj-$(CONFIG_FW_CFG_SYSFS) += qemu_fw_cfg.o
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obj-$(CONFIG_QCOM_SCM) += qcom_scm.o
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obj-$(CONFIG_QCOM_SCM_64) += qcom_scm-64.o
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obj-$(CONFIG_QCOM_SCM_32) += qcom_scm-32.o
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648
drivers/firmware/qemu_fw_cfg.c
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648
drivers/firmware/qemu_fw_cfg.c
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@ -0,0 +1,648 @@
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/*
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* drivers/firmware/qemu_fw_cfg.c
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*
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* Copyright 2015 Carnegie Mellon University
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*
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* Expose entries from QEMU's firmware configuration (fw_cfg) device in
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* sysfs (read-only, under "/sys/firmware/qemu_fw_cfg/...").
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*
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* The fw_cfg device may be instantiated via either an ACPI node (on x86
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* and select subsets of aarch64), a Device Tree node (on arm), or using
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* a kernel module (or command line) parameter with the following syntax:
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*
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* [fw_cfg.]ioport=<size>@<base>[:<ctrl_off>:<data_off>]
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* or
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* [fw_cfg.]mmio=<size>@<base>[:<ctrl_off>:<data_off>]
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*
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* where:
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* <size> := size of ioport or mmio range
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* <base> := physical base address of ioport or mmio range
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* <ctrl_off> := (optional) offset of control register
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* <data_off> := (optional) offset of data register
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*
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* e.g.:
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* fw_cfg.ioport=2@0x510:0:1 (the default on x86)
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* or
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* fw_cfg.mmio=0xA@0x9020000:8:0 (the default on arm)
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*/
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/acpi.h>
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#include <linux/slab.h>
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#include <linux/io.h>
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#include <linux/ioport.h>
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MODULE_AUTHOR("Gabriel L. Somlo <somlo@cmu.edu>");
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MODULE_DESCRIPTION("QEMU fw_cfg sysfs support");
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MODULE_LICENSE("GPL");
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/* selector key values for "well-known" fw_cfg entries */
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#define FW_CFG_SIGNATURE 0x00
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#define FW_CFG_ID 0x01
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#define FW_CFG_FILE_DIR 0x19
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/* size in bytes of fw_cfg signature */
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#define FW_CFG_SIG_SIZE 4
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/* fw_cfg "file name" is up to 56 characters (including terminating nul) */
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#define FW_CFG_MAX_FILE_PATH 56
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/* fw_cfg file directory entry type */
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struct fw_cfg_file {
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u32 size;
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u16 select;
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u16 reserved;
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char name[FW_CFG_MAX_FILE_PATH];
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};
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/* fw_cfg device i/o register addresses */
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static bool fw_cfg_is_mmio;
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static phys_addr_t fw_cfg_p_base;
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static resource_size_t fw_cfg_p_size;
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static void __iomem *fw_cfg_dev_base;
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static void __iomem *fw_cfg_reg_ctrl;
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static void __iomem *fw_cfg_reg_data;
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/* atomic access to fw_cfg device (potentially slow i/o, so using mutex) */
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static DEFINE_MUTEX(fw_cfg_dev_lock);
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/* pick appropriate endianness for selector key */
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static inline u16 fw_cfg_sel_endianness(u16 key)
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{
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return fw_cfg_is_mmio ? cpu_to_be16(key) : cpu_to_le16(key);
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}
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/* read chunk of given fw_cfg blob (caller responsible for sanity-check) */
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static inline void fw_cfg_read_blob(u16 key,
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void *buf, loff_t pos, size_t count)
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{
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mutex_lock(&fw_cfg_dev_lock);
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iowrite16(fw_cfg_sel_endianness(key), fw_cfg_reg_ctrl);
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while (pos-- > 0)
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ioread8(fw_cfg_reg_data);
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ioread8_rep(fw_cfg_reg_data, buf, count);
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mutex_unlock(&fw_cfg_dev_lock);
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}
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/* clean up fw_cfg device i/o */
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static void fw_cfg_io_cleanup(void)
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{
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if (fw_cfg_is_mmio) {
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iounmap(fw_cfg_dev_base);
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release_mem_region(fw_cfg_p_base, fw_cfg_p_size);
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} else {
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ioport_unmap(fw_cfg_dev_base);
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release_region(fw_cfg_p_base, fw_cfg_p_size);
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}
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}
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/* arch-specific ctrl & data register offsets are not available in ACPI, DT */
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#if !(defined(FW_CFG_CTRL_OFF) && defined(FW_CTRL_DATA_OFF))
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# if (defined(CONFIG_ARM) || defined(CONFIG_ARM64))
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# define FW_CFG_CTRL_OFF 0x08
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# define FW_CFG_DATA_OFF 0x00
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# elif (defined(CONFIG_PPC_PMAC) || defined(CONFIG_SPARC32)) /* ppc/mac,sun4m */
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# define FW_CFG_CTRL_OFF 0x00
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# define FW_CFG_DATA_OFF 0x02
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# elif (defined(CONFIG_X86) || defined(CONFIG_SPARC64)) /* x86, sun4u */
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# define FW_CFG_CTRL_OFF 0x00
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# define FW_CFG_DATA_OFF 0x01
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# else
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# warning "QEMU FW_CFG may not be available on this architecture!"
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# define FW_CFG_CTRL_OFF 0x00
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# define FW_CFG_DATA_OFF 0x01
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# endif
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#endif
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/* initialize fw_cfg device i/o from platform data */
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static int fw_cfg_do_platform_probe(struct platform_device *pdev)
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{
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char sig[FW_CFG_SIG_SIZE];
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struct resource *range, *ctrl, *data;
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/* acquire i/o range details */
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fw_cfg_is_mmio = false;
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range = platform_get_resource(pdev, IORESOURCE_IO, 0);
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if (!range) {
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fw_cfg_is_mmio = true;
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range = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!range)
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return -EINVAL;
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}
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fw_cfg_p_base = range->start;
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fw_cfg_p_size = resource_size(range);
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if (fw_cfg_is_mmio) {
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if (!request_mem_region(fw_cfg_p_base,
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fw_cfg_p_size, "fw_cfg_mem"))
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return -EBUSY;
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fw_cfg_dev_base = ioremap(fw_cfg_p_base, fw_cfg_p_size);
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if (!fw_cfg_dev_base) {
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release_mem_region(fw_cfg_p_base, fw_cfg_p_size);
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return -EFAULT;
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}
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} else {
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if (!request_region(fw_cfg_p_base,
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fw_cfg_p_size, "fw_cfg_io"))
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return -EBUSY;
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fw_cfg_dev_base = ioport_map(fw_cfg_p_base, fw_cfg_p_size);
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if (!fw_cfg_dev_base) {
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release_region(fw_cfg_p_base, fw_cfg_p_size);
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return -EFAULT;
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}
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}
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/* were custom register offsets provided (e.g. on the command line)? */
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ctrl = platform_get_resource_byname(pdev, IORESOURCE_REG, "ctrl");
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data = platform_get_resource_byname(pdev, IORESOURCE_REG, "data");
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if (ctrl && data) {
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fw_cfg_reg_ctrl = fw_cfg_dev_base + ctrl->start;
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fw_cfg_reg_data = fw_cfg_dev_base + data->start;
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} else {
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/* use architecture-specific offsets */
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fw_cfg_reg_ctrl = fw_cfg_dev_base + FW_CFG_CTRL_OFF;
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fw_cfg_reg_data = fw_cfg_dev_base + FW_CFG_DATA_OFF;
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}
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/* verify fw_cfg device signature */
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fw_cfg_read_blob(FW_CFG_SIGNATURE, sig, 0, FW_CFG_SIG_SIZE);
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if (memcmp(sig, "QEMU", FW_CFG_SIG_SIZE) != 0) {
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fw_cfg_io_cleanup();
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return -ENODEV;
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}
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return 0;
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}
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/* fw_cfg revision attribute, in /sys/firmware/qemu_fw_cfg top-level dir. */
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static u32 fw_cfg_rev;
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static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf)
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{
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return sprintf(buf, "%u\n", fw_cfg_rev);
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}
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static const struct {
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struct attribute attr;
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ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf);
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} fw_cfg_rev_attr = {
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.attr = { .name = "rev", .mode = S_IRUSR },
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.show = fw_cfg_showrev,
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};
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/* fw_cfg_sysfs_entry type */
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struct fw_cfg_sysfs_entry {
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struct kobject kobj;
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struct fw_cfg_file f;
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struct list_head list;
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};
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/* get fw_cfg_sysfs_entry from kobject member */
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static inline struct fw_cfg_sysfs_entry *to_entry(struct kobject *kobj)
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{
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return container_of(kobj, struct fw_cfg_sysfs_entry, kobj);
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}
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/* fw_cfg_sysfs_attribute type */
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struct fw_cfg_sysfs_attribute {
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struct attribute attr;
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ssize_t (*show)(struct fw_cfg_sysfs_entry *entry, char *buf);
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};
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/* get fw_cfg_sysfs_attribute from attribute member */
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static inline struct fw_cfg_sysfs_attribute *to_attr(struct attribute *attr)
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{
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return container_of(attr, struct fw_cfg_sysfs_attribute, attr);
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}
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/* global cache of fw_cfg_sysfs_entry objects */
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static LIST_HEAD(fw_cfg_entry_cache);
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/* kobjects removed lazily by kernel, mutual exclusion needed */
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static DEFINE_SPINLOCK(fw_cfg_cache_lock);
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static inline void fw_cfg_sysfs_cache_enlist(struct fw_cfg_sysfs_entry *entry)
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{
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spin_lock(&fw_cfg_cache_lock);
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list_add_tail(&entry->list, &fw_cfg_entry_cache);
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spin_unlock(&fw_cfg_cache_lock);
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}
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static inline void fw_cfg_sysfs_cache_delist(struct fw_cfg_sysfs_entry *entry)
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{
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spin_lock(&fw_cfg_cache_lock);
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list_del(&entry->list);
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spin_unlock(&fw_cfg_cache_lock);
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}
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static void fw_cfg_sysfs_cache_cleanup(void)
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{
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struct fw_cfg_sysfs_entry *entry, *next;
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list_for_each_entry_safe(entry, next, &fw_cfg_entry_cache, list) {
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/* will end up invoking fw_cfg_sysfs_cache_delist()
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* via each object's release() method (i.e. destructor)
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*/
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kobject_put(&entry->kobj);
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}
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}
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/* default_attrs: per-entry attributes and show methods */
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#define FW_CFG_SYSFS_ATTR(_attr) \
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struct fw_cfg_sysfs_attribute fw_cfg_sysfs_attr_##_attr = { \
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.attr = { .name = __stringify(_attr), .mode = S_IRUSR }, \
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.show = fw_cfg_sysfs_show_##_attr, \
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}
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static ssize_t fw_cfg_sysfs_show_size(struct fw_cfg_sysfs_entry *e, char *buf)
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{
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return sprintf(buf, "%u\n", e->f.size);
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}
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static ssize_t fw_cfg_sysfs_show_key(struct fw_cfg_sysfs_entry *e, char *buf)
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{
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return sprintf(buf, "%u\n", e->f.select);
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}
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static ssize_t fw_cfg_sysfs_show_name(struct fw_cfg_sysfs_entry *e, char *buf)
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{
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return sprintf(buf, "%s\n", e->f.name);
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}
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static FW_CFG_SYSFS_ATTR(size);
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static FW_CFG_SYSFS_ATTR(key);
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static FW_CFG_SYSFS_ATTR(name);
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static struct attribute *fw_cfg_sysfs_entry_attrs[] = {
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&fw_cfg_sysfs_attr_size.attr,
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&fw_cfg_sysfs_attr_key.attr,
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&fw_cfg_sysfs_attr_name.attr,
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NULL,
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};
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/* sysfs_ops: find fw_cfg_[entry, attribute] and call appropriate show method */
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static ssize_t fw_cfg_sysfs_attr_show(struct kobject *kobj, struct attribute *a,
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char *buf)
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{
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struct fw_cfg_sysfs_entry *entry = to_entry(kobj);
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struct fw_cfg_sysfs_attribute *attr = to_attr(a);
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return attr->show(entry, buf);
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}
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static const struct sysfs_ops fw_cfg_sysfs_attr_ops = {
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.show = fw_cfg_sysfs_attr_show,
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};
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/* release: destructor, to be called via kobject_put() */
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static void fw_cfg_sysfs_release_entry(struct kobject *kobj)
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{
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struct fw_cfg_sysfs_entry *entry = to_entry(kobj);
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fw_cfg_sysfs_cache_delist(entry);
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kfree(entry);
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}
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/* kobj_type: ties together all properties required to register an entry */
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static struct kobj_type fw_cfg_sysfs_entry_ktype = {
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.default_attrs = fw_cfg_sysfs_entry_attrs,
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.sysfs_ops = &fw_cfg_sysfs_attr_ops,
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.release = fw_cfg_sysfs_release_entry,
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};
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/* raw-read method and attribute */
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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 "<size>" portion of command line argument */
|
||||
size = memparse(arg, &str);
|
||||
|
||||
/* get "@<base>[:<ctrl_off>:<data_off>]" chunks */
|
||||
processed = sscanf(str, PH_ADDR_SCAN_FMT,
|
||||
&base, &consumed,
|
||||
&ctrl_off, &data_off, &consumed);
|
||||
|
||||
/* sscanf() must process precisely 1 or 3 chunks:
|
||||
* <base> is mandatory, optionally followed by <ctrl_off>
|
||||
* and <data_off>;
|
||||
* 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);
|
||||
Loading…
Reference in New Issue
Block a user