From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sender4-pp-o94.zoho.com (sender4-pp-o94.zoho.com [136.143.188.94]) (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 377AA3C1994; Thu, 19 Mar 2026 11:11:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.94 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773918715; cv=pass; b=r/fqQ0TfvAeO+T+VmBcgJx7E7WY2AiNTk59LDXxAT5azJelkWac+rFQ4bfPsYgbTXqaCOtBPA9aix7nMQdDdE/eIH2aYlko7ehUR4fE9wYwSX0nukPSeMrAWCp1H0iIiT1MMKlxff3XfayLeWZZ15oq7jEVDLgiuDFJIa1ew+tg= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773918715; c=relaxed/simple; bh=8enFaI0Xpshnx8NTdJPcbIB+7j0NmWlY+Ki0wwgJh9I=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=PIqK3My7G0k4y9LuIMAnjVVW48McvqiSmzjzqJZ3v9nFIj3VUnkzk7vk7VyLP+JgX/xEUl5NYjb2LYgjSOSputG6eND1fG4c2M+/H3I5dSlVKHtJyjZjgJpAK46DVDUz3aXhXP4G94KkL3K1/m4l663Izmm7aqFNiZvo2TOjc4E= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=zohomail.com; spf=pass smtp.mailfrom=zohomail.com; dkim=pass (1024-bit key) header.d=zohomail.com header.i=ming.li@zohomail.com header.b=Pf0Gbb7P; arc=pass smtp.client-ip=136.143.188.94 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=zohomail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zohomail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zohomail.com header.i=ming.li@zohomail.com header.b="Pf0Gbb7P" ARC-Seal: i=1; a=rsa-sha256; t=1773918702; cv=none; d=zohomail.com; s=zohoarc; b=G2KFIxbA9bgAWFjvw0k855eBSBDvUgzJW9LCX8AUxpKez+xOlU6v9GQMCWlOEbqHQ5nZbbbQIY8J15657OX0hYXM/x1mbhDJ2nlEQdVTbPQpB/8LBrKJ4Vr48LcHeBVyEFT+Bi6eChVytojfo58setMAJS6e2RDykU8oXXk9BEY= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1773918702; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=9xNbJd6eNoKvWQudMYAZu2EOUdzU/Q3F479XcjRaRKk=; b=jmxsLmS03+CuyGCLRcZ3DeZGoCIAp1dKdyymx18Gi8bFJqH2UEPpS8IaNhvPQlwSPx0/orvNWGLBLzKDRSUrqClqd704y5Ib3UWZnxSFV+bWCk1Ua0yn5blFlveaRSX1i+7DkzRMNSxljatC+eoQPnFb7JqstcphAFquIC6i3v0= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=zohomail.com; spf=pass smtp.mailfrom=ming.li@zohomail.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1773918702; s=zm2022; d=zohomail.com; i=ming.li@zohomail.com; h=Message-ID:Date:Date:MIME-Version:Subject:Subject:To:To:Cc:Cc:References:From:From:In-Reply-To:Content-Type:Content-Transfer-Encoding:Feedback-ID:Message-Id:Reply-To; bh=9xNbJd6eNoKvWQudMYAZu2EOUdzU/Q3F479XcjRaRKk=; b=Pf0Gbb7Pjtoeo10b3h1GjcWSjoMawwoY3Ph0HzDGL5148FoHjl66E17InwOL9a6P 6ITrXmrCfDl24DmvcRQcAATTXacWlVplj3HwS8Ybua9vGN4/CfoWYK+Q0m1DLXcHUJn 2tAQxxgae+XxTj/ke5pZHG4nDJUQwLcZrtOzvg8g= Received: by mx.zohomail.com with SMTPS id 1773918700594461.5822884998462; Thu, 19 Mar 2026 04:11:40 -0700 (PDT) Message-ID: <291ac46e-67cb-4732-8626-e0c434ede12f@zohomail.com> Date: Thu, 19 Mar 2026 19:11:34 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] cxl/hdm: Add support for 32 switch decoders To: Dave Jiang Cc: linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org, Davidlohr Bueso , Jonathan Cameron , Alison Schofield , Vishal Verma , Ira Weiny , Dan Williams References: <20260318-add_support_for_32_decoders-v1-1-bb7b41efde2a@zohomail.com> <69f68851-9e02-431a-9331-8f687bb2fa4a@intel.com> From: Li Ming In-Reply-To: <69f68851-9e02-431a-9331-8f687bb2fa4a@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Feedback-ID: rr0801122883dafd051bca49f3013723c8000059bba104775c262d16cf0fef00224de091d8f8633b187fd7b263:zu0801122768f1dde2545e5dcb3b582ad600000677fc07c3c5c6232081c3f3dc3bf5b37306e57db581188702:rf0801122d47ed7f609cf86ffd73ea2c0c00001e2688ca9f83917f05a44bb395d2d5201cc27669071415735ddc2242125ad5:ZohoMail X-ZohoMailClient: External 在 2026/3/18 23:40, Dave Jiang 写道: > > On 3/18/26 6:00 AM, Li Ming wrote: >> Per CXL r4.0 section 8.2.4.20.1. CXL host bridge and switch ports can >> support 32 HDM decoders. Current implementation misses some decoders on >> CXL host bridge and switch in the case that the value of Decoder Count >> field in CXL HDM decoder Capability Register is greater than or equal to >> 9. >> >> Update calculation implementation to ensure the decoder count calculation >> is correct for CXL host bridge/switch ports. >> >> Signed-off-by: Li Ming >> --- >> drivers/cxl/cxl.h | 7 ++++++- >> 1 file changed, 6 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h >> index 9b947286eb9b..466b8eeefed7 100644 >> --- a/drivers/cxl/cxl.h >> +++ b/drivers/cxl/cxl.h >> @@ -77,7 +77,12 @@ static inline int cxl_hdm_decoder_count(u32 cap_hdr) >> { >> int val = FIELD_GET(CXL_HDM_DECODER_COUNT_MASK, cap_hdr); >> >> - return val ? val * 2 : 1; >> + if (!val) >> + return 1; >> + else if (val <= 8) >> + return val * 2; >> + else >> + return 4 * (val - 4); > That looks a bit messy. How about: > > switch (val) { > case 0: > return 1; > case 1..8: > return val * 2; > case 9..12: > return val 4 * (val - 4); > default: > return -ENXIO; > } > > DJ Sure, will do that in v2. Ming