[PATCH v3 1/4] firmware: introduce sysfs driver for QEMU's fw_cfg device

[kbuild test robot]

Hi Gabriel,

[auto build test results on v4.3-rc3 -- if it's inappropriate base, please ignore]

reproduce:
        # apt-get install sparse
        make ARCH=x86_64 allmodconfig
        make C=1 CF=-D__CHECK_ENDIAN__


sparse warnings: (new ones prefixed by >>)

   drivers/firmware/qemu_fw_cfg.c:66:25: sparse: constant 0xd00000510 is so big it is long
>> drivers/firmware/qemu_fw_cfg.c:95:39: sparse: restricted __be16 degrades to integer
>> drivers/firmware/qemu_fw_cfg.c:95:58: sparse: restricted __le16 degrades to integer
>> drivers/firmware/qemu_fw_cfg.c:111:25: sparse: cast to restricted __be32
>> drivers/firmware/qemu_fw_cfg.c:111:25: sparse: cast to restricted __be32
>> drivers/firmware/qemu_fw_cfg.c:111:25: sparse: cast to restricted __be32
>> drivers/firmware/qemu_fw_cfg.c:111:25: sparse: cast to restricted __be32
>> drivers/firmware/qemu_fw_cfg.c:111:25: sparse: cast to restricted __be32
>> drivers/firmware/qemu_fw_cfg.c:111:25: sparse: cast to restricted __be32
>> drivers/firmware/qemu_fw_cfg.c:95:39: sparse: restricted __be16 degrades to integer
>> drivers/firmware/qemu_fw_cfg.c:95:58: sparse: restricted __le16 degrades to integer
>> drivers/firmware/qemu_fw_cfg.c:95:39: sparse: restricted __be16 degrades to integer
>> drivers/firmware/qemu_fw_cfg.c:95:58: sparse: restricted __le16 degrades to integer
   drivers/firmware/qemu_fw_cfg.c:367:25: sparse: cast to restricted __be32
   drivers/firmware/qemu_fw_cfg.c:367:25: sparse: cast to restricted __be32
   drivers/firmware/qemu_fw_cfg.c:367:25: sparse: cast to restricted __be32
   drivers/firmware/qemu_fw_cfg.c:367:25: sparse: cast to restricted __be32
   drivers/firmware/qemu_fw_cfg.c:367:25: sparse: cast to restricted __be32
   drivers/firmware/qemu_fw_cfg.c:367:25: sparse: cast to restricted __be32
>> drivers/firmware/qemu_fw_cfg.c:368:27: sparse: cast to restricted __be16
>> drivers/firmware/qemu_fw_cfg.c:368:27: sparse: cast to restricted __be16
>> drivers/firmware/qemu_fw_cfg.c:368:27: sparse: cast to restricted __be16
>> drivers/firmware/qemu_fw_cfg.c:368:27: sparse: cast to restricted __be16
>> drivers/firmware/qemu_fw_cfg.c:95:39: sparse: restricted __be16 degrades to integer
>> drivers/firmware/qemu_fw_cfg.c:95:58: sparse: restricted __le16 degrades to integer
>> drivers/firmware/qemu_fw_cfg.c:420:22: sparse: cast to restricted __le32

vim +95 drivers/firmware/qemu_fw_cfg.c

    60			.size = 0x0a,
    61			.ctrl_offset = 0x08,
    62			.data_offset = 0x00,
    63			.is_mmio = true,
    64		}, {
    65			.name = "fw_cfg MMIO on sun4m",
  > 66			.base = 0xd00000510,
    67			.size = 0x03,
    68			.ctrl_offset = 0x00,
    69			.data_offset = 0x02,
    70			.is_mmio = true,
    71		}, {
    72			.name = "fw_cfg MMIO on ppc/mac",
    73			.base = 0xf0000510,
    74			.size = 0x03,
    75			.ctrl_offset = 0x00,
    76			.data_offset = 0x02,
    77			.is_mmio = true,
    78		}, { } /* END */
    79	};
    80	
    81	/* fw_cfg device i/o currently selected option set */
    82	static struct fw_cfg_access *fw_cfg_mode;
    83	
    84	/* fw_cfg device i/o register addresses */
    85	static void __iomem *fw_cfg_dev_base;
    86	static void __iomem *fw_cfg_reg_ctrl;
    87	static void __iomem *fw_cfg_reg_data;
    88	
    89	/* atomic access to fw_cfg device (potentially slow i/o, so using mutex) */
    90	static DEFINE_MUTEX(fw_cfg_dev_lock);
    91	
    92	/* pick appropriate endianness for selector key */
    93	static inline u16 fw_cfg_sel_endianness(u16 key)
    94	{
  > 95		return fw_cfg_mode->is_mmio ? cpu_to_be16(key) : cpu_to_le16(key);
    96	}
    97	
    98	/* type for fw_cfg "directory scan" visitor/callback function */
    99	typedef int (*fw_cfg_file_callback)(const struct fw_cfg_file *f);
   100	
   101	/* run a given callback on each fw_cfg directory entry */
   102	static int fw_cfg_scan_dir(fw_cfg_file_callback callback)
   103	{
   104		int ret = 0;
   105		u32 count, i;
   106		struct fw_cfg_file f;
   107	
   108		mutex_lock(&fw_cfg_dev_lock);
   109		iowrite16(fw_cfg_sel_endianness(FW_CFG_FILE_DIR), fw_cfg_reg_ctrl);
   110		ioread8_rep(fw_cfg_reg_data, &count, sizeof(count));
 > 111		for (i = 0; i < be32_to_cpu(count); i++) {
   112			ioread8_rep(fw_cfg_reg_data, &f, sizeof(f));
   113			ret = callback(&f);
   114			if (ret)

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