Hi Fabio,
On 9 October 2015 at 14:22, Fabio Estevam festevam@gmail.com wrote:
Hi Simon,
On Fri, Oct 9, 2015 at 10:01 AM, Simon Glass sjg@chromium.org wrote:
I'm just surprised that it is failing when there is nothing there. I think it should succeed (and read 0xffff).
What board is this? Can you find the code that is returning this error? It may be a call to pci_set_ops() which sets read_word().
It is a mx6qsabresd board.
I don't have the PCI device at the moment to give it a try, but looking at the code, in pcie_imx we have:
pci_set_ops(hose, pci_hose_read_config_byte_via_dword, pci_hose_read_config_word_via_dword, imx_pcie_read_config, pci_hose_write_config_byte_via_dword, pci_hose_write_config_word_via_dword, imx_pcie_write_config);Then in drivers/pci/pci.c:
#define PCI_READ_VIA_DWORD_OP(size, type, off_mask) \ int pci_hose_read_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 & 0xfc, &val32) < 0) { \ *val = -1; \ return -1; \ } \ \ *val = (val32 >> ((offset & (int)off_mask) * 8)); \ \ return 0; \ }
,which returns -1 (and also *val = -1) in the case of errror, which matches the values that I was reading yesterday
If you look down one more level, these end up calling imx_pcie_read_config() which calls imx_pcie_addr_valid():
static int imx_pcie_addr_valid(pci_dev_t d) { if ((PCI_BUS(d) == 0) && (PCI_DEV(d) > 1)) return -EINVAL; if ((PCI_BUS(d) == 1) && (PCI_DEV(d) > 0)) return -EINVAL; return 0; }
I can understand the bus check, but why return an access error if the device does not exist on the bus? That seems like a bug to me.
Regards, Simon