From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout-p-103.mailbox.org (mout-p-103.mailbox.org [80.241.56.161]) (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 D4C1D1DA57; Tue, 29 Sep 2026 00:42:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=80.241.56.161 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790642565; cv=none; b=CcFkzd1iX6rNSIoFDwBk1bIU2uVB2/sYCZERmq/7VyTQGQqw0JkCznJoJKzfdmpVEwS8TpMPNy/sRd85zQRPcBLy4mRYHQ0PGAjsT3DA8HQzZGaSJvFKoWrFhjm3cVry1WWGTu3lvyUAcm8dF8Ez0jDLwgPo2B35Xn0cp7nVAPk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790642565; c=relaxed/simple; bh=OWhcwknLRyPzDmXgalH6NabLxd+2MPu1XxuBbMgZxsY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=QH0/YG0ITOIGnuZYFO/7UtZgD5wr8MZgGGrTOUJfoK6oaHy2XH8eNP63C6J5Z0kgEM1eGDSzojDmcM1QIwTG7TQER99J+z1yiA3tarW6D88xPCGz9yQ3ZFe2vwaUKC8UJrdfLCtci8xIQGNcg/9zChHmEiQHa8IPxXOXV+zjWr8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=mailbox.org; spf=pass smtp.mailfrom=mailbox.org; dkim=pass (2048-bit key) header.d=mailbox.org header.i=@mailbox.org header.b=ysoZstVY; arc=none smtp.client-ip=80.241.56.161 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=mailbox.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mailbox.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=mailbox.org header.i=@mailbox.org header.b="ysoZstVY" Received: from smtp2.mailbox.org (smtp2.mailbox.org [10.196.197.2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mout-p-103.mailbox.org (Postfix) with ESMTPS id 4htzsj020ZzKn2J; Tue, 29 Sep 2026 02:42:33 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mailbox.org; s=mail20150812; t=1790642553; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=qYZdjHSXMYQifjl/oycijS7tIo3obhxZW530Z+Tdr74=; b=ysoZstVYT9kJZ0p+C3oJMwuX/R3prdjcwqklLJ814vDuPxUJYwk4I4JlifmfqZK1II4bCG GPQ0F2CaCZrjdgdqAuBJbOI699d2+3nkumTLGq3T9nedDKQ9jnGcqX3trKwK0S0z/sCXCc Oc8Wcq1yoNLWXlhz8XzumjosPwTfw3jvCDnJ5Spa4qHHuICNvkyQ1ckUa8ep2efdqqsZO+ y46vKlbRu5FePJ0R7oYr64FkyltPdSuwpKgwqouS+Pe4ABfCWLZOREm+fZcb1ATaAxjTB+ F4qZiFhtd+K0Anf4Mc7ubjkP7slLdSydqPsae0IyQiWliQm0CoVhEM7VvS4JOg== Message-ID: Date: Tue, 29 Sep 2026 02:42:29 +0200 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 6/6] PCI: dwc: rcar-gen4: Add support for R-Car X5H PCIe4 To: Bjorn Helgaas Cc: linux-pci@vger.kernel.org, =?UTF-8?Q?Krzysztof_Wilczy=C5=84ski?= , Bjorn Helgaas , Conor Dooley , Geert Uytterhoeven , Krzysztof Kozlowski , Lorenzo Pieralisi , Manivannan Sadhasivam , Rob Herring , Yoshihiro Shimoda , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-renesas-soc@vger.kernel.org References: <20260928222442.GA2266778@bhelgaas> Content-Language: en-US From: Marek Vasut In-Reply-To: <20260928222442.GA2266778@bhelgaas> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-MBO-RS-META: n5r3abih9upesd63k85pf9uic4hcaarb X-MBO-RS-ID: 56a18349aca01d73551 On 9/29/26 12:24 AM, Bjorn Helgaas wrote: Hello Bjorn, >>> The gen5/pcie4 usage is confusing. >>> >>> I often push back on things like "PCIe Gen4" because it's ambiguous >>> (does it mean "compliant with base spec r4.0" or "supports 16 GT/s" or >>> something else), but it's so widely used to mean transfer rate that >>> it's hard to resist, and the best I can hope for is clarification. >>> >>> But in "renesas,rcar-gen5-pcie4", I don't know what the 5 and the 4 >>> mean. Maybe "gen5" refers to some internal R-Car thing, and "pcie4" >>> is something like "PCIe Gen4, i.e., 16 GT/s"? >> >> Gen5 refers to R-Car Gen5 (5th R-Car SoC generation). >> >> PCIe4 refers to the PCIe Gen4 core in the R-Car Gen5 SoC. There is also PCIe >> Gen6 core in the same SoC, but that will require a different driver and >> different compatible string. >> >> Since none of this shipped in any kernel version yet, would you prefer some >> sort of rename ? I can send patches. > > Huh. TIL that pcie-rcar-gen4.c refers to the 4th generation R-Car > SoCs Yes. > (and, I guess the point of this series is to add support for 5th > generation SoCs), not to PCIe Gen4 link speeds. Correct. > I see that > "renesas,rcar-genX" is all over the place in 'compatible' strings, so > I guess we should follow that precedent. Yes. > If the "renesas,rcar-gen5" SoC includes both PCIe Gen4 and PCIe Gen6 > cores, I suppose everybody refers to them as pcie-gen4 and pcie-gen6, > so the "renesas,rcar-gen5-pcie4" you used is probably the obvious > choice. Right, and also the least cumbersome compatible string I could come up with. > But maybe we can make commit logs less confusing by saying things > like: > > - R-Car Gen4 SoCs S4/V4H/V4M > - R-Car Gen5 SoC X5H > - the R-Car Gen5 SoC PCIe Gen4 core > - the R-Car R8A78000 X5H PCIe Gen4 core, which supports a x8 link at > 16 GT/s Understood, I'll expand future patches to be more explicit about this. Does that work for you ? -- Best regards, Marek Vasut