Re: [PATCH 2/4] MIPS: pci: Add driver for MT7621 PCIe controller

From: Sergio Paracuellos
Date: Fri Jun 04 2021 - 14:45:12 EST


Hi Pali,

Thanks for your comments.

On Fri, Jun 4, 2021 at 6:55 PM Pali Rohár <pali@xxxxxxxxxx> wrote:
>
> On Wednesday 02 June 2021 14:43:53 Sergio Paracuellos wrote:
> > Hi Pali,
> >
> > On Wed, Jun 2, 2021 at 2:23 PM Pali Rohár <pali@xxxxxxxxxx> wrote:
> > >
> > > On Wednesday 02 June 2021 14:16:26 Sergio Paracuellos wrote:
> > > > Hi Pali,
> > > >
> > > > On Mon, May 31, 2021 at 4:19 PM Sergio Paracuellos
> > > > <sergio.paracuellos@xxxxxxxxx> wrote:
> > > > >
> > > > > On Mon, May 31, 2021 at 3:50 PM Pali Rohár <pali@xxxxxxxxxx> wrote:
> > > > > >
> > > > > > On Monday 31 May 2021 15:39:55 Sergio Paracuellos wrote:
> > > > > > > Hi Pali,
> > > > > > >
> > > > > > > Thanks for your comments.
> > > > > > >
> > > > > > > On Mon, May 31, 2021 at 3:14 PM Pali Rohár <pali@xxxxxxxxxx> wrote:
> > > > > > > >
> > > > > > > > On Saturday 15 May 2021 14:40:53 Sergio Paracuellos wrote:
> > > > > > > > > This patch adds a driver for the PCIe controller of MT7621 SoC.
> > > > > > > > >
> > > > > > > > > Signed-off-by: Sergio Paracuellos <sergio.paracuellos@xxxxxxxxx>
> > > > > > > > > ---
> > > > > > > > > arch/mips/pci/Makefile | 1 +
> > > > > > > > > arch/mips/pci/pci-mt7621.c | 624 +++++++++++++++++++++++++++++++++++++
> > > > > > > > > arch/mips/ralink/Kconfig | 9 +-
> > > > > > > > > 3 files changed, 633 insertions(+), 1 deletion(-)
> > > > > > > > > create mode 100644 arch/mips/pci/pci-mt7621.c
> > > > > > > > >
> > > > > > > > > diff --git a/arch/mips/pci/Makefile b/arch/mips/pci/Makefile
> > > > > > > > > index f3eecc065e5c..178c550739c4 100644
> > > > > > > > > --- a/arch/mips/pci/Makefile
> > > > > > > > > +++ b/arch/mips/pci/Makefile
> > > > > > > > > @@ -24,6 +24,7 @@ obj-$(CONFIG_PCI_AR2315) += pci-ar2315.o
> > > > > > > > > obj-$(CONFIG_SOC_AR71XX) += pci-ar71xx.o
> > > > > > > > > obj-$(CONFIG_PCI_AR724X) += pci-ar724x.o
> > > > > > > > > obj-$(CONFIG_PCI_XTALK_BRIDGE) += pci-xtalk-bridge.o
> > > > > > > > > +obj-$(CONFIG_PCI_MT7621) += pci-mt7621.o
> > > > > > > > > #
> > > > > > > > > # These are still pretty much in the old state, watch, go blind.
> > > > > > > > > #
> > > > > > > > > diff --git a/arch/mips/pci/pci-mt7621.c b/arch/mips/pci/pci-mt7621.c
> > > > > > > > > new file mode 100644
> > > > > > > > > index 000000000000..fe1945819d25
> > > > > > > > > --- /dev/null
> > > > > > > > > +++ b/arch/mips/pci/pci-mt7621.c
> > > > > > > > ...
> > > > > > > > > +static int mt7621_pcie_enable_ports(struct mt7621_pcie *pcie)
> > > > > > > > > +{
> > > > > > > > > + struct device *dev = pcie->dev;
> > > > > > > > > + struct mt7621_pcie_port *port;
> > > > > > > > > + u8 num_slots_enabled = 0;
> > > > > > > > > + u32 slot;
> > > > > > > > > + u32 val;
> > > > > > > > > + int err;
> > > > > > > > > +
> > > > > > > > > + /* Setup MEMWIN and IOWIN */
> > > > > > > > > + pcie_write(pcie, 0xffffffff, RALINK_PCI_MEMBASE);
> > > > > > > > > + pcie_write(pcie, pcie->io.start, RALINK_PCI_IOBASE);
> > > > > > > > > +
> > > > > > > > > + list_for_each_entry(port, &pcie->ports, list) {
> > > > > > > > > + if (port->enabled) {
> > > > > > > > > + err = clk_prepare_enable(port->clk);
> > > > > > > > > + if (err) {
> > > > > > > > > + dev_err(dev, "enabling clk pcie%d\n", slot);
> > > > > > > > > + return err;
> > > > > > > > > + }
> > > > > > > > > +
> > > > > > > > > + mt7621_pcie_enable_port(port);
> > > > > > > > > + dev_info(dev, "PCIE%d enabled\n", port->slot);
> > > > > > > > > + num_slots_enabled++;
> > > > > > > > > + }
> > > > > > > > > + }
> > > > > > > > > +
> > > > > > > > > + for (slot = 0; slot < num_slots_enabled; slot++) {
> > > > > > > > > + val = read_config(pcie, slot, PCI_COMMAND);
> > > > > > > > > + val |= PCI_COMMAND_MASTER;
> > > > > > > > > + write_config(pcie, slot, PCI_COMMAND, val);
> > > > > > > >
> > > > > > > > Hello! Is this part of code correct? Because it looks strange if PCIe
> > > > > > > > controller driver automatically enables PCI bus mastering, prior device
> > > > > > > > driver initialize itself.
> > > > > > > >
> > > > > > > > Moreover kernel has already function pci_set_master() for this purpose
> > > > > > > > which is used by device drivers.
> > > > > > > >
> > > > > > > > So I think this code can confuse some device drivers...
> > > > > > >
> > > > > > > I agree that we have pci_set_master() to be used in pci device driver
> > > > > > > code. Original controller driver set this bit for enabled slots. Since
> > > > > > > there is no documentation at all for the PCI in this SoC
> > > > > >
> > > > > > I see... this is really a big problem to do any driver development...
> > > > >
> > > > > For sure it is :(.
> > > > >
> > > > > >
> > > > > > > I have
> > > > > > > maintained the setting in the driver in a cleaner way. See original
> > > > > > > driver code and the setting here [0]. There is no other reason than
> > > > > > > that. I am ok with removing this from here and testing with my two
> > > > > > > devices that everything is still ok if having this setting in the pci
> > > > > > > controller driver is a real problem.
> > > > > >
> > > > > > You can run lspci -nnvv with and without PCI_COMMAND_MASTER code and
> > > > > > then compare outputs.
> > > > > >
> > > > > > Device drivers for sure enable PCI_COMMAND_MASTER at the time when it is
> > > > > > needed, so it is possible that there would be no difference in lspci
> > > > > > output.
> > > > >
> > > > > Thanks. I will take this into account when v2 is submitted after more
> > > > > review comments come :).
> > > >
> > > > I have tested to remove this and check lspci -nnvv output with and
> > > > without PCI_COMMAND_MASTER code and, as you pointed out, there is no
> > > > difference between them. Also, both boards are working without
> > > > regressions at all. So I will remove this code for next version.
> > >
> > > Perfect!
> > >
> > > > Thanks,
> > > > Sergio Paracuellos
> > > > >
> > > > > >
> > > > > > > [0]: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git/tree/drivers/staging/mt7621-pci/pci-mt7621.c?h=v4.18#n676
> > > > > > >
> > > > > > > Best regards,
> > > > > > > Sergio Paracuellos
> > > > > > > >
> > > > > > > > > + /* configure RC FTS number to 250 when it leaves L0s */
> > > > > > > > > + val = read_config(pcie, slot, PCIE_FTS_NUM);
> > > > > > > > > + val &= ~PCIE_FTS_NUM_MASK;
> > > > > > > > > + val |= PCIE_FTS_NUM_L0(0x50);
> > > > > > > > > + write_config(pcie, slot, PCIE_FTS_NUM, val);
> > >
> > > Could you look also what is doing this code (PCIE_FTS_NUM)? It is marked
> > > as MT specific register. But from this code for me it looks like that it
> > > just access config space of some device and therefore it could be some
> > > standard PCIe register. Just with hardcoded calculated offset.
>
> So based on your lspci output, there is no PCIe capability register at
> address PCIE_FTS_NUM (0x70c), right? It seems strange to trying access
> capability register outside of capability list.

This setting is also in the original driver code from mediatek SDK. See [0].
Anyway, I have tried to remove this code and test what happens with my
two boards and both of them seem to
work properly just by deleting this code.

>
> > > Could you provide output from lspci -nnvv? So other people could look at
> > > it and maybe we decode what is this code doing and if it is needed.
> >
> > # lspci -nnvv
> > 00:02.0 PCI bridge [0604]: Device [0e8d:0801] (rev 01) (prog-if 00
> > [Normal decode])
>
> Hm... Device address is 02. But in your code is:
>
> u8 num_slots_enabled = 0;
> ...
> list_for_each_entry(port, &pcie->ports, list) {
> if (port->enabled) {
> ...
> num_slots_enabled++;
> ...
> }
> }
> ...
> for (slot = 0; slot < num_slots_enabled; slot++) {
> val = read_config(pcie, slot, ...);
> ...
> write_config(pcie, slot, ...);
> }
>
> Which means that this code writes to config space of wrong device 0
> (instead of 2)! In function write_config() can be seen that second
> parameter specify device of BDF address for bus=0 and function=0.

Bridge enumeration depends on a virtual bridge register configuration.
But at the end devices connected to the bridge
are enumerated as 01:00.0, 02:00.0 and 03:00.0. So in this case the
phy used is the one for "pcie2" (00:02.0) and the device connected to
it
is 01:00.0. For example a board using all the virtual bridges will get
an output similar to:

[ 16.487166] mt7621-pci 1e140000.pcie: host bridge /pcie@1e140000 ranges:
[ 16.500627] mt7621-pci 1e140000.pcie: No bus range found for
/pcie@1e140000, using [bus 00-ff]
[ 16.518212] mt7621-pci 1e140000.pcie: MEM
0x0060000000..0x006fffffff -> 0x0000000000
[ 16.534531] mt7621-pci 1e140000.pcie: IO
0x001e160000..0x001e16ffff -> 0x0000000000
[ 16.786498] mt7621-pci 1e140000.pcie: PCIE0 enabled
[ 16.796220] mt7621-pci 1e140000.pcie: PCIE1 enabled
[ 16.805943] mt7621-pci 1e140000.pcie: PCIE2 enabled
[ 16.815664] mt7621-pci 1e140000.pcie: PCI coherence region base:
0x60000000, mask/settings: 0xf0000002
[ 16.834398] mt7621-pci 1e140000.pcie: PCI host bridge to bus 0000:00
[ 16.847098] pci_bus 0000:00: root bus resource [io 0x1e160000-0x1e16ffff]
[ 16.860806] pci_bus 0000:00: root bus resource [mem 0x60000000-0x6fffffff]
[ 16.874504] pci_bus 0000:00: root bus resource [bus 00-ff]
[ 16.885441] pci_bus 0000:00: root bus resource [mem
0x60000000-0x6fffffff] (bus address [0x00000000-0x0fffffff])
[ 16.905773] pci 0000:00:00.0: [0e8d:0801] type 01 class 0x060400
[ 16.917772] pci 0000:00:00.0: reg 0x10: [mem 0x00000000-0x7fffffff]
[ 16.930260] pci 0000:00:00.0: reg 0x14: initial BAR value 0x00000000 invalid
[ 16.944304] pci 0000:00:00.0: reg 0x14: [mem size 0x00010000]
[ 16.955841] pci 0000:00:00.0: supports D1
[ 16.963837] pci 0000:00:00.0: PME# supported from D0 D1 D3hot
[ 16.975747] pci 0000:00:01.0: [0e8d:0801] type 01 class 0x060400
[ 16.987772] pci 0000:00:01.0: reg 0x10: [mem 0x00000000-0x7fffffff]
[ 17.000273] pci 0000:00:01.0: reg 0x14: initial BAR value 0x00000000 invalid
[ 17.014311] pci 0000:00:01.0: reg 0x14: [mem size 0x00010000]
[ 17.025838] pci 0000:00:01.0: supports D1
[ 17.033828] pci 0000:00:01.0: PME# supported from D0 D1 D3hot
[ 17.045699] pci 0000:00:02.0: [0e8d:0801] type 01 class 0x060400
[ 17.057726] pci 0000:00:02.0: reg 0x10: [mem 0x00000000-0x7fffffff]
[ 17.070218] pci 0000:00:02.0: reg 0x14: initial BAR value 0x00000000 invalid
[ 17.084260] pci 0000:00:02.0: reg 0x14: [mem size 0x00010000]
[ 17.095788] pci 0000:00:02.0: supports D1
[ 17.103785] pci 0000:00:02.0: PME# supported from D0 D1 D3hot
[ 17.116598] pci 0000:00:00.0: bridge configuration invalid ([bus
00-00]), reconfiguring
[ 17.132566] pci 0000:00:01.0: bridge configuration invalid ([bus
00-00]), reconfiguring
[ 17.148514] pci 0000:00:02.0: bridge configuration invalid ([bus
00-00]), reconfiguring
[ 17.164739] pci 0000:01:00.0: [1b21:0611] type 00 class 0x010185
[ 17.176775] pci 0000:01:00.0: reg 0x10: [io 0x0000-0x0007]
[ 17.187892] pci 0000:01:00.0: reg 0x14: [io 0x0000-0x0003]
[ 17.199009] pci 0000:01:00.0: reg 0x18: [io 0x0000-0x0007]
[ 17.210130] pci 0000:01:00.0: reg 0x1c: [io 0x0000-0x0003]
[ 17.221246] pci 0000:01:00.0: reg 0x20: [io 0x0000-0x000f]
[ 17.232357] pci 0000:01:00.0: reg 0x24: initial BAR value 0x00000000 invalid
[ 17.246411] pci 0000:01:00.0: reg 0x24: [mem size 0x00000200]
[ 17.258031] pci 0000:01:00.0: 2.000 Gb/s available PCIe bandwidth,
limited by 2.5 GT/s PCIe x1 link at 0000:00:00.0 (capable of 4.000
Gb/s with 5.0 GT/s PCIe x1 link)
[ 17.317563] pci 0000:00:00.0: PCI bridge to [bus 01-ff]
[ 17.328033] pci 0000:00:00.0: bridge window [io 0x0000-0x0fff]
[ 17.340179] pci 0000:00:00.0: bridge window [mem 0x60000000-0x600fffff]
[ 17.353703] pci 0000:00:00.0: bridge window [mem
0x60000000-0x600fffff pref]
[ 17.368097] pci_bus 0000:01: busn_res: [bus 01-ff] end is updated to 01
[ 17.381550] pci 0000:02:00.0: [1b21:0611] type 00 class 0x010185
[ 17.393573] pci 0000:02:00.0: reg 0x10: [io 0x0000-0x0007]
[ 17.404694] pci 0000:02:00.0: reg 0x14: [io 0x0000-0x0003]
[ 17.415804] pci 0000:02:00.0: reg 0x18: [io 0x0000-0x0007]
[ 17.426916] pci 0000:02:00.0: reg 0x1c: [io 0x0000-0x0003]
[ 17.438040] pci 0000:02:00.0: reg 0x20: [io 0x0000-0x000f]
[ 17.449148] pci 0000:02:00.0: reg 0x24: initial BAR value 0x00000000 invalid
[ 17.463193] pci 0000:02:00.0: reg 0x24: [mem size 0x00000200]
[ 17.474803] pci 0000:02:00.0: 2.000 Gb/s available PCIe bandwidth,
limited by 2.5 GT/s PCIe x1 link at 0000:00:01.0 (capable of 4.000
Gb/s with 5.0 GT/s PCIe x1 link)
[ 17.527554] pci 0000:00:01.0: PCI bridge to [bus 02-ff]
[ 17.538014] pci 0000:00:01.0: bridge window [io 0x0000-0x0fff]
[ 17.550159] pci 0000:00:01.0: bridge window [mem 0x60000000-0x600fffff]
[ 17.563682] pci 0000:00:01.0: bridge window [mem
0x60000000-0x600fffff pref]
[ 17.578078] pci_bus 0000:02: busn_res: [bus 02-ff] end is updated to 02
[ 17.591529] pci 0000:03:00.0: [1b21:0611] type 00 class 0x010185
[ 17.603545] pci 0000:03:00.0: reg 0x10: [io 0x0000-0x0007]
[ 17.614665] pci 0000:03:00.0: reg 0x14: [io 0x0000-0x0003]
[ 17.625775] pci 0000:03:00.0: reg 0x18: [io 0x0000-0x0007]
[ 17.636887] pci 0000:03:00.0: reg 0x1c: [io 0x0000-0x0003]
[ 17.648009] pci 0000:03:00.0: reg 0x20: [io 0x0000-0x000f]
[ 17.659119] pci 0000:03:00.0: reg 0x24: initial BAR value 0x00000000 invalid
[ 17.673162] pci 0000:03:00.0: reg 0x24: [mem size 0x00000200]
[ 17.684777] pci 0000:03:00.0: 2.000 Gb/s available PCIe bandwidth,
limited by 2.5 GT/s PCIe x1 link at 0000:00:02.0 (capable of 4.000
Gb/s with 5.0 GT/s PCIe x1 link)
[ 17.737561] pci 0000:00:02.0: PCI bridge to [bus 03-ff]
[ 17.748022] pci 0000:00:02.0: bridge window [io 0x0000-0x0fff]
[ 17.760167] pci 0000:00:02.0: bridge window [mem 0x60000000-0x600fffff]
[ 17.773690] pci 0000:00:02.0: bridge window [mem
0x60000000-0x600fffff pref]
[ 17.788085] pci_bus 0000:03: busn_res: [bus 03-ff] end is updated to 03
[ 17.801341] pci 0000:00:00.0: BAR 0: no space for [mem size 0x80000000]
[ 17.814518] pci 0000:00:00.0: BAR 0: failed to assign [mem size 0x80000000]
[ 17.828392] pci 0000:00:01.0: BAR 0: no space for [mem size 0x80000000]
[ 17.841571] pci 0000:00:01.0: BAR 0: failed to assign [mem size 0x80000000]
[ 17.855443] pci 0000:00:02.0: BAR 0: no space for [mem size 0x80000000]
[ 17.868626] pci 0000:00:02.0: BAR 0: failed to assign [mem size 0x80000000]
[ 17.882502] pci 0000:00:00.0: BAR 8: assigned [mem 0x60000000-0x600fffff]
[ 17.896028] pci 0000:00:00.0: BAR 9: assigned [mem
0x60100000-0x601fffff pref]
[ 17.910419] pci 0000:00:01.0: BAR 8: assigned [mem 0x60200000-0x602fffff]
[ 17.923951] pci 0000:00:01.0: BAR 9: assigned [mem
0x60300000-0x603fffff pref]
[ 17.938353] pci 0000:00:02.0: BAR 8: assigned [mem 0x60400000-0x604fffff]
[ 17.951879] pci 0000:00:02.0: BAR 9: assigned [mem
0x60500000-0x605fffff pref]
[ 17.966273] pci 0000:00:00.0: BAR 1: assigned [mem 0x60600000-0x6060ffff]
[ 17.979809] pci 0000:00:01.0: BAR 1: assigned [mem 0x60610000-0x6061ffff]
[ 17.993341] pci 0000:00:02.0: BAR 1: assigned [mem 0x60620000-0x6062ffff]
[ 18.006877] pci 0000:00:00.0: BAR 7: assigned [io 0x1e160000-0x1e160fff]
[ 18.020408] pci 0000:00:01.0: BAR 7: assigned [io 0x1e161000-0x1e161fff]
[ 18.033932] pci 0000:00:02.0: BAR 7: assigned [io 0x1e162000-0x1e162fff]
[ 18.047472] pci 0000:01:00.0: BAR 5: assigned [mem 0x60000000-0x600001ff]
[ 18.061005] pci 0000:01:00.0: BAR 4: assigned [io 0x1e160000-0x1e16000f]
[ 18.074540] pci 0000:01:00.0: BAR 0: assigned [io 0x1e160010-0x1e160017]
[ 18.088070] pci 0000:01:00.0: BAR 2: assigned [io 0x1e160018-0x1e16001f]
[ 18.101606] pci 0000:01:00.0: BAR 1: assigned [io 0x1e160020-0x1e160023]
[ 18.115139] pci 0000:01:00.0: BAR 3: assigned [io 0x1e160024-0x1e160027]
[ 18.128676] pci 0000:00:00.0: PCI bridge to [bus 01]
[ 18.138577] pci 0000:00:00.0: bridge window [io 0x1e160000-0x1e160fff]
[ 18.152100] pci 0000:00:00.0: bridge window [mem 0x60000000-0x600fffff]
[ 18.165627] pci 0000:00:00.0: bridge window [mem
0x60100000-0x601fffff pref]
[ 18.180030] pci 0000:02:00.0: BAR 5: assigned [mem 0x60200000-0x602001ff]
[ 18.193566] pci 0000:02:00.0: BAR 4: assigned [io 0x1e161000-0x1e16100f]
[ 18.207110] pci 0000:02:00.0: BAR 0: assigned [io 0x1e161010-0x1e161017]
[ 18.220648] pci 0000:02:00.0: BAR 2: assigned [io 0x1e161018-0x1e16101f]
[ 18.234183] pci 0000:02:00.0: BAR 1: assigned [io 0x1e161020-0x1e161023]
[ 18.247723] pci 0000:02:00.0: BAR 3: assigned [io 0x1e161024-0x1e161027]
[ 18.261257] pci 0000:00:01.0: PCI bridge to [bus 02]
[ 18.271165] pci 0000:00:01.0: bridge window [io 0x1e161000-0x1e161fff]
[ 18.284695] pci 0000:00:01.0: bridge window [mem 0x60200000-0x602fffff]
[ 18.298225] pci 0000:00:01.0: bridge window [mem
0x60300000-0x603fffff pref]
[ 18.312630] pci 0000:03:00.0: BAR 5: assigned [mem 0x60400000-0x604001ff]
[ 18.326166] pci 0000:03:00.0: BAR 4: assigned [io 0x1e162000-0x1e16200f]
[ 18.339702] pci 0000:03:00.0: BAR 0: assigned [io 0x1e162010-0x1e162017]
[ 18.353237] pci 0000:03:00.0: BAR 2: assigned [io 0x1e162018-0x1e16201f]
[ 18.366775] pci 0000:03:00.0: BAR 1: assigned [io 0x1e162020-0x1e162023]
[ 18.380311] pci 0000:03:00.0: BAR 3: assigned [io 0x1e162024-0x1e162027]
[ 18.393841] pci 0000:00:02.0: PCI bridge to [bus 03]
[ 18.403740] pci 0000:00:02.0: bridge window [io 0x1e162000-0x1e162fff]
[ 18.417270] pci 0000:00:02.0: bridge window [mem 0x60400000-0x604fffff]
[ 18.430801] pci 0000:00:02.0: bridge window [mem
0x60500000-0x605fffff pref]
[ 18.445529] ahci 0000:01:00.0: version 3.0
[ 18.445559] pci 0000:00:00.0: enabling device (0000 -> 0003)
[ 18.456853] ahci 0000:01:00.0: enabling device (0000 -> 0003)
[ 18.468455] ahci 0000:01:00.0: SSS flag set, parallel bus scan disabled
[ 18.481700] ahci 0000:01:00.0: AHCI 0001.0200 32 slots 2 ports 6
Gbps 0x3 impl IDE mode
[ 18.497662] ahci 0000:01:00.0: flags: 64bit ncq sntf stag led clo
pmp pio slum part ccc sxs
[ 18.516777] scsi host0: ahci
[ 18.523629] scsi host1: ahci
[ 18.529829] ata1: SATA max UDMA/133 abar m512@0x60000000 port
0x60000100 irq 22
[ 18.544447] ata2: SATA max UDMA/133 abar m512@0x60000000 port
0x60000180 irq 22
[ 18.559465] pci 0000:00:01.0: enabling device (0000 -> 0003)
[ 18.570786] ahci 0000:02:00.0: enabling device (0000 -> 0003)
[ 18.582414] ahci 0000:02:00.0: SSS flag set, parallel bus scan disabled
[ 18.595665] ahci 0000:02:00.0: AHCI 0001.0200 32 slots 2 ports 6
Gbps 0x3 impl IDE mode
[ 18.611614] ahci 0000:02:00.0: flags: 64bit ncq sntf stag led clo
pmp pio slum part ccc sxs
[ 18.631053] scsi host2: ahci
[ 18.637983] scsi host3: ahci
[ 18.644138] ata3: SATA max UDMA/133 abar m512@0x60200000 port
0x60200100 irq 23
[ 18.658792] ata4: SATA max UDMA/133 abar m512@0x60200000 port
0x60200180 irq 23
[ 18.673827] pci 0000:00:02.0: enabling device (0000 -> 0003)
[ 18.685151] ahci 0000:03:00.0: enabling device (0000 -> 0003)
[ 18.696782] ahci 0000:03:00.0: SSS flag set, parallel bus scan disabled
[ 18.710025] ahci 0000:03:00.0: AHCI 0001.0200 32 slots 2 ports 6
Gbps 0x3 impl IDE mode
[ 18.725972] ahci 0000:03:00.0: flags: 64bit ncq sntf stag led clo
pmp pio slum part ccc sxs

And you are totally right, the setting is writing in the wrong place.
I changed the device tree and the way interrupts are mapped
to avoid using a custom 'map_irq' function [1]. Before that commit the
pci virtual bridge register was reordering the
buses enumeration depending on link status, so there I should also
properly rewrite the code in question.

I can rewrite the code to read and write config properly using the
slot moving the code into 'mt7621_pcie_enable_port' as follows:

static void mt7621_pcie_enable_port(struct mt7621_pcie_port *port)
{
struct mt7621_pcie *pcie = port->pcie;
u32 slot = port->slot;
u32 offset = MT7621_PCIE_OFFSET + (slot * MT7621_NEXT_PORT);
u32 val;

/* enable pcie interrupt */
val = pcie_read(pcie, RALINK_PCI_PCIMSK_ADDR);
val |= PCIE_PORT_INT_EN(slot);

/* map 2G DDR region */
pcie_write(pcie, PCIE_BAR_MAP_MAX | PCIE_BAR_ENABLE,
offset + RALINK_PCI_BAR0SETUP_ADDR);

/* configure class code and revision ID */
pcie_write(pcie, PCIE_CLASS_CODE | PCIE_REVISION_ID,
offset + RALINK_PCI_CLASS);

/* configure RC FTS number to 250 when it leaves L0s */
val = read_config(pcie, slot, PCIE_FTS_NUM);
val &= ~PCIE_FTS_NUM_MASK;
val |= PCIE_FTS_NUM_L0(0x50);
write_config(pcie, slot, PCIE_FTS_NUM, val);
}

static int mt7621_pcie_enable_ports(struct mt7621_pcie *pcie)
{
struct device *dev = pcie->dev;
struct mt7621_pcie_port *port;
int err;

/* Setup MEMWIN and IOWIN */
pcie_write(pcie, 0xffffffff, RALINK_PCI_MEMBASE);
pcie_write(pcie, pcie->io.start, RALINK_PCI_IOBASE);

list_for_each_entry(port, &pcie->ports, list) {
if (port->enabled) {
err = clk_prepare_enable(port->clk);
if (err) {
dev_err(dev, "enabling clk pcie%d\n",
port->slot);
return err;
}

mt7621_pcie_enable_port(port);
dev_info(dev, "PCIE%d enabled\n", port->slot);
}
}

return 0;
}

Or just delete the setting and the read and write config functions
since they are not being used in any other place. My two boards work
without this setting but I don't know about other boards.

What do you think?

Best regards,
Sergio Paracuellos

[0]: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git/tree/drivers/staging/mt7621-pci/pci-mt7621.c?h=v4.18#n663
[1]: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git/commit/drivers/staging/mt7621-pci?h=staging-testing&id=b99cc3a2b6b62cf994acac5cced03298d9908c9b

>
> > Device tree node: /sys/firmware/devicetree/base/pcie@1e140000/pcie@2,0
> > Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop-
> > ParErr- Stepping- SERR- FastB2B- DisINTx-
> > Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort-
> > <TAbort- <MAbort- >SERR- <PERR- INTx-
> > Latency: 0
> > Interrupt: pin A routed to IRQ 255
> > Region 1: Memory at 60200000 (32-bit, non-prefetchable) [size=64K]
> > Bus: primary=00, secondary=01, subordinate=01, sec-latency=0
> > I/O behind bridge: 00000000-00000fff [size=4K]
> > Memory behind bridge: 60000000-600fffff [size=1M]
> > Prefetchable memory behind bridge: 60100000-601fffff [size=1M]
> > Secondary status: 66MHz- FastB2B- ParErr- DEVSEL=fast >TAbort-
> > <TAbort- <MAbort- <SERR- <PERR-
> > BridgeCtl: Parity- SERR+ NoISA- VGA- VGA16- MAbort- >Reset- FastB2B-
> > PriDiscTmr- SecDiscTmr- DiscTmrStat- DiscTmrSERREn-
> > Capabilities: [40] Power Management version 3
> > Flags: PMEClk- DSI- D1+ D2- AuxCurrent=375mA
> > PME(D0+,D1+,D2-,D3hot+,D3cold-)
> > Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
> > Capabilities: [50] MSI: Enable- Count=1/1 Maskable- 64bit+
> > Address: 0000000000000000 Data: 0000
> > Capabilities: [70] Express (v2) Root Port (Slot-), MSI 00
> > DevCap: MaxPayload 128 bytes, PhantFunc 0
> > ExtTag- RBE+
> > DevCtl: CorrErr- NonFatalErr- FatalErr- UnsupReq-
> > RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop-
> > MaxPayload 128 bytes, MaxReadReq 128 bytes
> > DevSta: CorrErr+ NonFatalErr- FatalErr- UnsupReq-
> > AuxPwr- TransPend-
> > LnkCap: Port #0, Speed 2.5GT/s, Width x1, ASPM L0s L1,
> > Exit Latency L0s <512ns, L1 <64us
> > ClockPM- Surprise- LLActRep+ BwNot- ASPMOptComp-
> > LnkCtl: ASPM Disabled; RCB 128 bytes, Disabled- CommClk-
> > ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
> > LnkSta: Speed 2.5GT/s (ok), Width x1 (ok)
> > TrErr- Train- SlotClk+ DLActive+ BWMgmt- ABWMgmt-
> > RootCap: CRSVisible-
> > RootCtl: ErrCorrectable- ErrNon-Fatal- ErrFatal-
> > PMEIntEna- CRSVisible-
> > RootSta: PME ReqID 0000, PMEStatus- PMEPending-
> > DevCap2: Completion Timeout: Not Supported,
> > TimeoutDis+ NROPrPrP- LTR-
> > 10BitTagComp- 10BitTagReq- OBFF Not
> > Supported, ExtFmt- EETLPPrefix-
> > EmergencyPowerReduction Not Supported,
> > EmergencyPowerReductionInit-
> > FRS- LN System CLS Not Supported, TPHComp-
> > ExtTPHComp- ARIFwd-
> > AtomicOpsCap: Routing- 32bit- 64bit- 128bitCAS-
> > DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-
> > LTR- OBFF Disabled, ARIFwd-
> > AtomicOpsCtl: ReqEn- EgressBlck-
> > LnkCap2: Supported Link Speeds: 2.5GT/s, Crosslink-
> > Retimer- 2Retimers- DRS-
> > LnkCtl2: Target Link Speed: 2.5GT/s, EnterCompliance- SpeedDis-
> > Transmit Margin: Normal Operating Range,
> > EnterModifiedCompliance- ComplianceSOS-
> > Compliance De-emphasis: -6dB
> > LnkSta2: Current De-emphasis Level: -6dB,
> > EqualizationComplete- EqualizationPhase1-
> > EqualizationPhase2- EqualizationPhase3-
> > LinkEqualizationRequest-
> > Retimer- 2Retimers- CrosslinkRes: unsupported
> > Capabilities: [100 v1] Advanced Error Reporting
> > UESta: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt-
> > UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
> > UEMsk: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt-
> > UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
> > UESvrt: DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt-
> > UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
> > CESta: RxErr+ BadTLP- BadDLLP- Rollover- Timeout-
> > AdvNonFatalErr-
> > CEMsk: RxErr- BadTLP- BadDLLP- Rollover- Timeout-
> > AdvNonFatalErr+
> > AERCap: First Error Pointer: 00, ECRCGenCap+
> > ECRCGenEn- ECRCChkCap+ ECRCChkEn-
> > MultHdrRecCap- MultHdrRecEn- TLPPfxPres- HdrLogCap-
> > HeaderLog: 00000000 00000000 00000000 00000000
> > RootCmd: CERptEn- NFERptEn- FERptEn-
> > RootSta: CERcvd- MultCERcvd- UERcvd- MultUERcvd-
> > FirstFatal- NonFatalMsg- FatalMsg- IntMsg 0
> > ErrorSrc: ERR_COR: 0000 ERR_FATAL/NONFATAL: 0000
> > Capabilities: [140 v1] Virtual Channel
> > Caps: LPEVC=0 RefClk=100ns PATEntryBits=1
> > Arb: Fixed- WRR32- WRR64- WRR128-
> > Ctrl: ArbSelect=Fixed
> > Status: InProgress-
> > VC0: Caps: PATOffset=00 MaxTimeSlots=1 RejSnoopTrans-
> > Arb: Fixed- WRR32- WRR64- WRR128- TWRR128- WRR256-
> > Ctrl: Enable+ ID=0 ArbSelect=Fixed TC/VC=ff
> > Status: NegoPending- InProgress-
> > lspci: Unable to load libkmod resources: error -12
> >
> > 01:00.0 Network controller [0280]: MEDIATEK Corp. Device [14c3:7612]
> > Subsystem: MEDIATEK Corp. Device [14c3:7612]
> > Device tree node:
> > /sys/firmware/devicetree/base/pcie@1e140000/pcie@2,0/wifi@0,0
> > Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop-
> > ParErr- Stepping- SERR- FastB2B- DisINTx-
> > Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort-
> > <TAbort- <MAbort- >SERR- <PERR- INTx-
> > Latency: 0
> > Interrupt: pin A routed to IRQ 20
> > Region 0: Memory at 60000000 (64-bit, non-prefetchable) [size=1M]
> > Expansion ROM at 60100000 [virtual] [disabled] [size=64K]
> > Capabilities: [40] Power Management version 3
> > Flags: PMEClk- DSI- D1- D2- AuxCurrent=375mA
> > PME(D0+,D1-,D2-,D3hot+,D3cold+)
> > Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
> > Capabilities: [50] MSI: Enable- Count=1/1 Maskable- 64bit+
> > Address: 0000000000000000 Data: 0000
> > Capabilities: [70] Express (v2) Endpoint, MSI 00
> > DevCap: MaxPayload 128 bytes, PhantFunc 0, Latency L0s
> > unlimited, L1 unlimited
> > ExtTag- AttnBtn- AttnInd- PwrInd- RBE+
> > FLReset- SlotPowerLimit 0.000W
> > DevCtl: CorrErr- NonFatalErr- FatalErr- UnsupReq-
> > RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop-
> > MaxPayload 128 bytes, MaxReadReq 128 bytes
> > DevSta: CorrErr- NonFatalErr- FatalErr- UnsupReq-
> > AuxPwr+ TransPend-
> > LnkCap: Port #0, Speed 2.5GT/s, Width x1, ASPM L0s L1,
> > Exit Latency L0s <2us, L1 unlimited
> > ClockPM+ Surprise- LLActRep- BwNot- ASPMOptComp+
> > LnkCtl: ASPM Disabled; RCB 64 bytes, Disabled- CommClk-
> > ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
> > LnkSta: Speed 2.5GT/s (ok), Width x1 (ok)
> > TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
> > DevCap2: Completion Timeout: Range ABCD, TimeoutDis+
> > NROPrPrP- LTR-
> > 10BitTagComp- 10BitTagReq- OBFF Not
> > Supported, ExtFmt- EETLPPrefix-
> > EmergencyPowerReduction Not Supported,
> > EmergencyPowerReductionInit-
> > FRS- TPHComp- ExtTPHComp-
> > AtomicOpsCap: 32bit- 64bit- 128bitCAS-
> > DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-
> > LTR- OBFF Disabled,
> > AtomicOpsCtl: ReqEn-
> > LnkCap2: Supported Link Speeds: 2.5GT/s, Crosslink-
> > Retimer- 2Retimers- DRS-
> > LnkCtl2: Target Link Speed: 5GT/s, EnterCompliance- SpeedDis-
> > Transmit Margin: Normal Operating Range,
> > EnterModifiedCompliance- ComplianceSOS-
> > Compliance De-emphasis: -6dB
> > LnkSta2: Current De-emphasis Level: -3.5dB,
> > EqualizationComplete- EqualizationPhase1-
> > EqualizationPhase2- EqualizationPhase3-
> > LinkEqualizationRequest-
> > Retimer- 2Retimers- CrosslinkRes: unsupported
> > Capabilities: [100 v2] Advanced Error Reporting
> > UESta: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt-
> > UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
> > UEMsk: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt-
> > UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
> > UESvrt: DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt-
> > UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
> > CESta: RxErr- BadTLP- BadDLLP- Rollover- Timeout-
> > AdvNonFatalErr-
> > CEMsk: RxErr- BadTLP- BadDLLP- Rollover- Timeout-
> > AdvNonFatalErr+
> > AERCap: First Error Pointer: 00, ECRCGenCap+
> > ECRCGenEn- ECRCChkCap+ ECRCChkEn-
> > MultHdrRecCap- MultHdrRecEn- TLPPfxPres- HdrLogCap-
> > HeaderLog: 00000000 00000000 00000000 00000000
> > Capabilities: [148 v1] Device Serial Number 00-00-00-00-00-00-00-00
> > Capabilities: [158 v1] Latency Tolerance Reporting
> > Max snoop latency: 0ns
> > Max no snoop latency: 0ns
> > Capabilities: [160 v1] L1 PM Substates
> > L1SubCap: PCI-PM_L1.2+ PCI-PM_L1.1+ ASPM_L1.2+
> > ASPM_L1.1+ L1_PM_Substates+
> > PortCommonModeRestoreTime=50us PortTPowerOnTime=10us
> > L1SubCtl1: PCI-PM_L1.2- PCI-PM_L1.1- ASPM_L1.2- ASPM_L1.1-
> > T_CommonMode=0us LTR1.2_Threshold=0ns
> > L1SubCtl2: T_PwrOn=10us
> > Kernel driver in use: mt76x2e
> >
> > Best regards,
> > Sergio Paracuellos
> >
> > >
> > > > > > > > > + }
> > > > > > > > > +
> > > > > > > > > + return 0;
> > > > > > > > > +}