On Fri, Oct 3, 2014 at 8:29 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote: > On Thursday 02 October 2014 12:05:27 Andy Lutomirski wrote: >> On 10/02/2014 06:44 AM, Kalle Valo wrote: >> > Hi Mark, >> > >> > Mark Rutland <mark.rutland-5wv7dgnIgG8@xxxxxxxxxxxxxxxx> writes: >> > >> >>> ath10k is a wireless driver for Qualcomm Atheros 802.11ac hardware and >> >>> located in drivers/net/wireless/ath/ath10k/. Currently it only supports >> >>> PCI devices. >> >>> >> >>> Some of the devices store the calibration data to the host flash and the >> >>> bootloader reads the data from the flash. And now we need a method to >> >>> deliver the calibration data from bootloader to ath10k. >> >> >> >> What does this calibration data consist of? >> > >> > From ath10k point of view it's just a binary blob which we push to the >> > firmware before we start it. ath10k does not parse it in any way. >> > >> >> What happens if you don't have the calibration data? Is it a critical >> >> requirement for the use of the device, or does its absence simply result >> >> in degraded performance? >> > >> > From my point of view the device should not be used if it doesn't >> > contain the correct calibration data. I guess it could work somehow but >> > there's no guarantee about the perfomance. >> > >> >> What do you do on non-DT systems? Where does the information come from >> >> in that case? >> > >> > Currently ath10k only supports having the calibration data in the OTP >> > area inside the QCA98XX chip. But some manufacturers want to store it on >> > the host file, I assume because of the flexibility it provides. And >> > that's why we have the need for Device Tree support. >> >> To give an actual concrete example that might be what Kalle is talking >> about: >> >> I have a TP-Link Archer C7, which has a mips cpu and an ath10k minipcie >> device. For whatever reason (I honestly have no clue whatsoever why the >> hardware works this way), the calibration data is on a host flash >> partition, not on the minipcie device's ROM or flash or whatever it is. > > Just to clarify: is this data specific to the design of the device and > identical for all parts in a manufacture run, or does each individual > board have to be calibrated separately? Each board has separate data. (Even the MAC address is in this blob on my device.) --Andy -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
