From patchwork Sun Oct 31 15:07:06 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Marek_Beh=C3=BAn?= X-Patchwork-Id: 12595175 X-Patchwork-Delegate: robh@kernel.org 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 839A3C4332F for ; Sun, 31 Oct 2021 15:07:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6183260EBB for ; Sun, 31 Oct 2021 15:07:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229838AbhJaPJq (ORCPT ); Sun, 31 Oct 2021 11:09:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:53472 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229745AbhJaPJn (ORCPT ); Sun, 31 Oct 2021 11:09:43 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 81FA260F46; Sun, 31 Oct 2021 15:07:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1635692831; bh=pu+nuuiYf3vFkm8I+mielJIumq1y5NXzzcjEOc9xynM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mcHN4YvC0zWHvNsPeMq1plBp4V937Qq4e8uD3KmwQtRY8DrP6wl9D2PdmYrvp0CO3 OkLbCc6VN7guQXNlUsV7jZmoJDQeRcHXZpMk1HrKeCoJF1jpd0p1Vkt7eUhB+ivfDs hYzwSmpAONK0LclUyjPcORusPyg3nt2qWBbzJEiWopCyBClpP3iIHNvcu0nUQ97ais arfpQSQoH5qgYVcH1ZJg3+0iDJ/2vE958Ca+rXktCT1TZPSOC5EwRFlLa6mpTibI04 P4yx1Wxfi5IOLPgqdySqd1ffJK8MQCbGjpZxDyRlTcKNjUHtY9zavOcUErZJDApphy V4GEtwyXaDSRg== From: =?utf-8?q?Marek_Beh=C3=BAn?= To: devicetree@vger.kernel.org, robh+dt@kernel.org, linux-pci@vger.kernel.org, Bjorn Helgaas Cc: =?utf-8?q?Pali_Roh=C3=A1r?= , =?utf-8?q?Marek_Beh=C3=BA?= =?utf-8?q?n?= Subject: [PATCH dt + pci 2/2] PCI: Add function for parsing `slot-power-limit-milliwatt` DT property Date: Sun, 31 Oct 2021 16:07:06 +0100 Message-Id: <20211031150706.27873-2-kabel@kernel.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20211031150706.27873-1-kabel@kernel.org> References: <20211031150706.27873-1-kabel@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org From: Pali Rohár 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 Acked-by: Bjorn Helgaas --- drivers/pci/of.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++ drivers/pci/pci.h | 15 +++++++++++ 2 files changed, 79 insertions(+) diff --git a/drivers/pci/of.c b/drivers/pci/of.c index d84381ce82b5..9c1a38d5dd99 100644 --- a/drivers/pci/of.c +++ b/drivers/pci/of.c @@ -627,3 +627,67 @@ 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; + u8 value, scale; + + if (of_property_read_u32(node, "slot-power-limit-milliwatt", + &slot_power_limit)) + slot_power_limit = 0; + + /* Calculate Slot Power Limit Value and Slot Power Limit Scale */ + if (slot_power_limit == 0) { + value = 0x00; + scale = 0; + } else if (slot_power_limit <= 255) { + value = slot_power_limit; + scale = 3; + } else if (slot_power_limit <= 255*10) { + value = slot_power_limit / 10; + scale = 2; + } else if (slot_power_limit <= 255*100) { + value = slot_power_limit / 100; + scale = 1; + } else if (slot_power_limit <= 239*1000) { + value = slot_power_limit / 1000; + scale = 0; + } else if (slot_power_limit <= 250*1000) { + value = 0xF0; + scale = 0; + } else if (slot_power_limit <= 275*1000) { + value = 0xF1; + scale = 0; + } else { + value = 0xF2; + scale = 0; + } + + if (slot_power_limit_value) + *slot_power_limit_value = value; + + if (slot_power_limit_scale) + *slot_power_limit_scale = scale; + + return slot_power_limit; +} +EXPORT_SYMBOL_GPL(of_pci_get_slot_power_limit); diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 1cce56c2aea0..9352278141be 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -665,6 +665,9 @@ 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); @@ -691,6 +694,18 @@ 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) { }