From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 39B51336896 for ; Fri, 8 May 2026 21:18:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778275099; cv=none; b=dlhoWiEsCZYKrs6Ly8nNx1O/TUWRydceX1WVUbe2Mb3odlQp+X5bwF053nKG1Ft1YNwBRrBZ60lefZle0XJVUYINal8W32tUfWdSCpq1kJETOhgtSblC4xy9argG6zYSLL7v5HiVV+RgAcP00b1wPVjU1TkBbjhsy63TpjwhYjE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778275099; c=relaxed/simple; bh=xBgJyvA/bM47mnjHadGw0FOuT/Z4Gf7GGt1qER6NKpI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bfUsiReILwKIipF0MU5ZeUhCOkn18dAlmLrQvEyNuQEOEqi3YV8hhgj0dr722evo+g9HYXHZcMeb2Ybb1gaJDXsuR8k5hG+5EkbxxiqYQ0FQMQ4yRQupH7wb1baqIFd3cS0EKJjUY3uJrSai1hAXY4YfwWyNM8oBhC3VXLldaMk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bQjUW8W5; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="bQjUW8W5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4DD3AC2BCB0; Fri, 8 May 2026 21:18:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778275098; bh=xBgJyvA/bM47mnjHadGw0FOuT/Z4Gf7GGt1qER6NKpI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bQjUW8W5KMVUdDTt4GoUMQph/PnDMGj1vqI33p59jKRJSJjfrJeHX7fgjdrWk7ZQp gcw/j9yHqv9bgGDpqfJvug0CpOilk9SuP72C9MfKdPcqzFxnXOzjVUgvLGmTpxjCbS oCm2m4I9hy2L2b1lnw5q9RLeE9mRpgXzK/zgG4d/kMV8RgVooy1zPJZByjpWHQYNtb YSBTd9K+3usPRzXdJU823TWvikZVLmV7pxnmsDfxZforadxXWl60awpMSC2GfGq+uU 2UjyRgHQ2asyMANJKtQEMt/9T1W0pkfOnHNXVQjz/OWXJ+6qZAZddqLmvMs9rtW1gl L2rJ5csQEBLMg== From: Sasha Levin To: stable@vger.kernel.org Cc: Sanjaikumar V S , Hendrik Donner , "Pratyush Yadav (Google)" , Sasha Levin Subject: [PATCH 5.15.y] mtd: spi-nor: sst: Fix write enable before AAI sequence Date: Fri, 8 May 2026 17:18:16 -0400 Message-ID: <20260508211816.1960968-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026050406-deputize-unengaged-f5c5@gregkh> References: <2026050406-deputize-unengaged-f5c5@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Sanjaikumar V S [ Upstream commit a0f64241d3566a49c0a9b33ba7ae458ae22003a9 ] When writing to SST flash starting at an odd address, a single byte is first programmed using the byte program (BP) command. After this operation completes, the flash hardware automatically clears the Write Enable Latch (WEL) bit. If an AAI (Auto Address Increment) word program sequence follows, it requires WEL to be set. Without re-enabling writes, the AAI sequence fails. Add spi_nor_write_enable() after the odd-address byte program when more data needs to be written. Use a local boolean for clarity. Fixes: b199489d37b2 ("mtd: spi-nor: add the framework for SPI NOR") Cc: stable@vger.kernel.org Signed-off-by: Sanjaikumar V S Tested-by: Hendrik Donner Reviewed-by: Hendrik Donner Signed-off-by: Pratyush Yadav (Google) [ kept inline `nor->program_opcode = SPINOR_OP_BP;` ] Signed-off-by: Sasha Levin --- drivers/mtd/spi-nor/sst.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/mtd/spi-nor/sst.c b/drivers/mtd/spi-nor/sst.c index 980f4c09c91de..4c970c33957a3 100644 --- a/drivers/mtd/spi-nor/sst.c +++ b/drivers/mtd/spi-nor/sst.c @@ -112,6 +112,8 @@ static int sst_write(struct mtd_info *mtd, loff_t to, size_t len, /* Start write from odd address. */ if (to % 2) { + bool needs_write_enable = (len > 1); + nor->program_opcode = SPINOR_OP_BP; /* write one byte. */ @@ -125,6 +127,17 @@ static int sst_write(struct mtd_info *mtd, loff_t to, size_t len, to++; actual++; + + /* + * Byte program clears the write enable latch. If more + * data needs to be written using the AAI sequence, + * re-enable writes. + */ + if (needs_write_enable) { + ret = spi_nor_write_enable(nor); + if (ret) + goto out; + } } /* Write out most of the data here. */ -- 2.53.0