[PATCH 1/3] mxc: Add support for the imx51 3-stack board

[Sascha Hauer]

On Wed, Jun 02, 2010 at 10:27:03PM +0800, jason wang wrote:
> 
> 
> > Hi Jason,
> > 
> > On Tue, Jun 01, 2010 at 11:10:41PM +0800, Jason Wang wrote:
> >> 3-stack is a reference board from Freescale for their i.MX51 SoC.
> >> 
> >> Add board definition, Kconfig and Makefile to enable Freescale 3-stack
> >> board.
> > 
> > The debug board code looks the same like in mach-mx31_3ds.c. Does
> > anybody know how similar the different debug boards for the 3ds boards
> > are? ATM we only have the mx31_3ds with debug board support in the
> > kernel. This could be the moment to go for a arch/arm/plat-mxc/3ds-debugboard.c
> > 
> Besides mx31_3ds and mx51_3ds, the mx31_ads and mx27_ads also have the similar CPLD expanding device.
> They have similar functions but different CPLD image version. That is to say, except base_addr and parent_irq_pin,
> the CPLD implemented device controller(like uart and interrupt controller) will be a little bit different.
> I think the software for this part could be moved to a common file like plat-mxc/mxc-debugboard.c
> 
> Because this is a big action, it will affect some exsiting platforms. How about leave this work to next
> action?
> 
> Thanks,
> Jason.
> > Several other comments inline.
> > 
> Except following 1 comment, all others will be addressed in V2.
> 
> <snip>
> >> 
> >> Boot tested on a i.MX51 3-stack Rev2.0 board
> >> + __raw_writew(0xFFFF, brd_io + INTR_RESET_REG);
> >> + __raw_writew(0, brd_io + INTR_RESET_REG);
> >> + __raw_writew(0x1F, brd_io + INTR_MASK_REG);
> >> + for (i = MXC_BOARD_IRQ_START;
> >> +      i < (MXC_BOARD_IRQ_START + MXC_BOARD_IRQS); i++) {
> > 
> > MXC_BOARD_IRQS is the maximum number of interrupts available for the
> > board. What you need here instead is the number of interrupts the expio
> > actually has.
> > 
> It seems MXC_BOARD_IRQS is the number of CPLD expanding irq(or debugboard expanding irq).

Not exactly. See mach/irqs.h:

/*
 * The next 16 interrupts are for board specific purposes.  Since
 * the kernel can only run on one machine at a time, we can re-use
 * these.  If you need more, increase MXC_BOARD_IRQS, but keep it
 * within sensible limits.
 */
#define MXC_BOARD_IRQ_START     (MXC_INTERNAL_IRQS + MXC_GPIO_IRQS)

#ifdef CONFIG_MACH_MX31ADS_WM1133_EV1
#define MXC_BOARD_IRQS  80
#else
#define MXC_BOARD_IRQS  16
#endif


Remember that we can compile the kernel for more than one board at a
time. So if MACH_MX31ADS_WM1133_EV1 is compiled in we will have 60 board
irqs. Ok, you will hardly compile a kernel for mx31ads and mx51, but
there could well come a mx51 board with more irqs in which case your
expio handler goes nuts.

Sascha


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