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 X-Spam-Level: X-Spam-Status: No, score=-20.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D5B5AC433FE for ; Thu, 23 Sep 2021 03:39:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C04B761152 for ; Thu, 23 Sep 2021 03:39:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239304AbhIWDkz (ORCPT ); Wed, 22 Sep 2021 23:40:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:41006 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239126AbhIWDkR (ORCPT ); Wed, 22 Sep 2021 23:40:17 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7507261038; Thu, 23 Sep 2021 03:38:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1632368326; bh=1VzKd4lDYzDCQBnSL+/uC9/qu21edJfqtQJgQ/w2+VU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=V9GGcmHVan5mPxoUJISOjy8bTNSDWPADr6WXpDUnOjGCF3vG/6y9PE2Tqn44XrsE5 MVV+ss5rY8h6hCeHFTg+rjK2kCljZod5zYiiF/RkuN5gKRe8L0FDyB5Dmzp83cJK0F UXSCe7oXm6kb2fUXjL6SfCCgo8o9txaPjfl96xZqyEtQnz9LQ0rwZVFQ8lY6dlSctI neXZP/SMV4c1DyogaFhTE/7JaKNn5Fju0IHrs18GejnQ7Gjd7egi9s5OJ+lZTDj1Ue OM7IFj16hmy3Ny8GPBwfeVOvmDg1o/+GGOiIGCoajfXYdEaoM8p6jJuv17aGo45xJU QX6IGPF25qghA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jesper Nilsson , "David S . Miller" , Sasha Levin , peppe.cavallaro@st.com, alexandre.torgue@foss.st.com, joabreu@synopsys.com, kuba@kernel.org, mcoquelin.stm32@gmail.com, netdev@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org Subject: [PATCH AUTOSEL 5.10 04/26] net: stmmac: allow CSR clock of 300MHz Date: Wed, 22 Sep 2021 23:38:17 -0400 Message-Id: <20210923033839.1421034-4-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210923033839.1421034-1-sashal@kernel.org> References: <20210923033839.1421034-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@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 3134f7e669f8..6133b2fe8a78 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -226,7 +226,7 @@ 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; } -- 2.30.2