[U-Boot-Users] pci_hose_write_config_{byte,word}_via_dword?

[Masami Komiya]

I have confirmed the problem reported in this list.

When pci_hose_write_config_{byte,word}_via_dword is used
the upper byte is destroied.

If you can access pci device, please execute pci command
as the followings.

# pci w.l 00.0c.00 10 12345600
# pci display 00.0c.00 10
00000010: 12345601 10000000 00000000 00000000

# pci w.b 00.0c.00 13 ff
# pci display 00.0c.00 10
00000010: ff345601 10000000 00000000 00000000 <== GOOD

-----------------------------------------------------------

# pci w.l 00.0c.00 10 12345600
# pci display 00.0c.00 10
00000010: 12345601 10000000 00000000 00000000

# pci w.b 00.0c.00 12 ff
# pci display 00.0c.00 10
00000010: 00ff5601 10000000 00000000 00000000 <== NG

-----------------------------------------------------------

# pci w.l 00.0c.00 10 12345600
# pci display 00.0c.00 10
00000010: 12345601 10000000 00000000 00000000

# pci w.b 00.0c.00 11 ff
# pci display 00.0c.00 10
00000010: 0034ff01 10000000 00000000 00000000 <== NG

-----------------------------------------------------------

# pci w.l 00.0c.00 10 12345600
# pci display 00.0c.00 10
00000010: 12345601 10000000 00000000 00000000

# pci w.w 00.0c.00 10 ffff
# pci display 00.0c.00 10
00000010: 0000ff01 10000000 00000000 00000000 <== NG

How is your result ?

Best regards.

Masami Komiya


Masao Uebayashi wrote:
> Hello.
> 
> Is there anyone successfully using
> pci_hose_write_config_{byte,word}_via_dword defined as a macro in
> drivers/pci.c?  Or, are you sure what the code there is doing?  When I
> tried to use it, writing a byte failed and I used the following code.
> 
> I think the current code is just wrong, but I can't explain how it's
> wrong since I can't understand the intention of the code. :-)
> 
> Masao
> 
> #define	__mask(_o, _v)							\
> 	(_v << ((offset & _o) * 8))
> 
> #define	__data(_o, _v)							\
> 	((((unsigned long)(val)) & _v) << ((offset & _o) * 8))
> 
> #define PCI_WRITE_VIA_DWORD_OP(__size, __type, __offsetmask, __valmask)	\
> int pci_hose_write_config_##__size##_via_dword(				\
> 	struct pci_controller *hose,					\
> 	pci_dev_t dev,							\
> 	int offset,							\
> 	__type val)							\
> {									\
> 	u32 val32;							\
> 									\
> 	if (pci_hose_read_config_dword(hose, dev, offset & ~0x3, &val32) < 0) \
> 		return -1;						\
> 	/* Clear a byte/word in a word. */				\
> 	val32 &= ~__mask(__offsetmask, __valmask);			\
> 	/* Fill a cleared byte/word in a word with a byte/word value. */ \
> 	val32 |= __data(__offsetmask, __valmask);			\
> 	/* Write the value as a word! */				\
> 	if (pci_hose_write_config_dword(hose, dev, offset & ~0x3, val32) < 0) \
> 		return -1;						\
> 									\
> 	return 0;							\
> }
> 
> 
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