On Wed, Jan 29, 2014 at 10:56:42AM -0700, Jason Gunthorpe wrote: > On Wed, Jan 29, 2014 at 03:34:18PM +0100, Boris BREZILLON wrote: > > [..] > > > +static int sunxi_nand_chip_init(struct device *dev, struct sunxi_nfc *nfc, > [..] > > + ret = sunxi_nand_chip_init_timings(chip, np); > > + if (ret) > > + return ret; > [..] > > + ret = nand_scan_ident(mtd, nsels, NULL); > > This ordering looks a bit problematic, will onfi_get_async_timing_mode > ever return anything other than ONFI_TIMING_MODE_UNKNOWN if it is > called before nand_scan_ident ? What sets clk_rate to non-zero if there > is no DT property? > > For a flow that uses onfi_get_async_timing_mode rather than DT the > driver should set the interface to timing mode 0 (slowest) and then > call nand_scan_ident, and then reset the interface to the detected > timing mode. > Yes. And I believe this is a requirement from the ONFI 2.1 spec: """ 4.1.4.3. Source Synchronous to Asynchronous [..] The host shall transition to the asynchronous data interface. Then the host shall issue the Reset (FFh) command described in the previous paragraph using asynchronous timing mode 0, thus the host transitions to the asynchronous data interface prior to issuing the Reset (FFh). A device in any timing mode is required to recognize a Reset (FFh) command issued in asynchronous timing mode 0. [..] After CE# has been pulled high and then transitioned low again, the host should issue a Set Features to select the appropriate asynchronous timing mode. """ -- Ezequiel García, Free Electrons Embedded Linux, Kernel and Android Engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
