phy_scan_fixups()

Source: http://lists.openwall.net/netdev/2008/04/09/53

+Board Fixups
+
+ Sometimes the specific interaction between the platform and the PHY requires
+ special handling.  For instance, to change where the PHY's clock input is,
+ or to add a delay to account for latency issues in the data path.  In order
+ to support such contingencies, the PHY Layer allows platform code to register
+ fixups to be run when the PHY is brought up (or subsequently reset).
+ 
+ When the PHY Layer brings up a PHY it checks to see if there are any fixups
+ registered for it, matching based on UID (contained in the PHY device's phy_id
+ field) and the bus identifier (contained in phydev->dev.bus_id).  Both must
+ match, however two constants, PHY_ANY_ID and PHY_ANY_UID, are provided as
+ wildcards for the bus ID and UID, respectively.
+ 
+ When a match is found, the PHY layer will invoke the run function associated
+ with the fixup.  This function is passed a pointer to the phy_device of
+ interest.  It should therefore only operate on that PHY.
+ 
+ The platform code can either register the fixup using phy_register_fixup():
+ 
+ int phy_register_fixup(const char *phy_id,
+  u32 phy_uid, u32 phy_uid_mask,
+  int (*run)(struct phy_device *));
+
+ Or using one of the two stubs, phy_register_fixup_for_uid() and
+ phy_register_fixup_for_id():
+ 
+ int phy_register_fixup_for_uid(u32 phy_uid, u32 phy_uid_mask,
+  int (*run)(struct phy_device *));
+ int phy_register_fixup_for_id(const char *phy_id,
+  int (*run)(struct phy_device *));
+ 
+ The stubs set one of the two matching criteria, and set the other one to
+ match anything.
+

Linux module parameters.

Source: http://nano-chicken.blogspot.tw/2011/01/linux-modules11module-parameters.html

Linux Module允許使用者在insmod時帶入相關的parameters，這些parameters必須被宣告成golbal，並且使用 module_param()宣告資料型態與權限，目前支援的資料型態有byte, short, ushort, int, uint, long, ulong, charp, bool等等。也可以使用module_param_array(name, type, num, perm)宣告成陣列。perm(權限)會決定/sys/module/顯示該參數的權限。

#include 
#include 

MODULE_LICENSE("GPL");

static unsigned char b_byte = 1;
module_param(b_byte, byte, S_IRUGO|S_IWUSR);

static short int b_short = 2;
module_param(b_short, short, S_IRUGO|S_IWUSR);

static unsigned short int b_ushort = 3;
module_param(b_ushort, ushort, S_IRUGO|S_IWUSR);

static int b_int = 6;
module_param(b_int, int, S_IRUGO|S_IWUSR);

static unsigned int b_uint = 5;
module_param(b_uint, uint, S_IRUGO|S_IWUSR);

static long b_long = 6;
module_param(b_long, long, S_IRUGO|S_IWUSR);

static unsigned long b_ulong = 7;
module_param(b_ulong, ulong, S_IRUGO|S_IWUSR);

static char *b_charp = "brook";
module_param(b_charp, charp, S_IRUGO|S_IWUSR);

static int b_bool = 1;
module_param(b_bool, bool, S_IRUGO|S_IWUSR);

static int __init init_modules(void)
{
    printk("b_byte: %d\n", b_byte);
    printk("b_short: %d\n", b_short);
    printk("b_ushort: %u\n", b_ushort);
    printk("b_int: %d\n", b_int);
    printk("b_uint: %u\n", b_uint);
    printk("b_long: %ld\n", b_long);
    printk("b_ulong: %lu\n", b_ulong);
    printk("b_charp: %s\n", b_charp);
    printk("b_bool: %d\n", b_bool);

    return 0;
}

static void __exit exit_modules(void)
{
}

module_init(init_modules);
module_exit(exit_modules);

 

Linux Programming Trouble Shooting

Q001.  Why is a kernel object (.o, .ko) not generated after compilation ?
A001. Check CONFIG_x, KConfig, and Makefile