From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C49CBC433DF for ; Thu, 11 Jun 2020 07:14:05 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 95825207D5 for ; Thu, 11 Jun 2020 07:14:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="JOZ55I5n" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 95825207D5 Authentication-Results: mail.kernel.org; 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Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jjHPH-00064R-MZ; Thu, 11 Jun 2020 07:13:47 +0000 Received: from relay4-d.mail.gandi.net ([217.70.183.196]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jjHPE-00063p-9s for linux-mtd@lists.infradead.org; Thu, 11 Jun 2020 07:13:45 +0000 X-Originating-IP: 91.224.148.103 Received: from xps13 (unknown [91.224.148.103]) (Authenticated sender: miquel.raynal@bootlin.com) by relay4-d.mail.gandi.net (Postfix) with ESMTPSA id 20389E0016; Thu, 11 Jun 2020 07:13:37 +0000 (UTC) Date: Thu, 11 Jun 2020 09:13:36 +0200 From: Miquel Raynal To: Sivaprakash Murugesan Subject: Re: [PATCH V2 2/2] mtd: rawnand: qcom: set BAM mode only if not set already Message-ID: <20200611091336.1f22ad55@xps13> In-Reply-To: <2abac8fb-28ac-5137-70cc-47cbd20613b7@codeaurora.org> References: <1591701056-3944-1-git-send-email-sivaprak@codeaurora.org> <1591701056-3944-3-git-send-email-sivaprak@codeaurora.org> <20200609160352.60cbad80@xps13> <2abac8fb-28ac-5137-70cc-47cbd20613b7@codeaurora.org> Organization: Bootlin X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200611_001344_476546_E596A3C7 X-CRM114-Status: GOOD ( 19.67 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peter.ujfalusi@ti.com, richard@nod.at, linux-mtd@lists.infradead.org, vigneshr@ti.com, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org SGkgU2l2YXByYWthc2gsCgpTaXZhcHJha2FzaCBNdXJ1Z2VzYW4gPHNpdmFwcmFrQGNvZGVhdXJv cmEub3JnPiB3cm90ZSBvbiBUaHUsIDExIEp1bgoyMDIwIDA5OjU3OjU5ICswNTMwOgoKPiBIaSBN aXF1ZWwsCj4gCj4gVGhhbmtzIGZvciB0aGUgcmV2aWV3Lgo+IAo+IE9uIDYvOS8yMDIwIDc6MzMg UE0sIE1pcXVlbCBSYXluYWwgd3JvdGU6Cj4gPiBIaSBTaXZhcHJha2FzaCwKPiA+Cj4gPiBTaXZh cHJha2FzaCBNdXJ1Z2VzYW4gPHNpdmFwcmFrQGNvZGVhdXJvcmEub3JnPiB3cm90ZSBvbiBUdWUs ICA5IEp1bgo+ID4gMjAyMCAxNjo0MDo1NiArMDUzMDoKPiA+ICAKPiA+PiBCQU0gbW9kZSBpcyBz ZXQgYnkgd3JpdGluZyBCQU1fTU9ERV9FTiBiaXQgb24gTkFORF9DVFJMIHJlZ2lzdGVyLgo+ID4+ IE5BTkRfQ1RSTCBpcyBhbiBvcGVyYXRpb25hbCByZWdpc3RlciBhbmQgaW4gQkFNIG1vZGUgb3Bl cmF0aW9uYWwKPiA+PiByZWdpc3RlcnMgYXJlIHJlYWQgb25seS4KPiA+Pgo+ID4+IFNvLCBiZWZv cmUgd3JpdGluZyBpbnRvIE5BTkRfQ1RSTCByZWdpc3RlciBjaGVjayBpZiBCQU0gbW9kZSBpcyBh bHJlYWR5Cj4gPj4gZW5hYmxlZCBieSBib290bG9hZGVyLCBhbmQgc2V0IEJBTSBtb2RlIG9ubHkg aWYgaXQgaXMgbm90IHNldCBhbHJlYWR5Lgo+ID4+Cj4gPj4gU2lnbmVkLW9mZi1ieTogU2l2YXBy YWthc2ggTXVydWdlc2FuIDxzaXZhcHJha0Bjb2RlYXVyb3JhLm9yZz4KPiA+PiAtLS0KPiA+PiAg IGRyaXZlcnMvbXRkL25hbmQvcmF3L3Fjb21fbmFuZGMuYyB8IDkgKysrKysrKystCj4gPj4gICAx IGZpbGUgY2hhbmdlZCwgOCBpbnNlcnRpb25zKCspLCAxIGRlbGV0aW9uKC0pCj4gPj4KPiA+PiBk aWZmIC0tZ2l0IGEvZHJpdmVycy9tdGQvbmFuZC9yYXcvcWNvbV9uYW5kYy5jIGIvZHJpdmVycy9t dGQvbmFuZC9yYXcvcWNvbV9uYW5kYy5jCj4gPj4gaW5kZXggZTBhZmEyYy4uNzc0MDA1OSAxMDA2 NDQKPiA+PiAtLS0gYS9kcml2ZXJzL210ZC9uYW5kL3Jhdy9xY29tX25hbmRjLmMKPiA+PiArKysg Yi9kcml2ZXJzL210ZC9uYW5kL3Jhdy9xY29tX25hbmRjLmMKPiA+PiBAQCAtMjc3OSw3ICsyNzc5 LDE0IEBAIHN0YXRpYyBpbnQgcWNvbV9uYW5kY19zZXR1cChzdHJ1Y3QgcWNvbV9uYW5kX2NvbnRy b2xsZXIgKm5hbmRjKQo+ID4+ICAgCS8qIGVuYWJsZSBBRE0gb3IgQkFNIERNQSAqLwo+ID4+ICAg CWlmIChuYW5kYy0+cHJvcHMtPmlzX2JhbSkgewo+ID4+ICAgCQluYW5kX2N0cmwgPSBuYW5kY19y ZWFkKG5hbmRjLCBOQU5EX0NUUkwpOwo+ID4+IC0JCW5hbmRjX3dyaXRlKG5hbmRjLCBOQU5EX0NU UkwsIG5hbmRfY3RybCB8IEJBTV9NT0RFX0VOKTsKPiA+PiArCQkvKiBOQU5EX0NUUkwgaXMgYW4g b3BlcmF0aW9uYWwgcmVnaXN0ZXJzLCBhbmQgQ1BVCj4gPj4gKwkJICogYWNjZXNzIHRvIG9wZXJh dGlvbmFsIHJlZ2lzdGVycyBhcmUgcmVhZCBvbmx5Cj4gPj4gKwkJICogaW4gQkFNIG1vZGUuIFNv IHVwZGF0ZSB0aGUgTkFORF9DVFJMIHJlZ2lzdGVyCj4gPj4gKwkJICogb25seSBpZiBpdCBpcyBu b3QgaW4gQkFNIG1vZGUuIEluIG1vc3QgY2FzZXMgQkFNCj4gPj4gKwkJICogbW9kZSB3aWxsIGJl IGVuYWJsZWQgaW4gYm9vdGxvYWRlcgo+ID4+ICsJCSAqLwo+ID4+ICsJCWlmICghKG5hbmRfY3Ry bCB8IEJBTV9NT0RFX0VOKSkKPiA+PiArCQkJbmFuZGNfd3JpdGUobmFuZGMsIE5BTkRfQ1RSTCwg bmFuZF9jdHJsIHwgQkFNX01PREVfRU4pOwo+ID4+ICAgCX0gZWxzZSB7Cj4gPj4gICAJCW5hbmRj X3dyaXRlKG5hbmRjLCBOQU5EX0ZMQVNIX0NISVBfU0VMRUNULCBETV9FTik7Cj4gPj4gICAJfSAg Cj4gPiBEb2VzIHRoaXMgY3VycmVudGx5IHByb2R1Y2VzIGFuIGlzc3VlIGF0IHJ1bnRpbWU/Cj4g Pgo+ID4gSWYgeWVzLCB5b3Ugc2hvdWxkIGhhdmUgYSBGaXhlcy9DQzogc3RhYmxlIHBhaXIgb2Yg dGFncy4KPiA+Cj4gPiBBbHNvLCB3aGF0IGlzIEJBTSBtb2RlPyBQbGVhc2UgdGVsbCB1cyBpbiB0 aGUgY29tbWl0IGxvZy4gIAo+IAo+IEN1cnJlbnRseSB0aGlzIGlzIG5vdCBjYXVzaW5nIGFueSBp c3N1ZSBvbiBydW4gdGltZS4KPiAKPiBUaGUgd3JpdGVzIHRvIHRoaXMgcmVnaXN0ZXIgaXMgc2ls ZW50bHkgaWdub3JlZC4KPiAKPiBIb3dldmVyLCB0aGlzIGNvdWxkIGJlIGFuIGlzc3VlIGluIGZ1 dHVyZSBIYXJkd2FyZSBkZXNpZ25zLgo+IAo+IEJBTSBpcyB0aGUgRE1BIGVuZ2luZSBvbiBRQ09N IElQUSBwbGF0Zm9ybXMsIHN1cmUgd2lsbCBleHBsYWluIHRoaXMKPiAKPiBtb2RlIGluIG5leHQg cGF0Y2hzZXQuCgpJIGRvbid0IGxpa2Ugc28gbXVjaCB0aGUgaWRlYSBvZiBETUEgYmVpbmcgZW5h YmxlZCBieSB0aGUgQm9vdGxvYWRlciBvcgpub3QsIHRoaXMgaXMgc29tZXRoaW5nIHRoYXQgc2hv dWxkIG5lZWQgdG8gYmUgZml4ZWQuCgoKVGhhbmtzLApNaXF1w6hsCgpfX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KTGludXggTVREIGRpc2N1c3Np b24gbWFpbGluZyBsaXN0Cmh0dHA6Ly9saXN0cy5pbmZyYWRlYWQub3JnL21haWxtYW4vbGlzdGlu Zm8vbGludXgtbXRkLwo= From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B7015C433DF for ; Thu, 11 Jun 2020 07:13:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8B254207D5 for ; Thu, 11 Jun 2020 07:13:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726620AbgFKHNl convert rfc822-to-8bit (ORCPT ); Thu, 11 Jun 2020 03:13:41 -0400 Received: from relay4-d.mail.gandi.net ([217.70.183.196]:47251 "EHLO relay4-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726375AbgFKHNk (ORCPT ); Thu, 11 Jun 2020 03:13:40 -0400 X-Originating-IP: 91.224.148.103 Received: from xps13 (unknown [91.224.148.103]) (Authenticated sender: miquel.raynal@bootlin.com) by relay4-d.mail.gandi.net (Postfix) with ESMTPSA id 20389E0016; Thu, 11 Jun 2020 07:13:37 +0000 (UTC) Date: Thu, 11 Jun 2020 09:13:36 +0200 From: Miquel Raynal To: Sivaprakash Murugesan Cc: richard@nod.at, vigneshr@ti.com, peter.ujfalusi@ti.com, linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH V2 2/2] mtd: rawnand: qcom: set BAM mode only if not set already Message-ID: <20200611091336.1f22ad55@xps13> In-Reply-To: <2abac8fb-28ac-5137-70cc-47cbd20613b7@codeaurora.org> References: <1591701056-3944-1-git-send-email-sivaprak@codeaurora.org> <1591701056-3944-3-git-send-email-sivaprak@codeaurora.org> <20200609160352.60cbad80@xps13> <2abac8fb-28ac-5137-70cc-47cbd20613b7@codeaurora.org> Organization: Bootlin X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Sivaprakash, Sivaprakash Murugesan wrote on Thu, 11 Jun 2020 09:57:59 +0530: > Hi Miquel, > > Thanks for the review. > > On 6/9/2020 7:33 PM, Miquel Raynal wrote: > > Hi Sivaprakash, > > > > Sivaprakash Murugesan wrote on Tue, 9 Jun > > 2020 16:40:56 +0530: > > > >> BAM mode is set by writing BAM_MODE_EN bit on NAND_CTRL register. > >> NAND_CTRL is an operational register and in BAM mode operational > >> registers are read only. > >> > >> So, before writing into NAND_CTRL register check if BAM mode is already > >> enabled by bootloader, and set BAM mode only if it is not set already. > >> > >> Signed-off-by: Sivaprakash Murugesan > >> --- > >> drivers/mtd/nand/raw/qcom_nandc.c | 9 ++++++++- > >> 1 file changed, 8 insertions(+), 1 deletion(-) > >> > >> diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c > >> index e0afa2c..7740059 100644 > >> --- a/drivers/mtd/nand/raw/qcom_nandc.c > >> +++ b/drivers/mtd/nand/raw/qcom_nandc.c > >> @@ -2779,7 +2779,14 @@ static int qcom_nandc_setup(struct qcom_nand_controller *nandc) > >> /* enable ADM or BAM DMA */ > >> if (nandc->props->is_bam) { > >> nand_ctrl = nandc_read(nandc, NAND_CTRL); > >> - nandc_write(nandc, NAND_CTRL, nand_ctrl | BAM_MODE_EN); > >> + /* NAND_CTRL is an operational registers, and CPU > >> + * access to operational registers are read only > >> + * in BAM mode. So update the NAND_CTRL register > >> + * only if it is not in BAM mode. In most cases BAM > >> + * mode will be enabled in bootloader > >> + */ > >> + if (!(nand_ctrl | BAM_MODE_EN)) > >> + nandc_write(nandc, NAND_CTRL, nand_ctrl | BAM_MODE_EN); > >> } else { > >> nandc_write(nandc, NAND_FLASH_CHIP_SELECT, DM_EN); > >> } > > Does this currently produces an issue at runtime? > > > > If yes, you should have a Fixes/CC: stable pair of tags. > > > > Also, what is BAM mode? Please tell us in the commit log. > > Currently this is not causing any issue on run time. > > The writes to this register is silently ignored. > > However, this could be an issue in future Hardware designs. > > BAM is the DMA engine on QCOM IPQ platforms, sure will explain this > > mode in next patchset. I don't like so much the idea of DMA being enabled by the Bootloader or not, this is something that should need to be fixed. Thanks, Miquèl