On 03/06/2012 05:23 AM, Stefano Babic wrote:
On 05/03/2012 17:34, Eric Nelson wrote:
Hi Eric,
If we're going to use globals to point at register banks, they should be constant and visible.
ok, but why are we going to use global pointers ? We have global constants (in imx-regs.h) and each part of code sets its local copy without using global pointers, that require also some rules and naming conventions to avoid conflicts.
I'm just trying to follow convention here. My preference would be to make these constants visible to the compiler in some way.
arch/arm/cpu/armv7/mx6/clock.c | 2 +- arch/arm/include/asm/arch-mx6/imx-regs.h | 2 ++ 2 files changed, 3 insertions(+), 1 deletions(-)
diff --git a/arch/arm/cpu/armv7/mx6/clock.c b/arch/arm/cpu/armv7/mx6/clock.c index ef98563..eb1f09b 100644 --- a/arch/arm/cpu/armv7/mx6/clock.c +++ b/arch/arm/cpu/armv7/mx6/clock.c @@ -34,7 +34,7 @@ enum pll_clocks { PLL_ENET, /* ENET PLL */ };
-struct imx_ccm_reg *imx_ccm = (struct imx_ccm_reg *)CCM_BASE_ADDR; +struct imx_ccm_reg *const imx_ccm = (struct imx_ccm_reg *)CCM_BASE_ADDR;
As far as I see, this is used only in clock.c - and it must be static.
I ran into this when trying to fix setup_sata() in mx6qsabrelite.c as shown in this patch.
The same sort of question (how to define the register sets) will occur for other register sets.
For the iomux, I used a #define, but that seems wrong too (not least because it isn't UPPERCASE).
#define iomuxc ((struct iomuxc_base_regs *)IOMUXC_BASE_ADDR)
The other way around this is to hide all register accesses behind the drivers. IOW, add routines for each of the accesses and hide the details in clock.c
void mx6_enable_sata_clock(); ...
void mx6_enable_enet_pll();
but there will almost certainly be board-specific tweaks and I'm not sure the extra level of abstraction helps.
Let me know your thoughts about how to structure this stuff.
Regards,
Eric