I can't find where the definition of the function pci_bus_read_config_byte()

frisky · 06-23-2006, 05:09 AM

Hi all,
I can't find where the definition of the function pci_bus_read_config_byte() in file linux/pci.h of kernel 2.16.20. Neither as the other versions. I also searched the *.s files and can't find the prototype definition. Is it just a empty function? It seems impossible.

frisky · 06-23-2006, 05:13 AM

I will use pci_read_config_byte() to read PCI config space byte. It calls pci_bus_read_config_byte() and I can't find the function's definiton. So the problem. Can you help me ? thank you very much!

nx5000 · 06-23-2006, 05:18 AM

I use cscope to navigate through source, its more powerfull that vi ctags.

Install cscope, then go in your src root and do
cscope -R
for the kernel it takes some times (on my old machine, 30s) but its far far quicker than grep and stuffs.

Its a very good little tool, to my mind..

result for your question:
in drivers/pci/access.c

Quote:

int pci_bus_read_config_##size \
(struct pci_bus *bus, unsigned int devfn, int pos, type *value) \
{ \
int res; \
unsigned long flags; \
u32 data = 0; \
if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \
spin_lock_irqsave(&pci_lock, flags); \
res = bus->ops->read(bus, devfn, pos, len, &data); \
*value = (type)data; \
spin_unlock_irqrestore(&pci_lock, flags); \
return res; \
}

not easy to spot

jschiwal · 06-23-2006, 05:45 AM

You might try using grep.
quoted from drivers/pci/access.c:

Code:

/*
 * This interrupt-safe spinlock protects all accesses to PCI
 * configuration space.
 */

static DEFINE_SPINLOCK(pci_lock);

/*
 *  Wrappers for all PCI configuration access functions.  They just check
 *  alignment, do locking and call the low-level functions pointed to
 *  by pci_dev->ops.
 */

#define PCI_byte_BAD 0
#define PCI_word_BAD (pos & 1)
#define PCI_dword_BAD (pos & 3)

#define PCI_OP_READ(size,type,len) \
int pci_bus_read_config_##size \
        (struct pci_bus *bus, unsigned int devfn, int pos, type *value) \
{                                                                       \
        int res;                                                        \
        unsigned long flags;                                            \
        u32 data = 0;                                                   \
        if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER;       \
        spin_lock_irqsave(&pci_lock, flags);                            \
        res = bus->ops->read(bus, devfn, pos, len, &data);              \
        *value = (type)data;                                            \
        spin_unlock_irqrestore(&pci_lock, flags);                       \
        return res;                                                     \
}

nx5000 · 06-23-2006, 05:50 AM

IMHO, grep is a bit archaic for doing this

This is what cscope does:

Quote:

Find this C symbol:
Find this global definition:
Find functions called by this function:
Find functions calling this function:
Find this text string:
Change this text string:
Find this egrep pattern:
Find this file:
Find files #including this file:

frisky · 06-25-2006, 05:07 AM

nx5000,jschiwal:
Thank you both. I get it. Yes, I use SI 3.5 to search the symbols. I'm learning cscope

Thank you again.