diff options
| author | Stefan Roese | 2019-02-11 08:43:25 +0100 |
|---|---|---|
| committer | Tom Rini | 2019-03-22 12:15:20 -0400 |
| commit | 2253d648f11e844d2dcf572b3bb961e1a7a2b00b (patch) | |
| tree | 912e3893ba918df3197fd9fb4fa1833d8fb65640 | |
| parent | e63bf1b13b3a7ac610c238cc19041381e890900f (diff) | |
pci: Add comment to mention difference in DEVFN usage in U-Boot vs Linux
This patch adds a comment to the header with the PCI_foo macros related
to DEVFN to explain the difference in U-Boot vs Linux.
Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Simon Glass <sjg@chromium.org>
Cc: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
| -rw-r--r-- | include/pci.h | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/include/pci.h b/include/pci.h index 936cfe975cb..5fb212cab1a 100644 --- a/include/pci.h +++ b/include/pci.h @@ -499,9 +499,20 @@ static inline void pci_set_region(struct pci_region *reg, typedef int pci_dev_t; #define PCI_BUS(d) (((d) >> 16) & 0xff) + +/* + * Please note the difference in DEVFN usage in U-Boot vs Linux. U-Boot + * uses DEVFN in bits 15-8 but Linux instead expects DEVFN in bits 7-0. + * Please see the Linux header include/uapi/linux/pci.h for more details. + * This is relevant for the following macros: + * PCI_DEV, PCI_FUNC, PCI_DEVFN + * The U-Boot macro PCI_DEV is equivalent to the Linux PCI_SLOT version with + * the remark from above (input d in bits 15-8 instead of 7-0. + */ #define PCI_DEV(d) (((d) >> 11) & 0x1f) #define PCI_FUNC(d) (((d) >> 8) & 0x7) #define PCI_DEVFN(d, f) ((d) << 11 | (f) << 8) + #define PCI_MASK_BUS(bdf) ((bdf) & 0xffff) #define PCI_ADD_BUS(bus, devfn) (((bus) << 16) | (devfn)) #define PCI_BDF(b, d, f) ((b) << 16 | PCI_DEVFN(d, f)) |