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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F01A0C433F5 for ; Wed, 13 Apr 2022 20:24:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236225AbiDMU1D (ORCPT ); Wed, 13 Apr 2022 16:27:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60802 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233120AbiDMU1C (ORCPT ); Wed, 13 Apr 2022 16:27:02 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 702203BF95; Wed, 13 Apr 2022 13:24:37 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 05DB8B826A7; Wed, 13 Apr 2022 20:24:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 74DC9C385A3; Wed, 13 Apr 2022 20:24:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1649881474; bh=2RUFHWOD1DBlUTn0rn61mqQySRcJDmALxwyHtmWQLn4=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=aPH+4hetSldTnCtYHjSjHZlS36hTdhia7zn2zq5SX+9G3sxebtuIGhxzH4OX+gewX PwKr+qSWt43HeN9yS2K6MnnPAPG8eQ8M7OHsb0I5BTWocd687ok+ILwuCKlqU/9+HS 2jifTC9ITN1nypIBnd1AnFFy6wzKK6342rYpa8cEAusITN6nQFyFfbQJAhrikjtyLz /+ghhMdq4TNhVltD1YGkZ6B79kRNI6KvcS7IVuRLq8QAagLI0/fjR7YjpmNlp5GxuD j/XV3OtY6eRyeRVPZRo5ShiVXbh48oY1pTyGusvti9IMmzdPJW+wjHfKwWzdtnuDAg lRhsVVhxYZ2XQ== Date: Wed, 13 Apr 2022 15:24:33 -0500 From: Bjorn Helgaas To: Pali =?iso-8859-1?Q?Roh=E1r?= Cc: Lorenzo Pieralisi , Bjorn Helgaas , Rob Herring , Andrew Lunn , Thomas Petazzoni , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , Marek =?iso-8859-1?Q?Beh=FAn?= , Russell King , linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 3/4] PCI: Add function for parsing 'slot-power-limit-milliwatt' DT property Message-ID: <20220413202433.GA688099@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220412094946.27069-4-pali@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Tue, Apr 12, 2022 at 11:49:45AM +0200, Pali Rohár wrote: > Add function of_pci_get_slot_power_limit(), which parses the > 'slot-power-limit-milliwatt' DT property, returning the value in > milliwatts and in format ready for the PCIe Slot Capabilities Register. > > Signed-off-by: Pali Rohár > Signed-off-by: Marek Behún > Reviewed-by: Rob Herring Looks good to me! Thank you! Reviewed-by: Bjorn Helgaas > --- > Changes in v4: > * Set 239 W when DT slot-power-limit-milliwatt is between 239 W and 250 W > * Fix returning power limit value > Changes in v3: > * Set 600 W when DT slot-power-limit-milliwatt > 600 W > Changes in v2: > * Added support for PCIe 6.0 slot power limit encodings > * Round down slot power limit value > --- > drivers/pci/of.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++ > drivers/pci/pci.h | 15 ++++++++++ > 2 files changed, 85 insertions(+) > > diff --git a/drivers/pci/of.c b/drivers/pci/of.c > index cb2e8351c2cc..6c1b81304665 100644 > --- a/drivers/pci/of.c > +++ b/drivers/pci/of.c > @@ -633,3 +633,73 @@ int of_pci_get_max_link_speed(struct device_node *node) > return max_link_speed; > } > EXPORT_SYMBOL_GPL(of_pci_get_max_link_speed); > + > +/** > + * of_pci_get_slot_power_limit - Parses the "slot-power-limit-milliwatt" > + * property. > + * > + * @node: device tree node with the slot power limit information > + * @slot_power_limit_value: pointer where the value should be stored in PCIe > + * Slot Capabilities Register format > + * @slot_power_limit_scale: pointer where the scale should be stored in PCIe > + * Slot Capabilities Register format > + * > + * Returns the slot power limit in milliwatts and if @slot_power_limit_value > + * and @slot_power_limit_scale pointers are non-NULL, fills in the value and > + * scale in format used by PCIe Slot Capabilities Register. > + * > + * If the property is not found or is invalid, returns 0. > + */ > +u32 of_pci_get_slot_power_limit(struct device_node *node, > + u8 *slot_power_limit_value, > + u8 *slot_power_limit_scale) > +{ > + u32 slot_power_limit_mw; > + u8 value, scale; > + > + if (of_property_read_u32(node, "slot-power-limit-milliwatt", > + &slot_power_limit_mw)) > + slot_power_limit_mw = 0; > + > + /* Calculate Slot Power Limit Value and Slot Power Limit Scale */ > + if (slot_power_limit_mw == 0) { > + value = 0x00; > + scale = 0; > + } else if (slot_power_limit_mw <= 255) { > + value = slot_power_limit_mw; > + scale = 3; > + } else if (slot_power_limit_mw <= 255*10) { > + value = slot_power_limit_mw / 10; > + scale = 2; > + slot_power_limit_mw = slot_power_limit_mw / 10 * 10; > + } else if (slot_power_limit_mw <= 255*100) { > + value = slot_power_limit_mw / 100; > + scale = 1; > + slot_power_limit_mw = slot_power_limit_mw / 100 * 100; > + } else if (slot_power_limit_mw <= 239*1000) { > + value = slot_power_limit_mw / 1000; > + scale = 0; > + slot_power_limit_mw = slot_power_limit_mw / 1000 * 1000; > + } else if (slot_power_limit_mw < 250*1000) { > + value = 0xEF; > + scale = 0; > + slot_power_limit_mw = 239*1000; > + } else if (slot_power_limit_mw <= 600*1000) { > + value = 0xF0 + (slot_power_limit_mw / 1000 - 250) / 25; > + scale = 0; > + slot_power_limit_mw = slot_power_limit_mw / (1000*25) * (1000*25); > + } else { > + value = 0xFE; > + scale = 0; > + slot_power_limit_mw = 600*1000; > + } > + > + if (slot_power_limit_value) > + *slot_power_limit_value = value; > + > + if (slot_power_limit_scale) > + *slot_power_limit_scale = scale; > + > + return slot_power_limit_mw; > +} > +EXPORT_SYMBOL_GPL(of_pci_get_slot_power_limit); > diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h > index 3d60cabde1a1..e10cdec6c56e 100644 > --- a/drivers/pci/pci.h > +++ b/drivers/pci/pci.h > @@ -627,6 +627,9 @@ struct device_node; > int of_pci_parse_bus_range(struct device_node *node, struct resource *res); > int of_get_pci_domain_nr(struct device_node *node); > int of_pci_get_max_link_speed(struct device_node *node); > +u32 of_pci_get_slot_power_limit(struct device_node *node, > + u8 *slot_power_limit_value, > + u8 *slot_power_limit_scale); > void pci_set_of_node(struct pci_dev *dev); > void pci_release_of_node(struct pci_dev *dev); > void pci_set_bus_of_node(struct pci_bus *bus); > @@ -653,6 +656,18 @@ of_pci_get_max_link_speed(struct device_node *node) > return -EINVAL; > } > > +static inline u32 > +of_pci_get_slot_power_limit(struct device_node *node, > + u8 *slot_power_limit_value, > + u8 *slot_power_limit_scale) > +{ > + if (slot_power_limit_value) > + *slot_power_limit_value = 0; > + if (slot_power_limit_scale) > + *slot_power_limit_scale = 0; > + return 0; > +} > + > static inline void pci_set_of_node(struct pci_dev *dev) { } > static inline void pci_release_of_node(struct pci_dev *dev) { } > static inline void pci_set_bus_of_node(struct pci_bus *bus) { } > -- > 2.20.1 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel