Messages in this thread | | | Date | Mon, 11 Jan 2016 16:07:23 +0100 | From | Sebastian Frias <> | Subject | Re: [RFC PATCH] always probe UART HW when options are not specified |
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On 12/22/2015 06:56 PM, Sebastian Frias wrote: > On 12/21/2015 05:50 PM, Sebastian Frias wrote: >>> You need to use the format documented in >>> Documentation/kernel-parameters.text: >>> >>> console= [KNL] Output console device and options. >>> >>> uart[8250],io,<addr>[,options] >>> uart[8250],mmio,<addr>[,options] >>> uart[8250],mmio16,<addr>[,options] >>> uart[8250],mmio32,<addr>[,options] >>> uart[8250],0x<addr>[,options] >>> Start an early, polled-mode console on the 8250/16550 >>> UART at the specified I/O port or MMIO address, >>> switching to the matching ttyS device later. >>> MMIO inter-register address stride is either 8-bit >>> (mmio), 16-bit (mmio16), or 32-bit (mmio32). >>> If none of [io|mmio|mmio16|mmio32], <addr> is assumed >>> to be equivalent to 'mmio'. 'options' are specified in >>> the same format described for ttyS above; if unspecified, >>> the h/w is not re-initialized. >>> >>> The iotype and the uart address are not options. >> >> Do you mean they are mandatory? >> How do they relate to the keys present on the DT? Because the device is >> already described in the DT: >> >> uart: serial@10700 { >> compatible = "ralink,rt2880-uart"; >> reg = <0x10700 0x30>; >> interrupts = <1 IRQ_TYPE_LEVEL_HIGH>; >> clock-frequency = <7372800>; >> reg-shift = <2>; >> }; >> >> Are we supposed to duplicate such information (ie: addr) in the >> commandline as well? >> > > By the way, I tried using the following command line > 'console=uart,mmio32,0x10700,115200n8r mem=256M earlyprintk debug > ignore_loglevel' but I think I'm still missing something regarding this, > because it does not work, here's a log of Linux 4.1.13+: > > > 1: [arch/arm/kernel/setup.c:932] setup_arch(): r1 = 0xf34, r2 = > 0x803b3b50, cmdline '' > 1: [arch/arm/kernel/devtree.c:195] arch_get_next_mach(): infoBegin > 0xc024faac, mdesc 0xc024faac > 1: [arch/arm/kernel/devtree.c:195] arch_get_next_mach(): infoBegin > 0xc024faac, mdesc 0xc024fb14 > 1: [drivers/of/fdt.c:106] of_fdt_is_compatible(): sigma,tango4 vs > sigma,vantage-1172 > 1: [arch/arm/kernel/devtree.c:195] arch_get_next_mach(): infoBegin > 0xc024faac, mdesc 0xc024fb7c > 1: [drivers/of/fdt.c:749] of_flat_dt_match_machine(): Machine model: > Sigma Designs SMP8758 Vantage-1172 Rev E1 > 1: [arch/arm/kernel/devtree.c:256] setup_machine_fdt(): about to call > early_init_dt_scan_nodes > 1: [drivers/of/fdt.c:1057] early_init_dt_scan_nodes(): bootcmdline '' > 1: [drivers/of/fdt.c:1062] early_init_dt_scan_nodes(): bootcmdline after > of_scan_flat_dt 'console=uart,mmio32,0x10700,115200n8r mem=256M > earlyprintk debug ignore_loglevel' > 1: [arch/arm/kernel/setup.c:946] setup_arch(): using DT at r2 > 1: [arch/arm/kernel/setup.c:949] setup_arch(): machine name Sigma Tango DT > 1: [arch/arm/kernel/setup.c:967] setup_arch(): before parse_early_param > 1: [init/main.c:468] parse_early_param(): bootcmdline > 'console=uart,mmio32,0x10700,115200n8r mem=256M earlyprintk debug > ignore_loglevel' > 1: [init/main.c:473] parse_early_param(): mark > 1: [init/main.c:428] do_early_param(): enter with: 'console' > 'uart,mmio32,0x10700,115200n8r' > 1: [init/main.c:446] do_early_param(): 'earlycon', setup_func 0xc024b868 > 1: [drivers/tty/serial/earlycon.c:214] param_setup_earlycon(): > 'uart,mmio32,0x10700,115200n8r' > 1: [drivers/tty/serial/earlycon.c:181] setup_earlycon(): > 'uart,mmio32,0x10700,115200n8r' > 1: [drivers/tty/serial/earlycon.c:132] register_earlycon(): > 'mmio32,0x10700,115200n8r' 'uart' > 1: [drivers/tty/serial/earlycon.c:86] parse_options(): > 'mmio32,0x10700,115200n8r' > 1: [drivers/tty/serial/earlycon.c:91] parse_options(): addr 0x00010700, > options '115200n8r' > 1: [drivers/tty/serial/earlycon.c:117] parse_options(): Early serial > console at MMIO32 0x10700 (options '115200n8r') > 1: [drivers/tty/serial/earlycon.c:138] register_earlycon(): '(null)' > 1: [drivers/tty/serial/earlycon.c:62] earlycon_map(): paddr 0x00010700 > size 64 > > As you can see, now that the options are more complete, the match for > "earlycon" succeeds, but it does not work, the last log is in > earlycon_map() function. > When using just "console=uart", the "earlycon" match will fail but a > match for "earlyprink" will succeed. That one will hook printch() from > the arch-dependent code to a somewhat simpler 'earlycon' > (arch/arm/kernel/early_printk.c). > > I think the code is the same on mainline. > > Also, regarding my previous question about using a HW described in DT > for earlycon, I noticed there's a of_setup_earlycon() in > drivers/tty/serial/earlycon.c but that is hooked to > drivers/of/fdt.c:setup_of_earlycon() which is not called. I do have > CONFIG_SERIAL_EARLYCON=y. > > I also have a similar issue (ie: get blocked right after the call to > earlycon_map function, log is obviously different from above) if attempt > to use of_setup_earlycon. > My DT has roughly: > > aliases { > serial0 = &uart; > }; > > chosen { > bootargs = "earlycon console mem=256M earlyprintk debug > ignore_loglevel"; > stdout-path = "serial0:115200n8"; > }; > > uart: serial@10700 { > compatible = "ralink,rt2880-uart"; > reg = <0x10700 0x30>; > interrupts = <1 IRQ_TYPE_LEVEL_HIGH>; > clock-frequency = <7372800>; > reg-shift = <2>; > }; > > > and then I hack drivers/tty/serial/8250/8250_early.c by adding: > > OF_EARLYCON_DECLARE(rt2880, "ralink,rt2880-uart", > early_serial8250_setup); > > at the end of the file, trying to mimic commit > d05f15707bb7659d2b863fafa1a918f286d74a63 > > I'm still trying to figure out the right bootargs, so that's why both > "earlycon" and "console" are there. Suggestions welcome. >
Does anybody has comments or suggestions regarding this thread and the issue above?
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