From patchwork Thu Jul 30 18:26:19 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicolas Saenz Julienne X-Patchwork-Id: 11693521 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D0F48912 for ; Thu, 30 Jul 2020 18:26:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BFE4922CB1 for ; Thu, 30 Jul 2020 18:26:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730023AbgG3S0f (ORCPT ); Thu, 30 Jul 2020 14:26:35 -0400 Received: from mx2.suse.de ([195.135.220.15]:50562 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726343AbgG3S0e (ORCPT ); Thu, 30 Jul 2020 14:26:34 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id DF4CDABCE; Thu, 30 Jul 2020 18:26:44 +0000 (UTC) From: Nicolas Saenz Julienne To: Nicolas Saenz Julienne , Florian Fainelli , Ray Jui , Scott Branden , bcm-kernel-feedback-list@broadcom.com, Eric Anholt , Stefan Wahren , Matthias Brugger Cc: pbrobinson@gmail.com, kernel-list@raspberrypi.com, Nathan Chancellor , Michael Turquette , Stephen Boyd , linux-clk@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] clk: bcm2835: Do not use prediv with bcm2711's PLLs Date: Thu, 30 Jul 2020 20:26:19 +0200 Message-Id: <20200730182619.23246-1-nsaenzjulienne@suse.de> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Sender: linux-clk-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org Contrary to previous SoCs, bcm2711 doesn't have a prescaler in the PLL feedback loop. Bypass it by zeroing fb_prediv_mask when running on bcm2711. Note that, since the prediv configuration bits were re-purposed, this was triggering miscalculations on all clocks hanging from the VPU clock, notably the aux UART, making its output unintelligible. Fixes: 42de9ad400af ("clk: bcm2835: Add BCM2711_CLOCK_EMMC2 support") Reported-by: Nathan Chancellor Signed-off-by: Nicolas Saenz Julienne Tested-by: Nathan Chancellor Reviewed-by: Florian Fainelli --- Changes since v1: - Previous approach broken. Check if running on bcm2711 upon using fb_prediv_mask. FYI relevant discussion with RPi engineers: https://github.com/raspberrypi/firmware/issues/1435#issuecomment-666242077 drivers/clk/bcm/clk-bcm2835.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c index 027eba31f793..3439bc65bb4e 100644 --- a/drivers/clk/bcm/clk-bcm2835.c +++ b/drivers/clk/bcm/clk-bcm2835.c @@ -314,6 +314,7 @@ struct bcm2835_cprman { struct device *dev; void __iomem *regs; spinlock_t regs_lock; /* spinlock for all clocks */ + unsigned int soc; /* * Real names of cprman clock parents looked up through @@ -526,6 +527,20 @@ static int bcm2835_pll_is_on(struct clk_hw *hw) A2W_PLL_CTRL_PRST_DISABLE; } +static u32 bcm2835_pll_get_prediv_mask(struct bcm2835_cprman *cprman, + const struct bcm2835_pll_data *data) +{ + /* + * On BCM2711 there isn't a pre-divisor available in the PLL feedback + * loop. Bits 13:14 of ANA1 (PLLA,PLLB,PLLC,PLLD) have been re-purposed + * for to for VCO RANGE bits. + */ + if (cprman->soc & SOC_BCM2711) + return 0; + + return data->ana->fb_prediv_mask; +} + static void bcm2835_pll_choose_ndiv_and_fdiv(unsigned long rate, unsigned long parent_rate, u32 *ndiv, u32 *fdiv) @@ -583,7 +598,7 @@ static unsigned long bcm2835_pll_get_rate(struct clk_hw *hw, ndiv = (a2wctrl & A2W_PLL_CTRL_NDIV_MASK) >> A2W_PLL_CTRL_NDIV_SHIFT; pdiv = (a2wctrl & A2W_PLL_CTRL_PDIV_MASK) >> A2W_PLL_CTRL_PDIV_SHIFT; using_prediv = cprman_read(cprman, data->ana_reg_base + 4) & - data->ana->fb_prediv_mask; + bcm2835_pll_get_prediv_mask(cprman, data); if (using_prediv) { ndiv *= 2; @@ -666,6 +681,7 @@ static int bcm2835_pll_set_rate(struct clk_hw *hw, struct bcm2835_pll *pll = container_of(hw, struct bcm2835_pll, hw); struct bcm2835_cprman *cprman = pll->cprman; const struct bcm2835_pll_data *data = pll->data; + u32 prediv_mask = bcm2835_pll_get_prediv_mask(cprman, data); bool was_using_prediv, use_fb_prediv, do_ana_setup_first; u32 ndiv, fdiv, a2w_ctl; u32 ana[4]; @@ -683,7 +699,7 @@ static int bcm2835_pll_set_rate(struct clk_hw *hw, for (i = 3; i >= 0; i--) ana[i] = cprman_read(cprman, data->ana_reg_base + i * 4); - was_using_prediv = ana[1] & data->ana->fb_prediv_mask; + was_using_prediv = ana[1] & prediv_mask; ana[0] &= ~data->ana->mask0; ana[0] |= data->ana->set0; @@ -693,10 +709,10 @@ static int bcm2835_pll_set_rate(struct clk_hw *hw, ana[3] |= data->ana->set3; if (was_using_prediv && !use_fb_prediv) { - ana[1] &= ~data->ana->fb_prediv_mask; + ana[1] &= ~prediv_mask; do_ana_setup_first = true; } else if (!was_using_prediv && use_fb_prediv) { - ana[1] |= data->ana->fb_prediv_mask; + ana[1] |= prediv_mask; do_ana_setup_first = false; } else { do_ana_setup_first = true; @@ -2262,6 +2278,7 @@ static int bcm2835_clk_probe(struct platform_device *pdev) platform_set_drvdata(pdev, cprman); cprman->onecell.num = asize; + cprman->soc = pdata->soc; hws = cprman->onecell.hws; for (i = 0; i < asize; i++) {