From 3514828cb2cf52e545fe71bb7dc2d105d8b0084e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Pali=20Roh=C3=A1r?= Date: Sun, 31 Oct 2021 16:07:06 +0100 Subject: [PATCH 48/90] PCI: Add function for parsing 'slot-power-limit-milliwatt' DT property MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 --- 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 d84381ce82b5..1372da653929 100644 --- a/drivers/pci/of.c +++ b/drivers/pci/of.c @@ -627,3 +627,73 @@ 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 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) { } -- 2.34.1