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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2E662C433EF for ; Mon, 4 Oct 2021 13:09:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1439E61BD3 for ; Mon, 4 Oct 2021 13:09:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235719AbhJDNLF (ORCPT ); Mon, 4 Oct 2021 09:11:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:39512 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235609AbhJDNIo (ORCPT ); Mon, 4 Oct 2021 09:08:44 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 588E261A58; Mon, 4 Oct 2021 13:02:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1633352558; bh=JykexGAPNf0ofLwIzVrFG6D+y1QB9Y5AeNY+sL7dlec=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QCviMaKVfh5p/tN1Tb1BAWQIvfv5hz0+IISV7P9AoMpofpb/fLd+BZ3TeYaxH1kF3 8Xd7mDv1FSTs5Mtovcy8nF42NG+RMwb/qadIJX2wVXWdnw1WQd2U2VuBulrcoDVlOb 6cxcqbqXV92V0ZjrWFDTR6sNw8zu6/w381fw2BsQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jesper Nilsson , "David S. Miller" , Sasha Levin Subject: [PATCH 4.19 34/95] net: stmmac: allow CSR clock of 300MHz Date: Mon, 4 Oct 2021 14:52:04 +0200 Message-Id: <20211004125034.683950635@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211004125033.572932188@linuxfoundation.org> References: <20211004125033.572932188@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jesper Nilsson [ Upstream commit 08dad2f4d541fcfe5e7bfda72cc6314bbfd2802f ] The Synopsys Ethernet IP uses the CSR clock as a base clock for MDC. The divisor used is set in the MAC_MDIO_Address register field CR (Clock Rate) The divisor is there to change the CSR clock into a clock that falls below the IEEE 802.3 specified max frequency of 2.5MHz. If the CSR clock is 300MHz, the code falls back to using the reset value in the MAC_MDIO_Address register, as described in the comment above this code. However, 300MHz is actually an allowed value and the proper divider can be estimated quite easily (it's just 1Hz difference!) A CSR frequency of 300MHz with the maximum clock rate value of 0x5 (STMMAC_CSR_250_300M, a divisor of 124) gives somewhere around ~2.42MHz which is below the IEEE 802.3 specified maximum. For the ARTPEC-8 SoC, the CSR clock is this problematic 300MHz, and unfortunately, the reset-value of the MAC_MDIO_Address CR field is 0x0. This leads to a clock rate of zero and a divisor of 42, and gives an MDC frequency of ~7.14MHz. Allow CSR clock of 300MHz by making the comparison inclusive. Signed-off-by: Jesper Nilsson Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index af59761ddfa0..064e13bd2c8b 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -227,7 +227,7 @@ static void stmmac_clk_csr_set(struct stmmac_priv *priv) priv->clk_csr = STMMAC_CSR_100_150M; else if ((clk_rate >= CSR_F_150M) && (clk_rate < CSR_F_250M)) priv->clk_csr = STMMAC_CSR_150_250M; - else if ((clk_rate >= CSR_F_250M) && (clk_rate < CSR_F_300M)) + else if ((clk_rate >= CSR_F_250M) && (clk_rate <= CSR_F_300M)) priv->clk_csr = STMMAC_CSR_250_300M; } -- 2.33.0