Hi 2011/11/23 Gabor Juhos <juhosg@xxxxxxxxxxx>: > Hi René, > >> I don't know on which board you tested the patches, > > The patches were tested on an Ubiquiti Bullet 5M (AR7240), on a > TP-Link TL-MR3420 (AR7241), and on an Atheros PB44 (AR7161) boards. > You can find the bootlog of the Bullet 5M here: > http://pastebin.com/p3UiU29M > >> but the pci read/write function are now broken. > > Here is a snippet from the original pci_read function: > > switch (size) { > case 1: > addr = where & ~3; > mask = 0xff000000 >> ((where % 4) * 8); > tval = reg_read(ATH724X_PCI_DEV_BASE + addr); > tval = tval & ~mask; > *value = (tval >> ((4 - (where % 4))*8)); > break; > > Say, we want to read four values from where={0,1,2,3} and with size=1. > Because 'addr' will be zero, we will read the same 32 bits wide register > in all cases, so I'm using 'tval = 0x12345678' for simplicity. > > if where == 0: > > mask = 0xff000000 >> ((0 % 4) * 8) = 0xff000000 >> (0 * 8) = 0xff000000 >> 0 = 0xff000000 > tval = 0x12345678 & ~0xff000000 = 0x12345678 & 0x00ffffff = 0x00345678 > *value = 0x00345678 >> ((4 - (0 % 4 )) * 8) = 0x00345678 >> ((4 - 0) * 8) = 0x00345678 >> (4 * 8) = 0x00345678 >> 32 = 0x00000000 > > Because shift is 32, the CPU will do nothing with the value, so it will > return '0x00345678'. The value should be '0x78'. > > if where == 1: > > mask = 0xff000000 >> ((1 % 4) * 8) = 0xff000000 >> (1 * 8) = 0xff000000 >> 8 = 0x00ff0000 > tval = 0x12345678 & ~0x00ff0000 = 0x12345678 & 0xff00ffff = 0x12005678 > *value = 0x12005678 >> ((4 - (1 % 4 )) * 8) = 0x12005678 >> ((4 - 1) * 8) = 0x12005678 >> (3 * 8) = 0x12005678 >> 24 = 0x00000012 > > The value should be '0x56' instead of '0x00000012'. > > if where = 2: > > mask = 0xff000000 >> ((2 % 4) * 8) = 0xff000000 >> (2 * 8) = 0xff000000 >> 16 = 0x0000ff00 > tval = 0x12345678 & ~0x0000ff00 = 0x12345678 & 0xffff00ff = 0x12340078 > *value = 0x12340078 >> ((4 - (2 % 4 )) * 8) = 0x12340078 >> ((4 - 2) * 8) = 0x12340078 >> (2 * 8) = 0x12340078 >> 16 = 0x00001234 > > The value should be '0x34' instead of '0x00001234'. > > if where = 3: > > mask = 0xff000000 >> ((3 % 4) * 8) = 0xff000000 >> (3 * 8) = 0xff000000 >> 24 = 0x000000ff > tval = 0x12345678 & ~0x000000ff = 0x12345678 & 0xffffff00 = 0x12345600 > *value = 0x12345600 >> ((4 - (3 % 4 )) * 8) = 0x12345600 >> ((4 - 3) * 8) = 0x12345600 >> (1 * 8) = 0x12345600 >> 8 = 0x00123456 > > The value should be '0x12' instead of '0x00123456'. > > Due to this, and the other errors in the pci_write functions, > Linux fails to assign the correct IRQ number for the device. > It can be noticed from the output of 'lspci -vv': > > Interrupt: pin A routed to IRQ 0 > vs > Interrupt: pin A routed to IRQ 48 > > I can show you the errors in the write functions, if you would > like to see that as well. > > > I'm curious why do you think that it is broken now. > You are getting a data bus error by any chance? > after a pci write, the pci read return bogus values. However, I go through this tomorrow. >> -My patchset has the ability to use different irqs (see pci_data). > > Yes, I know. You can set that from the board setup by calling the > {ath,ar}724x_pci_add_data function. > > However that approach has some limitations: > > 1. It does not supports assigning a different IRQ for the different > interrupt pins (A,B,C,D) of a PCI device. This is not a problem on the > AR724X boards, but that functionality is needed by some AR71xx based > boards. > > 2. The devfn field of the struct pci_device is 0 on the AR724X based boards. > However on AR71XX they are different. On the PB44 board, the devfn of a PCI > device in the first miniPCI slot is 136, and it is 144 for the second slot. > So if I want to define the pci_data for the PB44 board, I should write > something like this: > > static struct ath724x_pci_data pb44_pci_data[] = { > [136] = { .irq = PCI_IRQ_A }, > [144] = { .irq = PCI_IRQ_B }, > }; > > The array has 136+8 unused entries, which wastes the memory. > > 3. The {ath,ar}724x_pci_add_data function must be called from the > setup code of each board. If the board setup code does not calls the > function, the kernel will throw an oops due to a NULL pointer dereference. > >> int __init pcibios_map_irq(const struct pci_dev *dev, uint8_t slot, uint8_t pin) >> { >> unsigned int devfn = dev->devfn; >> int irq = -1; >> > > If the '{ath,ar}724x_pci_add_data' function is not called, pci_data_size = 0, > and pci_data = NULL; > >> if (devfn > pci_data_size - 1) >> return irq; > > devfn is always >= 0, and (pci_data_size - 1) = -1 = 0xffffffff, so the > condition in this if statement will be evaluated to false ... > >> irq = pci_data[devfn].irq; > > ... and this line will cause the following oops: > > CPU 0 Unable to handle kernel paging request at virtual address 00000000, epc == 803c4cc8, ra == 803c4ca4 > Oops[#1]: > Cpu 0 > $ 0 : 00000000 80510000 00000000 00000000 > $ 4 : 803b4128 00000a52 ffffffff 0000000a > $ 8 : 0000000a 00000000 00000001 00000000 > $12 : 00000374 0000000f 00000001 ffffffff > $16 : 00000000 80510000 803c4c74 8019d838 > $20 : 803d3fe0 00000000 00000000 00000000 > $24 : 00000002 800617f0 > $28 : 81c20000 81c21e50 00000000 803c4ca4 > Hi : 00000000 > Lo : 068e7780 > epc : 803c4cc8 pcibios_map_irq+0x54/0x6c > Not tainted > ra : 803c4ca4 pcibios_map_irq+0x30/0x6c > Status: 1000c003 KERNEL EXL IE > Cause : 00800008 > BadVA : 00000000 > PrId : 00019374 (MIPS 24Kc) > Modules linked in: > Process swapper (pid: 1, threadinfo=81c20000, task=81c18000, tls=00000000) > Stack : 81c21e58 00000000 ffffffff 00000001 00000000 81c14c00 00000001 803d1840 > 00000000 80300ce8 803d2a7c 00000000 01000000 803d2af8 81c46800 00000000 > 803e9584 00000000 80510000 803d404c 00000000 00000000 80510000 803e9584 > 80510000 80060930 33390000 00000000 0000a498 80143058 00000028 803b0000 > 00000000 800bc4e4 803e92d0 803e9394 803e9584 00000000 00000000 00000000 > ... > Call Trace: > [<803c4cc8>] pcibios_map_irq+0x54/0x6c > [<803d1840>] pci_fixup_irqs+0x78/0xc4 > [<803d404c>] pcibios_init+0x6c/0x8c > [<80060930>] do_one_initcall+0x3c/0x1cc > [<803c297c>] kernel_init+0xa4/0x138 > [<80063c44>] kernel_thread_helper+0x10/0x18 > > Code: 8c4250b4 001080c0 00508021 <8e020000> 8fbf001c 8fb10018 8fb00014 03e00008 27bd0020 > >> >> return irq; >> } Ok >> -I never hit the pci controller bug, any steps to replicate? > > Hm, weird. Your devices are based on AR7240 or or AR7241? > > Regards, > Gabor > AR7241 AH-4A Maybe it is better to split ar71xx and ar72xx pci support completly?
