Messages in this thread | | | From | "Matthieu CASTET" <> | Subject | Re: [PATCH 1/4] Blackfin: arch patch for 2.6.18 | Date | Sat, 23 Sep 2006 11:28:05 +0000 (UTC) |
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Hi,
On Sat, 23 Sep 2006 02:50:02 -0400, Mike Frysinger wrote:
>> It would be nice if you could use a generic way to pass this partition data >> to the kernel from the mtd medium, instead of hardcoding it here. > > i often wish for such things myself :) > > unfortunately, the boot loader we utilize (u-boot) isnt exactly > friendly to the idea of managing flash partitions like redboot, and > what we have here is the current standard method for defining flash > partitions with mtd >
humm you could use cmdlinepart [1] and pass the partition as a kernel string with uboot.
That's what we are doing and it works perfectly.
>> > +/* Clock and System Control (0xFFC0 0400-0xFFC0 07FF) */ >> > +#define bfin_read_PLL_CTL() bfin_read16(PLL_CTL) >> > +#define bfin_write_PLL_CTL(val) bfin_write16(PLL_CTL,val) >> > +#define bfin_read_PLL_STAT() bfin_read16(PLL_STAT) >> (and 700 more of these) >> >> What's the point, are you getting paid by lines of code? Just use >> the registers directly! > > in our last submission we were doing exactly that ... and we were told > to switch to a function style method of reading/writing memory mapped > registers hum, IRRC in your last submission you used volatile to read/write register. Some people told you that volatile are evil and you should use a function to read them.
But there no need to these defines. Just use bfin_read16(register_name) in your code.
For an example look at arch/mips/au1000/common/usbdev.c for a driver using memory mapped register. Also you could use standard function like readl/writel if there no special constraint (on the example a special function is needed because readl/writel do some byteswapping on that platform (need for external device), that is not need for memory mapped register).
Hope it will help you to improve your code.
Matthieu
[1] see drivers/mtd/cmdlinepart.c for more information. For example 1 NOR Flash with 2 partitions, 1 NAND with one edb7312-nor:256k(ARMboot)ro,-(root);edb7312-nand:-(home)
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