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 418B9309DA0; Mon, 13 Oct 2025 15:30:05 +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=1760369405; cv=none; b=r+iH6MGLI/bvnuGdSgrahq9C2+OONvBQvnYl5RqXLmfbIC91O/t8GkD9dEKr+skFCWodeSDVFMp0YGb+QpDt735QqT3sOlJeAZmGAoaw4lXoIWTPysnisSNmD/viXgqGpJJXBn43NZ2yJSchX5Cqkgw4kw03wq7h9usw62pP1d8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760369405; c=relaxed/simple; bh=2JCPvpq5MqdDJ6dQlvYDKz+J392iaQjbpr15JaIelTE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=onPT5Pf8hX4m7pHMUhbrDBXt+mMWKe+M1wPthvJCtnYDLvk/D6bJx14ZFE2mDGdrBirnYwI3foAhNHZRzK/ddmiKEucgD1TQ5BnGpSlYk7YJUPqfxWS77W8A82lnT6umEWbuTEeYCP8p/RqZQKXoqCFh6bTxDRgoKUeIaHzdP4c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=dtdHG3Bt; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="dtdHG3Bt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B97E0C4CEE7; Mon, 13 Oct 2025 15:30:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1760369405; bh=2JCPvpq5MqdDJ6dQlvYDKz+J392iaQjbpr15JaIelTE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dtdHG3BtvKVAJajH7S4avsmfrYM4t2Fnvc5YMS9iO7q/E65hGyEPJASJJR/RltPVF NDMQY9JmN/RKvkGKWu3JC4+Z3jddS5+9YFMG9sByo91uYTx91T2uNdNBmhV0xtv99u bNOHu0wfbXF9DCcFUUJJa61zCvMyDRdFcduxMSA8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Troy Mitchell , Aurelien Jarno , Wolfram Sang , Sasha Levin Subject: [PATCH 6.17 201/563] i2c: spacemit: remove stop function to avoid bus error Date: Mon, 13 Oct 2025 16:41:02 +0200 Message-ID: <20251013144418.568740203@linuxfoundation.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251013144411.274874080@linuxfoundation.org> References: <20251013144411.274874080@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.17-stable review patch. If anyone has any objections, please let me know. ------------------ From: Troy Mitchell [ Upstream commit 445522fe7aad6131b2747ae8c76f77266054cd84 ] Previously, STOP handling was split into two separate steps: 1) clear TB/STOP/START/ACK bits 2) issue STOP by calling spacemit_i2c_stop() This left a small window where the control register was updated twice, which can confuse the controller. While this race has not been observed with interrupt-driven transfers, it reliably causes bus errors in PIO mode. Inline the STOP sequence into the IRQ handler and ensure that control register bits are updated atomically in a single writel(). Fixes: 5ea558473fa31 ("i2c: spacemit: add support for SpacemiT K1 SoC") Signed-off-by: Troy Mitchell Reviewed-by: Aurelien Jarno Signed-off-by: Wolfram Sang Signed-off-by: Sasha Levin --- drivers/i2c/busses/i2c-k1.c | 26 +++++++------------------- 1 file changed, 7 insertions(+), 19 deletions(-) diff --git a/drivers/i2c/busses/i2c-k1.c b/drivers/i2c/busses/i2c-k1.c index ee08811f4087c..84f132d0504dc 100644 --- a/drivers/i2c/busses/i2c-k1.c +++ b/drivers/i2c/busses/i2c-k1.c @@ -267,19 +267,6 @@ static void spacemit_i2c_start(struct spacemit_i2c_dev *i2c) writel(val, i2c->base + SPACEMIT_ICR); } -static void spacemit_i2c_stop(struct spacemit_i2c_dev *i2c) -{ - u32 val; - - val = readl(i2c->base + SPACEMIT_ICR); - val |= SPACEMIT_CR_STOP | SPACEMIT_CR_ALDIE | SPACEMIT_CR_TB; - - if (i2c->read) - val |= SPACEMIT_CR_ACKNAK; - - writel(val, i2c->base + SPACEMIT_ICR); -} - static int spacemit_i2c_xfer_msg(struct spacemit_i2c_dev *i2c) { unsigned long time_left; @@ -412,7 +399,6 @@ static irqreturn_t spacemit_i2c_irq_handler(int irq, void *devid) val = readl(i2c->base + SPACEMIT_ICR); val &= ~(SPACEMIT_CR_TB | SPACEMIT_CR_ACKNAK | SPACEMIT_CR_STOP | SPACEMIT_CR_START); - writel(val, i2c->base + SPACEMIT_ICR); switch (i2c->state) { case SPACEMIT_STATE_START: @@ -429,14 +415,16 @@ static irqreturn_t spacemit_i2c_irq_handler(int irq, void *devid) } if (i2c->state != SPACEMIT_STATE_IDLE) { + val |= SPACEMIT_CR_TB | SPACEMIT_CR_ALDIE; + if (spacemit_i2c_is_last_msg(i2c)) { /* trigger next byte with stop */ - spacemit_i2c_stop(i2c); - } else { - /* trigger next byte */ - val |= SPACEMIT_CR_ALDIE | SPACEMIT_CR_TB; - writel(val, i2c->base + SPACEMIT_ICR); + val |= SPACEMIT_CR_STOP; + + if (i2c->read) + val |= SPACEMIT_CR_ACKNAK; } + writel(val, i2c->base + SPACEMIT_ICR); } err_out: -- 2.51.0