From nobody Wed Oct 8 04:09:24 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 C4AD72E3AFD; Thu, 3 Jul 2025 11:58:47 +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=1751543929; cv=none; b=TGYxs+4/q1JU7ElTQy3muLt1Og3MOmPgU97F0v43244Q7QLcHNEsjgY6oPXU+8xG/6htl4cgY+1LCWxsElXfu9p5mmj6l1OfJKd1TiNgG4YjyX2HQTeYxYqg3JKrGIUmBzRJ+UZoGkG+BzqG6sXQq4s27dxAfOuzk3zZN92lJEQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751543929; c=relaxed/simple; bh=dx1glT6Vu/pVjckglIR4Zn3O8xpjDZblhDOnXlLKFVg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=pFWQmIjN+r5pcu5/EwSYtpbxANOmNiYxY81i8N+t5UyDKzNxwGxtIPR7CXSkAKALjvS66ASxyV261SOG5bdOlNFqiY/UhQu0Vz3csrSaFN7S4SIeptlZb/8hbIoEWy2kh5XrJPOdcShrpjhye7a5B7HUsAzEWr4m5qtRSsNW9HQ= 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=NiRJQmuB; 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="NiRJQmuB" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1751543926; bh=dx1glT6Vu/pVjckglIR4Zn3O8xpjDZblhDOnXlLKFVg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NiRJQmuBmuHelEDNzzPj4DHkzEi2wxnlw2Hcyc5Oh2awsVKuIEZOocs/dv9aSPNRt 54am/71O0iNDMkOqt3psfzcMHcbHmqkCHhxGFmvewRp3khBzGwnFqBGuO6HerPQCvY S7gboUn5Q8u9TGDZOUagNgBOoy5v8z8t8+gMEwJ4Lt5uYz/qzKfXMkhoMCV/lr+QbF qkKvmXvTMsAoI89W41enBaFjyvSonDbmIcYKj6eDKFzTjyRShZqs+AeWcZJGUeTK0R oDXuP1jlduk6OM/2uoWzK2WFAiN4FvDdcQv/AGwNdLswS3l7W8OMIvlOTH0Ae+HMpt diThZqF3UnPWA== 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 5A81317E0636; Thu, 3 Jul 2025 13:58:45 +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, =?UTF-8?q?N=C3=ADcolas=20F=2E=20R=2E=20A=2E=20Prado?= Subject: [PATCH v2 3/5] spmi: mtk-pmif: Keep spinlock until read is fully done Date: Thu, 3 Jul 2025 13:58:26 +0200 Message-ID: <20250703115828.118425-4-angelogioacchino.delregno@collabora.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250703115828.118425-1-angelogioacchino.delregno@collabora.com> References: <20250703115828.118425-1-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-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable 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. Reviewed-by: N=C3=ADcolas F. R. A. Prado Signed-off-by: AngeloGioacchino Del Regno Reviewed-by: Chen-Yu Tsai --- 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