From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.bootlin.com ([62.4.15.54]:45738 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725878AbeJBExh (ORCPT ); Tue, 2 Oct 2018 00:53:37 -0400 Date: Tue, 2 Oct 2018 00:13:28 +0200 From: Boris Brezillon To: Chris Packham Cc: Daniel Mack , Miquel Raynal , "linux-mtd@lists.infradead.org" , "stable@vger.kernel.org" Subject: Re: [PATCH v2] mtd: rawnand: marvell: check for RDY bits after enabling the IRQ Message-ID: <20181002001328.7f64ecbc@bbrezillon> In-Reply-To: References: <20181001234120.425ae1f5@bbrezillon> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: stable-owner@vger.kernel.org List-ID: On Mon, 1 Oct 2018 22:01:27 +0000 Chris Packham wrote: > On 02/10/18 10:41, Boris Brezillon wrote: > > On Mon, 1 Oct 2018 22:34:38 +0200 > > Boris Brezillon wrote: > > > >>> > >>> I'd previously tried readl() based on the same hunch. No change. > >>> > >>> I think my snippet above might be misleading. While a delay between > >>> readl_relaxed() and the if should not change the outcome, this is also a > >>> delay between marvell_nfc_enable_int() and marvell_nfc_disable_int() > >>> which is probably more significant. Sure enough if I move the delay to > >>> just before the marvell_nfc_disable_int() the error is not seen. > >> > >> AFAICT, your timeout always happens when waiting for RDREQ, not RDYM. > >> So maybe disabling MRDY too early has a side-effect on the RDREQ event. > > > > Can you try with this patch [1]? It should ensure that NDSR_RDY bits > > are cleared before starting an operation. > > > > [1]http://code.bulix.org/lgs30c-468205 > > > > No luck. I applied that on top of Daniel's and got the same result. > > One thing that does look promising is the following modification of > Daniel's patch[1]. Which moves the RDY check to before where the > interrupts are enabled. Except we still don't know why this is happening, and I'm not sure I want to take a fix without understanding why it does fix the problem. Also, it looks like complete() is not called until the RDDREQ, WRDREQ and WRCMDREQ are cleared in the interrupt handler [1], which is weird. Miquel, do you happen to remember why you had to do that? [1]https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/mtd/nand/raw/marvell_nand.c?h=v4.19-rc6#n689