[LINUX, v8, 2/2] mtd: rawnand: pl353: Add basic driver for arm pl353 smc nand interface

[Naga Sureshkumar Relli]

Hi Miquel & Helmut,

Thanks for updating the latest changes.

> -----Original Message-----
> From: Miquel Raynal [mailto:miquel.raynal at bootlin.com]
> Sent: Thursday, May 3, 2018 7:56 PM
> To: Helmut Grohne <h.grohne at intenta.de>
> Cc: Naga Sureshkumar Relli <nagasure at xilinx.com>; linux-mtd at lists.infradead.org; Boris
> Brezillon <Boris.Brezillon at bootlin.com>
> Subject: Re: [LINUX, v8, 2/2] mtd: rawnand: pl353: Add basic driver for arm pl353 smc nand
> interface
> 
> Hi Naga,
> 
> On Thu, 3 May 2018 14:56:01 +0200, Helmut Grohne <h.grohne at intenta.de>
> wrote:
> 
> > On Wed, Mar 14, 2018 at 04:18:25PM +0530, Naga Sureshkumar Relli wrote:
> > > +	xnand->row_addr_cycles = nand_chip->onfi_params.addr_cycles & 0xF;
> > > +	xnand->col_addr_cycles =
> > > +				(nand_chip->onfi_params.addr_cycles >> 4) & 0xF;
> >
> > Meanwhile onfi_params have been removed from the mainline and this
> > patch no longer builds against v4.17-rc3. Can you resend a version
> > that builds against with more recent kernels?
> 
> Actually I'm not sure you need addr_cycles from the ONFI param page. What about non-
> ONFI chips? Anyway you won't find this entry anymore as the param page is now freed after
> probe.
> 
> I don't get why you need this though?
> Maybe you should have a look at the NAND_ROW_ADDR_3 flag?

The arm SMC pl353 controller operates in cmd phase and data phase.
In cmd phase it requires number of address cycles, hence we are using this
By reading from parameter page.
DOC: http://infocenter.arm.com/help/topic/com.arm.doc.ddi0380g/DDI0380G_smc_pl350_series_r2p1_trm.pdf
if you see table2-2 NAND AXI address setup, it describes the usage of cmd
and data phases.
If we remove this onfi_params, is there an alternative to write the number of address cycles filed in
Cmd phase register? 
Or can I use max value?, that means as per spec it supports max of 7 address cycles(it is a 3bit value).

Thanks,
Naga Sureshkumar Relli.
> 
> Thanks,
> Miquèl
> 
> >
> > Helmut
> >
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> 
> 
> 
> --
> Miquel Raynal, Bootlin (formerly Free Electrons) Embedded Linux and Kernel engineering
> https://bootlin.com