From nobody Thu Oct 9 01:13:14 2025 Received: from bali.collaboradmins.com (bali.collaboradmins.com [148.251.105.195]) (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 CE6C82561D9; Mon, 23 Jun 2025 12:00:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.251.105.195 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750680057; cv=none; b=UkKJ8pZ78x1Pefuf0B9S9VpEDq49DwMh52RuwyHdUtH3wNeiMNRLL7rPJlWoeyiP9ai+eZ7K2pDbOOkxr6s70qA1k95MEeJ9UJoYe/WFDBxRyRBSKSoF6cWWUD84nY9s+KCOJoxD3kCKhic5I8fRmrrgcSoHWlDucGaFMl2MQTM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750680057; c=relaxed/simple; bh=/qYS7j1Kjsx2bsMR5FO+759f8nIWeGhSxaDm1IPwegE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FAK2nPIfbNkmxLtmYC/nrLyFuhk7l9M3v0Jc2H/2FZx9X/U5y1Cb6OxKMrbjNdXkSLgdInXvMqX8vwbGxYOJ48SZosFMJPpKYzNdQwwIkIOCGFyJSmS3p/+9Mceja6qpRh/wk/WiVBqq4oV1ZyktsI3O0q+B5NSWcAlZ3CYrkr4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b=p/qIfElN; arc=none smtp.client-ip=148.251.105.195 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b="p/qIfElN" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1750680054; bh=/qYS7j1Kjsx2bsMR5FO+759f8nIWeGhSxaDm1IPwegE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=p/qIfElNqNCxByneAMRVW5sGcKmD3Kly9AN7VUhveOfi8j5yrI12ncftiBLskOUrU pNJo1q3TdlqLRbv+3pZrCZ43n7uC64IiMptqlF3+1/+Kp+VYjbxvy4TZZz2fCjgDC+ FPWAxtmC7pH8fD6FCd7bKT2eE3wZVD9JmRKRiYt1fktuagtuu1GRSYgQsG+/JHWyMc /zBk7elPV3wVmj3eqyunEj+MtV2fJNc1UewloZ6re0U2NeJcOkTKByDUdw3jpZzBCW 2zo2cP/g1auWWOb9fnoR6O7hu530BA0AtB/G9VXqRQu9iVqnDZ3zwb6mvxfKRshj1j 6uCrjzCYy4NVw== Received: from IcarusMOD.eternityproject.eu (2-237-20-237.ip236.fastwebnet.it [2.237.20.237]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: kholk11) by bali.collaboradmins.com (Postfix) with ESMTPSA id 557D317E1560; Mon, 23 Jun 2025 14:00:53 +0200 (CEST) From: AngeloGioacchino Del Regno To: sboyd@kernel.org Cc: robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, matthias.bgg@gmail.com, angelogioacchino.delregno@collabora.com, hsin-hsiung.wang@mediatek.com, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, kernel@collabora.com Subject: [PATCH v1 3/5] spmi: mtk-pmif: Keep spinlock until read is fully done Date: Mon, 23 Jun 2025 14:00:45 +0200 Message-ID: <20250623120047.108961-4-angelogioacchino.delregno@collabora.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250623120047.108961-1-angelogioacchino.delregno@collabora.com> References: <20250623120047.108961-1-angelogioacchino.delregno@collabora.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Move the spin unlocking to after reading the contents of the PMIF_SWINF_(x)_RDATA_31_0 register in pmif_spmi_read_cmd(): since this is the only register that we can read to get the data from all of the arbitered busses, a concurrent request for reading (especially on a busy arbiter) will show a race condition and a unexpected or corrupted value may be read. Doing the entire read sequence while spin locked guarantees that concurrent access to the arbiter doesn't happen. Signed-off-by: AngeloGioacchino Del Regno --- drivers/spmi/spmi-mtk-pmif.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/spmi/spmi-mtk-pmif.c b/drivers/spmi/spmi-mtk-pmif.c index 68f458587c67..9f416b231ab8 100644 --- a/drivers/spmi/spmi-mtk-pmif.c +++ b/drivers/spmi/spmi-mtk-pmif.c @@ -22,7 +22,7 @@ #define PMIF_CMD_EXT_REG 2 #define PMIF_CMD_EXT_REG_LONG 3 =20 -#define PMIF_DELAY_US 10 +#define PMIF_DELAY_US 2 #define PMIF_TIMEOUT_US (10 * 1000) =20 #define PMIF_CHAN_OFFSET 0x5 @@ -372,7 +372,6 @@ static int pmif_spmi_read_cmd(struct spmi_controller *c= trl, u8 opc, u8 sid, /* Send the command. */ cmd =3D (opc << 30) | (sid << 24) | ((len - 1) << 16) | addr; pmif_writel(arb, pbus, cmd, inf_reg->ch_send); - raw_spin_unlock_irqrestore(&pbus->lock, flags); =20 /* * Wait for Software Interface FSM state to be WFVLDCLR, @@ -382,13 +381,16 @@ static int pmif_spmi_read_cmd(struct spmi_controller = *ctrl, u8 opc, u8 sid, data, GET_SWINF(data) =3D=3D SWINF_WFVLDCLR, PMIF_DELAY_US, PMIF_TIMEOUT_US); if (ret < 0) { + raw_spin_unlock_irqrestore(&pbus->lock, flags); dev_err(&ctrl->dev, "failed to wait for SWINF_WFVLDCLR\n"); return ret; } =20 data =3D pmif_readl(arb, pbus, inf_reg->rdata); - memcpy(buf, &data, len); pmif_writel(arb, pbus, 1, inf_reg->ch_rdy); + raw_spin_unlock_irqrestore(&pbus->lock, flags); + + memcpy(buf, &data, len); =20 return 0; } --=20 2.49.0