On Fri, May 28, 2010 at 12:03 PM, Ghorai, Sukumar <s-ghorai@xxxxxx> wrote: > >> -----Original Message----- >> From: linux-omap-owner@xxxxxxxxxxxxxxx [mailto:linux-omap- >> owner@xxxxxxxxxxxxxxx] On Behalf Of Vimal Singh >> Sent: Thursday, May 27, 2010 11:56 PM >> To: Ghorai, Sukumar >> Cc: linux-omap@xxxxxxxxxxxxxxx >> Subject: Re: [PATCH v4 1/3] omap3 gpmc: functionality enhancement >> >> On Thu, May 27, 2010 at 6:54 PM, Sukumar Ghorai <s-ghorai@xxxxxx> wrote: >> [...] >> > -static unsigned gpmc_cs_map; >> > +static unsigned int gpmc_cs_map; /* flag for cs which are >> initialized */ >> >> Tab should be after 'int', not before. >> >> [...] >> > @@ -456,13 +565,22 @@ EXPORT_SYMBOL(gpmc_prefetch_enable); >> > /** >> > * gpmc_prefetch_reset - disables and stops the prefetch engine >> > */ >> > -void gpmc_prefetch_reset(void) >> > +int gpmc_prefetch_reset(int cs) >> > { >> > + u32 config1; >> > + >> > + /* check if the same module/cs is trying to reset */ >> > + config1 = gpmc_read_reg(GPMC_PREFETCH_CONFIG1); >> > + if (((config1 >> CS_NUM_SHIFT) & 0x7) != cs) >> > + return -EINVAL; >> > + >> >> You really do not need this. >> Prefetch has just one instance at a time and 'reset' will be call only >> when driver has got access to prefetch (for either read or write >> access), from the driver. > [Ghorai] Agree. And.. NAND may not be good example. But if tomorrow i/o operation need to cancel for some other type of device and for big size of IO on progress. So is not this API required that case? > First of all, this prefetch engine is dedicated for only NAND. Then, if user wants to 'cancel', say a big write operation; since there is no 'cancel' command provided by chip (nand), FS has to handle it. And, I guess, best way will be to complete current chunck of request (in this case writing of current page or sub-page) and then cancel any further pending transfer. And in that case again, prefetch 'reset' will get called for completion of current page/sub-page operation. -- Regards, Vimal Singh -- 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
