Em Mon, 22 Feb 2021 16:47:36 +0100 Johan Hovold <jo...@kernel.org> escreveu:
> On Mon, Feb 22, 2021 at 04:27:34PM +0100, Mauro Carvalho Chehab wrote: > > Hi Johan, > > > > Em Tue, 26 Jan 2021 17:26:36 +0100 > > Johan Hovold <jo...@kernel.org> escreveu: > > > > > On Tue, Jan 26, 2021 at 09:16:04PM +0530, Manivannan Sadhasivam wrote: > > > > On Thu, Jan 21, 2021 at 11:19:24AM +0100, Johan Hovold wrote: > > > > > On Sun, Nov 22, 2020 at 10:38:20PM +0530, Manivannan Sadhasivam > > > > > wrote: > > > > > > Add support for MaxLinear/Exar USB to Serial converters. This driver > > > > > > only supports XR21V141X series but it can be extended to other > > > > > > series > > > > > > from Exar as well in future. > > > I'm now facing an issue with this driver. I have here two different > > boards with those USB UART from MaxLinear/Exar. > > > > The first one is identical to Mani's one: > > USB_DEVICE(0x04e2, 0x1411) > > The second one is a different version of it: > > USB_DEVICE(0x04e2, 0x1424) > > > > By looking at the final driver merged at linux-next, it sounds that > > somewhere during the review of this series, it lost the priv struct, > > and the xr_probe function. It also lost support for all MaxLinear/Exar > > devices, except for just one model (04e2:1411). > > > > The original submission: > > > > > > https://lore.kernel.org/linux-usb/20180404070634.nhspvmxcjwfgjkcv@advantechmxl-desktop > > > > And the manufacturer's Linux driver on their website: > > > > https://www.maxlinear.com/support/design-tools/software-drivers > > > > Had support for other 12 different models of the MaxLinear/Exar USB > > UART. > > IIRC Manivannan only had access to one of these models and his original > submission (based on the patch you link to above) didn't include support > for the others. And keeping the type abstraction didn't make sense for > just one model. > > > Those are grouped into 5 different major types: > > > > + init_xr2280x_reg_map(); > > + init_xr21b142x_reg_map(); > > + init_xr21b1411_reg_map(); > > + init_xr21v141x_reg_map(); > > + > > + if ((xrusb->DeviceProduct & 0xfff0) == 0x1400) > > + memcpy(&(xrusb->reg_map), &xr2280x_reg_map, > > + sizeof(struct reg_addr_map)); > > + else if ((xrusb->DeviceProduct & 0xFFF0) == 0x1420) > > + memcpy(&(xrusb->reg_map), &xr21b142x_reg_map, > > + sizeof(struct reg_addr_map)); > > + else if (xrusb->DeviceProduct == 0x1411) > > + memcpy(&(xrusb->reg_map), &xr21b1411_reg_map, > > + sizeof(struct reg_addr_map)); > > + else if ((xrusb->DeviceProduct & 0xfff0) == 0x1410) > > + memcpy(&(xrusb->reg_map), &xr21v141x_reg_map, > > + sizeof(struct reg_addr_map)); > > + else > > + rv = -1; > > > > Note: Please don't be confused by "reg_map" name. This has nothing > > to do with Linux regmap API ;-) > > > > What happens is that different USB IDs have different values for > > each register. So, for instance, the UART enable register is set to > > either one of the following values, depending on the value of > > udev->descriptor.idProduct: > > > > xr21b140x_reg_map.uart_enable_addr = 0x00; > > xr21b1411_reg_map.uart_enable_addr = 0xc00; > > xr21v141x_reg_map.uart_enable_addr = 0x03; > > xr21b142x_reg_map.uart_enable_addr = 0x00; > > > > There are other values that depend on the probing time detection, > > based on other USB descriptors. Those set several fields at the > > priv data that would allow to properly map the registers. > > > > Also, there are 4 models that support multiple channels. On those, > > there are one pair of register get/set for each channel. > > > > - > > > > In summary, while supporting just 04e2:1411 there's no need for > > a private struct, in order to properly support the other models, > > some autodetection is needed. The best way of doing that is to > > re-add the .probe method and adding a priv struct. > > > > As I dunno why this was dropped in the first place, I'm wondering > > if it would be ok to re-introduce them. > > Sure. It was just not needed if we were only going to support one model. > > > To be clear: my main focus here is just to avoid needing to use > > Windows in order to use the serial console of the hardware with > > the 0x1424 variant ;-) > > > > I can't test the driver with the other hardware, but, IMHO, instead > > of adding a hack to support 0x1424, the better (but more painful) > > would be to re-add the auto-detection part and support for the > > other models. > > Sounds good to me. While testing the xr_serial (as currently merged), I opted to apply the patches on the top of vanilla Kernel 5.11 - as it sounds too risky to use linux-next so early on a new development cycle :-) There, I'm getting an OOPS: [ 30.261291] BUG: kernel NULL pointer dereference, address: 00000000000000a8 [ 30.261375] #PF: supervisor write access in kernel mode [ 30.261438] #PF: error_code(0x0002) - not-present page [ 30.261500] PGD 0 P4D 0 [ 30.261539] Oops: 0002 [#1] SMP PTI [ 30.261586] CPU: 2 PID: 686 Comm: kworker/2:3 Not tainted 5.11.0+ #14 [ 30.261666] Hardware name: /NUC5i7RYB, BIOS RYBDWi35.86A.0380.2019.0517.1530 05/17/2019 [ 30.261757] Workqueue: usb_hub_wq hub_event [ 30.261816] RIP: 0010:mutex_lock+0x1e/0x40 [ 30.261875] Code: c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 55 48 89 e5 41 54 49 89 fc e8 8d dd ff ff 31 c0 65 48 8b 14 25 c0 7b 01 00 <f0> 49 0f b1 14 24 75 04 41 5c 5d c3 4c 89 e7 e8 ae ff ff ff 41 5c [ 30.262076] RSP: 0018:ffffb937c0767b70 EFLAGS: 00010246 [ 30.262140] RAX: 0000000000000000 RBX: ffff95e71ef75430 RCX: 0000000000000027 [ 30.262223] RDX: ffff95e70597b000 RSI: 00000000ffffdfff RDI: 00000000000000a8 [ 30.262305] RBP: ffffb937c0767b78 R08: ffff95ea76d18ac0 R09: ffffb937c0767948 [ 30.262387] R10: 0000000000000001 R11: 0000000000000001 R12: 00000000000000a8 [ 30.262469] R13: 0000000000000000 R14: ffff95e71ef75400 R15: 0000000000000000 [ 30.262551] FS: 0000000000000000(0000) GS:ffff95ea76d00000(0000) knlGS:0000000000000000 [ 30.262645] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 30.262713] CR2: 00000000000000a8 CR3: 000000042be0a002 CR4: 00000000003706e0 [ 30.262796] Call Trace: [ 30.262832] usb_serial_disconnect+0x33/0x140 [ 30.262897] usb_unbind_interface+0x8c/0x260 [ 30.262957] device_release_driver_internal+0x103/0x1d0 [ 30.263026] device_release_driver+0x12/0x20 [ 30.263083] bus_remove_device+0xe1/0x150 [ 30.263140] device_del+0x192/0x3f0 [ 30.263188] ? usb_remove_ep_devs+0x1f/0x30 [ 30.263244] usb_disable_device+0x95/0x1c0 [ 30.263300] usb_disconnect+0xc0/0x270 [ 30.263350] hub_event+0xa2e/0x1620 After adding this hack: <snip> --- a/drivers/usb/serial/usb-serial.c +++ b/drivers/usb/serial/usb-serial.c @@ -1081,6 +1081,11 @@ static void usb_serial_disconnect(struct usb_interface *interface) struct usb_serial_port *port; struct tty_struct *tty; + if (!serial) { + dev_err(dev, "%s: Serial pointer is NULL!!!\n", __func__); + return; + } + usb_serial_console_disconnect(serial); mutex_lock(&serial->disc_mutex); </snip> It works fine: [ 283.005625] xr_serial 2-1:1.1: xr_serial converter detected [ 283.005868] usb 2-1: xr_serial converter now attached to ttyUSB0 [ 283.007284] printk: console [ttyUSB0] enabled [ 284.444419] usb 2-1: USB disconnect, device number 5 [ 284.444520] xr_serial 2-1:1.0: usb_serial_disconnect: Serial pointer is NULL!!! [ 284.444894] printk: console [ttyUSB0] disabled [ 284.445091] xr_serial ttyUSB0: xr_serial converter now disconnected from ttyUSB0 [ 284.445141] xr_disconnect [ 284.445156] xr_serial 2-1:1.1: device disconnected I'm not sure if the bug is at xr_serial or if it is inside usb-serial.c. Any ideas? Thanks, Mauro
