On Mon, Nov 30, 2009 at 10:09:58PM +0100, ext Tony Lindgren wrote: > * Peter Barada <peterb@xxxxxxxxxxx> [091130 12:30]: > > On Mon, 2009-11-30 at 11:40 -0800, Tony Lindgren wrote: > > > * Grant Likely <grant.likely@xxxxxxxxxxxx> [091130 09:01]: > > > > On Mon, Nov 30, 2009 at 9:36 AM, Peter Barada <peterb@xxxxxxxxxxx> wrote: > > > > > On Mon, 2009-11-30 at 10:46 +0200, Mika Westerberg wrote: > > > > >> Hi Tony, > > > > >> > > > > >> Current omap serial driver takes control of all 3 (4 on OMAP3640) > > > > >> UARTS. However, we have such a setup where UART2 for example is used > > > > >> by bluetooth driver. It uses the UART as non-standard way (there are > > > > >> some Nokia extensions to H4 protocol) so we cannot use the standard > > > > >> driver for driving the UART but have written special one for that > > > > >> purpose. > > > > >> > > > > >> Question is: Is there any, upstreamable, way of preventing omap serial > > > > >> driver to do this? Currently this is done with custom #ifdef hackery to > > > > >> mach-omap2/serial.c. Alternative solution that comes into mind is to > > > > >> specify UART configuration in board files and let serial driver to use > > > > >> that instead of hard-coded one. Or do you have some nice alternatives? > > > > > > > > > > Previously (back around 2.6.28-rc8) in the board file, the > > > > > omap_uart_config struct controlled which serial ports were enabled on > > > > > startup. It was used in omap_serial_init, and it looks like that code > > > > > went away with the following commit: > > > > > http://git.kernel.org/?p=linux/kernel/git/tmlind/linux-omap-2.6.git;a=blobdiff;f=arch/arm/mach-omap2/serial.c;h=2e17b57f5b23bb6703a2d621103585af1d8d729b;hp=555e735524381cbf8ef9f20d778ad81f9438e24e;hb=4355c41a635943d30e9396b95185314343dcb551;hpb=7e9ccf7776bb68b5367eb0bb35e519df62bea35c > > > > > > > > > > I'm kinda in the same boat as I want to use some of the unused serial > > > > > port pins for GPIO, but they are setup as serial ports.... > > > > > > Sounds like we need something back to specify the ports to use > > > from board-*.c files. Kevin, got any comments? > > > > > > > Not in mainlined yet, but I'm working on porting flattened device tree > > > > support to OMAP to solve exactly this sort of problem. Basically, > > > > instead of hard coding or #ifdeffing things, a data blob gets handed > > > > to the kernel at boot time telling it exactly what hardware is present > > > > in a consistent, parsable format. Device drivers then get probed > > > > based on data in the device tree. Here's some info on the approach: > > > > > > > > http://www.elinux.org/Device_Trees > > > > > > > > I expect to have my prototype ready for review mid-January, and most > > > > of the common code should be either merged or queued up in linux-next > > > > by that time. > > > > > > While device tree is a nice solution to some of the problems, it still > > > leaves all the issues we already have with buggy and and outdated > > > bootloaders. So we still need to properly initialize the devices in > > > the kernel. > > > > > > Just for reference, most of the omap bootloader bugs seem to be > > > related to not muxing the pins right or using wrong timings for GPMC. > > > > > > And then things that mostly change during the board development are > > > the GPIO pins, but those can be easily rewritten in the board-*.c > > > files based on the omap_rev. > > > > > > But at least the device tree is a standard model, while the earlier > > > omap tag approach was non-standard. > > > > > > Peter, maybe you've already thought through all this.. But would it be > > > possible to do lightweight device tree that we just use to populate > > > the platform data? > > > > One possibility is to pass to omap_serial_init() the omap_uart_config > > struct pointer to specify which parts are enabled. If a NULL is passed > > in, then enable all the ports available. Since omap_serial_early_init() > > was already called, the muxing would have to be cleaned up, but since > > the kernel should mux all the pins it uses, that shouldn't be a problem. > > omap_serial_init would now look something like(warning, coding on the > > fly - don't know if it will work as is): > > > > void __init omap_serial_init(struct omap_uart_config *confptr) > > { > > int i; > > > > for (i = 0; i < ARRAY_SIZE(omap_uart); i++) { > > struct omap_uart_state *uart = &omap_uart[i]; > > struct platform_device *pdev = &uart->pdev; > > struct device *dev = &pdev->dev; > > > > /* Only enable > > if (!confptr || confptr->port_enabled & (1<<i)) { > > omap_uart_reset(uart); > > omap_uart_idle_init(uart); > > > > if (WARN_ON(platform_device_register(pdev))) > > continue; > > if ((cpu_is_omap34xx() && uart->padconf) || > > (uart->wk_en && uart->wk_mask)) { > > device_init_wakeup(dev, true); > > DEV_CREATE_FILE(dev, &dev_attr_sleep_timeout); > > } > > } > > } > > } > > Yeah, I guess something like that would be good. We may want to > specify the optional other pins there too, typically it's just > RX and TX pins. > > It could also be directly struct plat_serial8250_port array we > pass? Or does that make things more complicated to use the upcoming > omap serial driver? How about something like in the patch attached? Then for example we would do in board-rx51.c: ... omap_serial_init_port(2); (we only use UART3 as serial port). I quickly tested this with RX-51 and seems to work. Thanks, MW --- From: Mika Westerberg <ext-mika.1.westerberg@xxxxxxxxx> Date: Tue, 1 Dec 2009 12:54:21 +0200 Subject: [PATCH] OMAP3: serial - allow platforms specify which UARTs to initialize This patch adds new function: omap_serial_init_port(port) that can be used to initialize only selected UARTs as serial ports. Platforms can then in their board files call this function instead of omap_serial_init() if they don't want to use all UARTs as serial ports. Signed-off-by: Mika Westerberg <ext-mika.1.westerberg@xxxxxxxxx> --- arch/arm/mach-omap2/serial.c | 59 +++++++++++++++++++++++------- arch/arm/plat-omap/include/plat/serial.h | 1 + 2 files changed, 46 insertions(+), 14 deletions(-) diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c index 2e17b57..fe46560 100644 --- a/arch/arm/mach-omap2/serial.c +++ b/arch/arm/mach-omap2/serial.c @@ -631,24 +631,55 @@ void __init omap_serial_early_init(void) } } +/** + * omap_serial_init_port() - initialize single serial port + * @port: serial port number (0-3) + * + * This function initialies serial driver for given @port only. + * Platforms can call this function instead of omap_serial_init() + * if they don't plan to use all available UARTs as serial ports. + * + * Don't mix calls to omap_serial_init_port() and omap_serial_init(), + * use only one of the two. + */ +void __init omap_serial_init_port(int port) +{ + struct omap_uart_state *uart; + struct platform_device *pdev; + struct device *dev; + + BUG_ON(port < 0); + BUG_ON(port >= ARRAY_SIZE(omap_uart)); + + uart = &omap_uart[port]; + pdev = &uart->pdev; + dev = &pdev->dev; + + omap_uart_reset(uart); + omap_uart_idle_init(uart); + + if (WARN_ON(platform_device_register(pdev))) + return; + + if ((cpu_is_omap34xx() && uart->padconf) || + (uart->wk_en && uart->wk_mask)) { + device_init_wakeup(dev, true); + DEV_CREATE_FILE(dev, &dev_attr_sleep_timeout); + } +} + +/** + * omap_serial_init() - intialize all supported serial ports + * + * Initializes all available UARTs as serial ports. Platforms + * can call this function when they want to have default behaviour + * for serial ports (e.g initialize them all as serial ports). + */ void __init omap_serial_init(void) { int i; for (i = 0; i < ARRAY_SIZE(omap_uart); i++) { - struct omap_uart_state *uart = &omap_uart[i]; - struct platform_device *pdev = &uart->pdev; - struct device *dev = &pdev->dev; - - omap_uart_reset(uart); - omap_uart_idle_init(uart); - - if (WARN_ON(platform_device_register(pdev))) - continue; - if ((cpu_is_omap34xx() && uart->padconf) || - (uart->wk_en && uart->wk_mask)) { - device_init_wakeup(dev, true); - DEV_CREATE_FILE(dev, &dev_attr_sleep_timeout); - } + omap_serial_init_port(i); } } diff --git a/arch/arm/plat-omap/include/plat/serial.h b/arch/arm/plat-omap/include/plat/serial.h index 9951345..f5a4a92 100644 --- a/arch/arm/plat-omap/include/plat/serial.h +++ b/arch/arm/plat-omap/include/plat/serial.h @@ -53,6 +53,7 @@ #ifndef __ASSEMBLER__ extern void __init omap_serial_early_init(void); extern void omap_serial_init(void); +extern void omap_serial_init_port(int port); extern int omap_uart_can_sleep(void); extern void omap_uart_check_wakeup(void); extern void omap_uart_prepare_suspend(void); -- 1.5.6.5 -- 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
