Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx> writes: > Kevin, > > On Thu, 04 Oct 2012 10:18:04 -0700, Kevin Hilman wrote: > >> Can you dump the UART mux registers on a working kernel and compare >> them to the broken one? (Table 7-4 in the 34xx public TRM[1] will >> list all the mux registers.) Maybe the bootloader code for that >> board will shed some light as well since it will be setting the >> muxing too. >> >> If the console uart is ttyO2 (UART3 in TI docs), then the interesting >> registers will be any of the padconf registers in that table that >> contain 'uart3'. e.g. for UART3 RX: >> >> CONTROL_PADCONF_DSS_DATA4 (mode 2) >> CONTROL_PADCONF_UART3_RTS_SD (mode 0) >> CONTROL_PADCONF_HSUSB0_DATA1 (mode 2) >> >> omap_mux has some useful debugfs output under <debugfs>/omap_mux. For >> example: >> >> # cd /sys/kernel/debug/omap_mux >> # cat dss_data4 >> # cat uart3_rx_irrx >> # cat hsusb0_data1 >> >> would provide a very useful comparison between a working kernel and a >> non-working one. > > It seems they are exactly the same, unless my eyes missed something, of course. The example I gave was only for the UART3 RX, you should dump the UART3 TX pins as. Using the omap_mux debugfs, you can see all of the potential pins where uart3_tx can be routed: # cd /sys/kernel/debug/omap_mux # grep -H uart3_tx * |grep signal dss_data5:signals: dss_data5 | NA | uart3_tx_irtx | NA | gpio_75 | NA | NA | safe_mode hsusb0_data0:signals: hsusb0_data0 | NA | uart3_tx_irtx | NA | gpio_125 | NA | NA | safe_mode uart3_tx_irtx:signals: uart3_tx_irtx | NA | NA | NA | gpio_166 | NA | NA | safe_mode So a 'cat' on dss_data, hsusb0_data0 and uart3_tx_irtx on a working an non-working kernel should point us in the right direction (assuming of course, that it's acutally a muxing problem that we're after.) [...] > Regarding the bootloader, I am not 100% sure what are the relevant > bits, but the UART3 related muxing for this board, done in U-Boot seems > to be: > > MUX_VAL(CP(UART3_TX_IRTX), (IDIS | PTD | DIS | M0)) /* UART3_TX */\ > MUX_VAL(CP(UART3_RX_IRRX), (IEN | PTD | DIS | M0)) /* UART3_RX */\ > > Does this helps? > Yes, that tells me where UART3 is expected to be mux'd on the board. So you can ignore the dss_data* and husb_data* files above and focus on uart3* So to summarize, in /sys/kernel/debug/omap_mux, just do a 'cat uart3*' on a working and non-working board and see if there are any differences. Kevin -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
