[PATCH v2 1/4] tty: serial: Add 8250 earlycon to support noinit option
From: eddie.huang@mediatek.com (Eddie Huang)
Date: 2015-02-02 05:33:22
Also in:
linux-devicetree, linux-serial
Hi Peter, On Sun, 2015-02-01 at 21:24 -0800, Greg Kroah-Hartman wrote:
On Mon, Feb 02, 2015 at 12:15:31AM -0500, Peter Hurley wrote:quoted
On 02/01/2015 11:28 PM, Greg Kroah-Hartman wrote:quoted
On Sun, Feb 01, 2015 at 10:45:12PM -0500, Peter Hurley wrote:quoted
On 02/01/2015 10:16 PM, Eddie Huang wrote:quoted
quoted
I'll respin proper patches on top of Greg's tty-testing branch with reverts for the noinit options. I noticed that one of the noinit patches actually has the linkage for the mtk earlycon, so I'll be sure to preserve that.I can just drop the patches in the tty-testing branch, that's what it is there for :) Just let me know the specific patches and I will do so, thanks.Well that pretty much means dropping the 3 patches that add earlycon to 8250_mtk and then applying my patch (needs fixed to apply cleanly, which I can do) and then applying a fixed-up replacement patch to add earlycon to 8250_mtk (which I can also supply). Is that the way you want to go?Sounds good to me, send your patch, and I'll fix it all up tomorrow. thanks, greg k-h
Actually, your patch is a little different from my original idea. Although my use case only care about divisor now, but other hardware setting is still hard-code, not from parameter. In init_port() function: serial8250_early_out(port, UART_LCR, 0x3); /* 8n1 */ serial8250_early_out(port, UART_IER, 0);/* no interrupt */ serial8250_early_out(port, UART_FCR, 0); /* no fifo */ serial8250_early_out(port, UART_MCR, 0x3); /* DTR + RTS */ This is why I propose a new option "noinit". After checking further, in my case, I found that your patch should be unnecessary because if skip baudrate, probe_baud() read DLL/DLM register and init_port() write the same DLL/DLM value back, no touch any high speed register, which means keep uart divisor setting as loader Since I don't take "console=uart,mmio32,<addr>,noinit" into consideration, it is good to drop my patches in the tty-testing branch. For my case, I can send another series without noinit, just 8250_mtk.c and its linkage modification in 8250_early.c Eddie