From patchwork Tue Jun 13 08:36:25 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Frank Oltmanns X-Patchwork-Id: 13278158 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1D69EC77B7A for ; Tue, 13 Jun 2023 08:36:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241352AbjFMIgz (ORCPT ); Tue, 13 Jun 2023 04:36:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44560 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239393AbjFMIgx (ORCPT ); Tue, 13 Jun 2023 04:36:53 -0400 Received: from mout-p-202.mailbox.org (mout-p-202.mailbox.org [80.241.56.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 49587171D; Tue, 13 Jun 2023 01:36:47 -0700 (PDT) Received: from smtp2.mailbox.org (smtp2.mailbox.org [IPv6:2001:67c:2050:b231:465::2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-384) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mout-p-202.mailbox.org (Postfix) with ESMTPS id 4QgMNX092sz9sTt; Tue, 13 Jun 2023 10:36:44 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oltmanns.dev; s=MBO0001; t=1686645404; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=VrLmhksuKVuR06TD0+BUnlxKpggr1/sz/Cz0h1//L8s=; b=Vn9AAUwZtb+2x7aHjLSfk3YCkuxQKW5xymxW/Z+3LwyDyDIG8d5wdgov0/ug1qt1Fw4OUd KRovHYh4Cf9DicZc3sKgf3Qhc2uForzTLMoz4XbX2iI0qRF873r8rCBgfXV+VqvH+jqA0f glGUlNgP7ijupRHJaq09IREqfO7HH7dBVepSoVb+Yu7Is1U6fnD4Q6G1TSUDo1+XkM+TPY 4kxsxOtePM4hNKE07pE1U2fwMpM4yswIIvdmtdUvw41ldMxD/lvTfeloXYU+GLiQZDU7kI 08v7oEIsTg1NDL04YCdVRZiNczUceAbkrgfKftsMoca1oteZE/kYuIQQ89Jwgw== From: Frank Oltmanns To: Michael Turquette , Stephen Boyd Cc: Frank Oltmanns , "A . s . Dong" , Abel Vesa , Fabio Estevam , linux-arm-kernel@lists.infradead.org, linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, NXP Linux Team , Peng Fan , Pengutronix Kernel Team , Sascha Hauer , Shawn Guo Subject: [PATCH v2 1/2] clk: fractional-divider: Improve approximation when zero based Date: Tue, 13 Jun 2023 10:36:25 +0200 Message-ID: <20230613083626.227476-2-frank@oltmanns.dev> In-Reply-To: <20230613083626.227476-1-frank@oltmanns.dev> References: <20230613083626.227476-1-frank@oltmanns.dev> MIME-Version: 1.0 X-Rspamd-Queue-Id: 4QgMNX092sz9sTt Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org Consider the CLK_FRAC_DIVIDER_ZERO_BASED flag when finding the best approximation for m and n. By doing so, increase the range of valid values for the numerator and denominator by 1. Cc: A.s. Dong Signed-off-by: Frank Oltmanns --- drivers/clk/clk-fractional-divider.c | 26 +++++++++++++++++++------- 1 file changed, 19 insertions(+), 7 deletions(-) diff --git a/drivers/clk/clk-fractional-divider.c b/drivers/clk/clk-fractional-divider.c index 479297763e70..7da21cd2bdb1 100644 --- a/drivers/clk/clk-fractional-divider.c +++ b/drivers/clk/clk-fractional-divider.c @@ -123,6 +123,7 @@ void clk_fractional_divider_general_approximation(struct clk_hw *hw, unsigned long *m, unsigned long *n) { struct clk_fractional_divider *fd = to_clk_fd(hw); + unsigned long max_m, max_n; /* * Get rate closer to *parent_rate to guarantee there is no overflow @@ -138,9 +139,15 @@ void clk_fractional_divider_general_approximation(struct clk_hw *hw, rate <<= scale - fd->nwidth; } - rational_best_approximation(rate, *parent_rate, - GENMASK(fd->mwidth - 1, 0), GENMASK(fd->nwidth - 1, 0), - m, n); + if (fd->flags & CLK_FRAC_DIVIDER_ZERO_BASED) { + max_m = 1 << fd->mwidth; + max_n = 1 << fd->nwidth; + } else { + max_m = GENMASK(fd->mwidth - 1, 0); + max_n = GENMASK(fd->nwidth - 1, 0); + } + + rational_best_approximation(rate, *parent_rate, max_m, max_n, m, n); } static long clk_fd_round_rate(struct clk_hw *hw, unsigned long rate, @@ -169,13 +176,18 @@ static int clk_fd_set_rate(struct clk_hw *hw, unsigned long rate, { struct clk_fractional_divider *fd = to_clk_fd(hw); unsigned long flags = 0; - unsigned long m, n; + unsigned long m, n, max_m, max_n; u32 mmask, nmask; u32 val; - rational_best_approximation(rate, parent_rate, - GENMASK(fd->mwidth - 1, 0), GENMASK(fd->nwidth - 1, 0), - &m, &n); + if (fd->flags & CLK_FRAC_DIVIDER_ZERO_BASED) { + max_m = 1 << fd->mwidth; + max_n = 1 << fd->nwidth; + } else { + max_m = GENMASK(fd->mwidth - 1, 0); + max_n = GENMASK(fd->nwidth - 1, 0); + } + rational_best_approximation(rate, parent_rate, max_m, max_n, &m, &n); if (fd->flags & CLK_FRAC_DIVIDER_ZERO_BASED) { m--; From patchwork Tue Jun 13 08:36:26 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Frank Oltmanns X-Patchwork-Id: 13278159 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 85D6AC77B7A for ; Tue, 13 Jun 2023 08:37:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241421AbjFMIg7 (ORCPT ); Tue, 13 Jun 2023 04:36:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45632 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241361AbjFMIgz (ORCPT ); Tue, 13 Jun 2023 04:36:55 -0400 Received: from mout-p-201.mailbox.org (mout-p-201.mailbox.org [80.241.56.171]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EEDADC9; Tue, 13 Jun 2023 01:36:50 -0700 (PDT) Received: from smtp2.mailbox.org (smtp2.mailbox.org [IPv6:2001:67c:2050:b231:465::2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-384) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mout-p-201.mailbox.org (Postfix) with ESMTPS id 4QgMNb3HFqz9shR; Tue, 13 Jun 2023 10:36:47 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oltmanns.dev; s=MBO0001; t=1686645407; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=2QT7MHfX8peA53ynMuB00iPI+BywwoKuEeVqMP/6k18=; b=P/QlygKgPabiC1k8Ql146kcuEAI6vyf9dnWDTo8OOuqmnGpru9E/LDcWrZ3IL4S6lJtGfS HXfp7avs4Ms5vJr1GWkBcBnK60rHHyql9d275CUeqzax9o8ORm208m71uSrqvyLAT9RcwF o4NF0nzECsC+wubY2p715E07h6EMj+MZ68JwXvT2ByiHBAbr08pS/GggjRUHkuyuOx74bu WtGBxzAEo3ONvT/64AnPspUoq9hdYFtgNZ1tDbecbV5fQ51vCgWI/nhQn5pPw+KZsW3MvC mw+pyFQCTh+V2x2i0owk6GBpNzQh3rMyWTkDmioJxs5HhQxu2Cts49a9Gjsu1A== From: Frank Oltmanns To: Michael Turquette , Stephen Boyd Cc: Frank Oltmanns , "A.s. Dong" , Abel Vesa , Fabio Estevam , linux-arm-kernel@lists.infradead.org, linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, NXP Linux Team , Peng Fan , Pengutronix Kernel Team , Sascha Hauer , Shawn Guo Subject: [PATCH v2 2/2] clk: tests: Add tests for fractional divisor approximation Date: Tue, 13 Jun 2023 10:36:26 +0200 Message-ID: <20230613083626.227476-3-frank@oltmanns.dev> In-Reply-To: <20230613083626.227476-1-frank@oltmanns.dev> References: <20230613083626.227476-1-frank@oltmanns.dev> MIME-Version: 1.0 X-Rspamd-Queue-Id: 4QgMNb3HFqz9shR Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org In light of the recent discovery that the fractional divisor approximation does not utilize the full available range for clocks that are flagged CLK_FRAC_DIVIDER_ZERO_BASED, implement tests for the edge cases of this clock type. Signed-off-by: Frank Oltmanns Link: https://lore.kernel.org/lkml/20230529133433.56215-1-frank@oltmanns.dev --- drivers/clk/clk_test.c | 69 +++++++++++++++++++++++++++++++++++++++++- 1 file changed, 68 insertions(+), 1 deletion(-) diff --git a/drivers/clk/clk_test.c b/drivers/clk/clk_test.c index f9a5c2964c65..b247ba841cbd 100644 --- a/drivers/clk/clk_test.c +++ b/drivers/clk/clk_test.c @@ -8,6 +8,9 @@ /* Needed for clk_hw_get_clk() */ #include "clk.h" +/* Needed for clk_fractional_divider_general_approximation */ +#include "clk-fractional-divider.h" + #include #define DUMMY_CLOCK_INIT_RATE (42 * 1000 * 1000) @@ -2394,6 +2397,69 @@ static struct kunit_suite clk_mux_notifier_test_suite = { .test_cases = clk_mux_notifier_test_cases, }; + +/* + * Test that clk_fractional_divider_general_approximation will work with the + * highest available numerator and denominator. + */ +static void clk_fd_test_round_rate_max_mn(struct kunit *test) +{ + struct clk_fractional_divider *fd; + struct clk_hw *hw; + unsigned long rate, parent_rate, m, n; + + fd = kunit_kzalloc(test, sizeof(*fd), GFP_KERNEL); + KUNIT_ASSERT_NOT_NULL(test, fd); + + fd->mwidth = 3; + fd->nwidth = 3; + + hw = &fd->hw; + + rate = DUMMY_CLOCK_RATE_1; + + // Highest denominator, no flags + parent_rate = 10 * DUMMY_CLOCK_RATE_1; + clk_fractional_divider_general_approximation(hw, rate, &parent_rate, &m, &n); + KUNIT_EXPECT_EQ(test, m, 1); + KUNIT_EXPECT_EQ(test, n, 7); + + // Highest numerator, no flags + parent_rate = DUMMY_CLOCK_RATE_1 / 10; + clk_fractional_divider_general_approximation(hw, rate, &parent_rate, &m, &n); + KUNIT_EXPECT_EQ(test, m, 7); + KUNIT_EXPECT_EQ(test, n, 1); + + // Highest denominator, zero based + parent_rate = 10 * DUMMY_CLOCK_RATE_1; + fd->flags = CLK_FRAC_DIVIDER_ZERO_BASED; + clk_fractional_divider_general_approximation(hw, rate, &parent_rate, &m, &n); + KUNIT_EXPECT_EQ(test, m, 1); + KUNIT_EXPECT_EQ(test, n, 8); + + // Highest numerator, zero based + parent_rate = DUMMY_CLOCK_RATE_1 / 10; + clk_fractional_divider_general_approximation(hw, rate, &parent_rate, &m, &n); + KUNIT_EXPECT_EQ(test, m, 8); + KUNIT_EXPECT_EQ(test, n, 1); +} + +static struct kunit_case clk_fd_test_cases[] = { + KUNIT_CASE(clk_fd_test_round_rate_max_mn), + {} +}; + +/* + * Test suite for a fractional divider clock. + * + * These tests exercise the fractional divider API: clk_recalc_rate, + * clk_set_rate(), clk_round_rate(). + */ +static struct kunit_suite clk_fd_test_suite = { + .name = "clk-fd-test", + .test_cases = clk_fd_test_cases, +}; + kunit_test_suites( &clk_leaf_mux_set_rate_parent_test_suite, &clk_test_suite, @@ -2406,6 +2472,7 @@ kunit_test_suites( &clk_range_maximize_test_suite, &clk_range_minimize_test_suite, &clk_single_parent_mux_test_suite, - &clk_uncached_test_suite + &clk_uncached_test_suite, + &clk_fd_test_suite ); MODULE_LICENSE("GPL v2");