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Message-Id: <20220302145733.12606-5-pali@kernel.org> Date: Wed, 2 Mar 2022 15:57:33 +0100 From: Pali Rohár <pali@...nel.org> To: Lorenzo Pieralisi <lorenzo.pieralisi@....com>, Bjorn Helgaas <bhelgaas@...gle.com>, Rob Herring <robh+dt@...nel.org>, Andrew Lunn <andrew@...n.ch>, Thomas Petazzoni <thomas.petazzoni@...tlin.com>, Krzysztof Wilczyński <kw@...ux.com>, Marek Behún <kabel@...nel.org>, Russell King <rmk+kernel@...linux.org.uk> Cc: linux-pci@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org Subject: [PATCH v2 4/4] PCI: mvebu: Add support for sending Set_Slot_Power_Limit message If DT supplies the 'slot-power-limit-milliwatt' property, program the value in the Slot Power Limit in the Slot Capabilities register and program the Root Port to send a Set_Slot_Power_Limit Message when the Link transitions to DL_Up. Signed-off-by: Pali Rohár <pali@...nel.org> --- Changes in v2: * Fix handling of slot power limit with scale x1.0 (0x00 value) * Use FIELD_PREP instead of _SHIFT macros * Changed commit message to Bjorn's suggestion * Changed comments in the code to match PCIe spec * Preserve user settings of PCI_EXP_SLTCTL_ASPL_DISABLE bit --- drivers/pci/controller/pci-mvebu.c | 96 ++++++++++++++++++++++++++++-- 1 file changed, 91 insertions(+), 5 deletions(-) diff --git a/drivers/pci/controller/pci-mvebu.c b/drivers/pci/controller/pci-mvebu.c index a75d2b9196f9..26ae7c29fece 100644 --- a/drivers/pci/controller/pci-mvebu.c +++ b/drivers/pci/controller/pci-mvebu.c @@ -8,6 +8,7 @@ #include <linux/kernel.h> #include <linux/module.h> #include <linux/pci.h> +#include <linux/bitfield.h> #include <linux/clk.h> #include <linux/delay.h> #include <linux/gpio.h> @@ -66,6 +67,12 @@ #define PCIE_STAT_BUS 0xff00 #define PCIE_STAT_DEV 0x1f0000 #define PCIE_STAT_LINK_DOWN BIT(0) +#define PCIE_SSPL_OFF 0x1a0c +#define PCIE_SSPL_VALUE_SHIFT 0 +#define PCIE_SSPL_VALUE_MASK GENMASK(7, 0) +#define PCIE_SSPL_SCALE_SHIFT 8 +#define PCIE_SSPL_SCALE_MASK GENMASK(9, 8) +#define PCIE_SSPL_ENABLE BIT(16) #define PCIE_RC_RTSTA 0x1a14 #define PCIE_DEBUG_CTRL 0x1a60 #define PCIE_DEBUG_SOFT_RESET BIT(20) @@ -111,6 +118,8 @@ struct mvebu_pcie_port { struct mvebu_pcie_window iowin; u32 saved_pcie_stat; struct resource regs; + u8 slot_power_limit_value; + u8 slot_power_limit_scale; struct irq_domain *intx_irq_domain; raw_spinlock_t irq_lock; int intx_irq; @@ -239,7 +248,7 @@ static void mvebu_pcie_setup_wins(struct mvebu_pcie_port *port) static void mvebu_pcie_setup_hw(struct mvebu_pcie_port *port) { - u32 ctrl, lnkcap, cmd, dev_rev, unmask; + u32 ctrl, lnkcap, cmd, dev_rev, unmask, sspl; /* Setup PCIe controller to Root Complex mode. */ ctrl = mvebu_readl(port, PCIE_CTRL_OFF); @@ -292,6 +301,20 @@ static void mvebu_pcie_setup_hw(struct mvebu_pcie_port *port) /* Point PCIe unit MBUS decode windows to DRAM space. */ mvebu_pcie_setup_wins(port); + /* + * Program Root Port to automatically send Set_Slot_Power_Limit + * PCIe Message when changing status from Dl_Down to Dl_Up and valid + * slot power limit was specified. + */ + sspl = mvebu_readl(port, PCIE_SSPL_OFF); + sspl &= ~(PCIE_SSPL_VALUE_MASK | PCIE_SSPL_SCALE_MASK | PCIE_SSPL_ENABLE); + if (port->slot_power_limit_value) { + sspl |= port->slot_power_limit_value << PCIE_SSPL_VALUE_SHIFT; + sspl |= port->slot_power_limit_scale << PCIE_SSPL_SCALE_SHIFT; + sspl |= PCIE_SSPL_ENABLE; + } + mvebu_writel(port, sspl, PCIE_SSPL_OFF); + /* Mask all interrupt sources. */ mvebu_writel(port, ~PCIE_INT_ALL_MASK, PCIE_INT_UNMASK_OFF); @@ -628,9 +651,23 @@ mvebu_pci_bridge_emul_pcie_conf_read(struct pci_bridge_emul *bridge, (PCI_EXP_LNKSTA_DLLLA << 16) : 0); break; - case PCI_EXP_SLTCTL: - *value = PCI_EXP_SLTSTA_PDS << 16; + case PCI_EXP_SLTCTL: { + u16 slotsta = le16_to_cpu(bridge->pcie_conf.slotsta); + u32 val = 0; + /* + * When slot power limit was not specified in DT then + * ASPL_DISABLE bit is stored only in emulated config space. + * Otherwise reflect status of PCIE_SSPL_ENABLE bit in HW. + */ + if (!port->slot_power_limit_value) + val |= slotctl & PCI_EXP_SLTCTL_ASPL_DISABLE; + else if (!(mvebu_readl(port, PCIE_SSPL_OFF) & PCIE_SSPL_ENABLE)) + val |= PCI_EXP_SLTCTL_ASPL_DISABLE; + /* This callback is 32-bit and in high bits is slot status. */ + val |= slotsta << 16; + *value = val; break; + } case PCI_EXP_RTSTA: *value = mvebu_readl(port, PCIE_RC_RTSTA); @@ -774,6 +811,22 @@ mvebu_pci_bridge_emul_pcie_conf_write(struct pci_bridge_emul *bridge, mvebu_writel(port, new, PCIE_CAP_PCIEXP + PCI_EXP_LNKCTL); break; + case PCI_EXP_SLTCTL: + /* + * Allow to change PCIE_SSPL_ENABLE bit only when slot power + * limit was specified in DT and configured into HW. + */ + if ((mask & PCI_EXP_SLTCTL_ASPL_DISABLE) && + port->slot_power_limit_value) { + u32 sspl = mvebu_readl(port, PCIE_SSPL_OFF); + if (new & PCI_EXP_SLTCTL_ASPL_DISABLE) + sspl &= ~PCIE_SSPL_ENABLE; + else + sspl |= PCIE_SSPL_ENABLE; + mvebu_writel(port, sspl, PCIE_SSPL_OFF); + } + break; + case PCI_EXP_RTSTA: /* * PME Status bit in Root Status Register (PCIE_RC_RTSTA) @@ -868,8 +921,26 @@ static int mvebu_pci_bridge_emul_init(struct mvebu_pcie_port *port) /* * Older mvebu hardware provides PCIe Capability structure only in * version 1. New hardware provides it in version 2. + * Enable slot support which is emulated. */ - bridge->pcie_conf.cap = cpu_to_le16(pcie_cap_ver); + bridge->pcie_conf.cap = cpu_to_le16(pcie_cap_ver | PCI_EXP_FLAGS_SLOT); + + /* + * Set Presence Detect State bit permanently as there is no support for + * unplugging PCIe card from the slot. Assume that PCIe card is always + * connected in slot. + * + * Set physical slot number to port+1 as mvebu ports are indexed from + * zero and zero value is reserved for ports within the same silicon + * as Root Port which is not mvebu case. + * + * Also set correct slot power limit. + */ + bridge->pcie_conf.slotcap = cpu_to_le32( + FIELD_PREP(PCI_EXP_SLTCAP_SPLV, port->slot_power_limit_value) | + FIELD_PREP(PCI_EXP_SLTCAP_SPLS, port->slot_power_limit_scale) | + FIELD_PREP(PCI_EXP_SLTCAP_PSN, port->port+1)); + bridge->pcie_conf.slotsta = cpu_to_le16(PCI_EXP_SLTSTA_PDS); bridge->subsystem_vendor_id = ssdev_id & 0xffff; bridge->subsystem_id = ssdev_id >> 16; @@ -1191,6 +1262,7 @@ static int mvebu_pcie_parse_port(struct mvebu_pcie *pcie, { struct device *dev = &pcie->pdev->dev; enum of_gpio_flags flags; + u32 slot_power_limit; int reset_gpio, ret; u32 num_lanes; @@ -1291,6 +1363,15 @@ static int mvebu_pcie_parse_port(struct mvebu_pcie *pcie, port->reset_gpio = gpio_to_desc(reset_gpio); } + slot_power_limit = of_pci_get_slot_power_limit(child, + &port->slot_power_limit_value, + &port->slot_power_limit_scale); + if (slot_power_limit) + dev_info(dev, "%s: Slot power limit %u.%uW\n", + port->name, + slot_power_limit / 1000, + (slot_power_limit / 100) % 10); + port->clk = of_clk_get_by_name(child, NULL); if (IS_ERR(port->clk)) { dev_err(dev, "%s: cannot get clock\n", port->name); @@ -1587,7 +1668,7 @@ static int mvebu_pcie_remove(struct platform_device *pdev) { struct mvebu_pcie *pcie = platform_get_drvdata(pdev); struct pci_host_bridge *bridge = pci_host_bridge_from_priv(pcie); - u32 cmd; + u32 cmd, sspl; int i; /* Remove PCI bus with all devices. */ @@ -1624,6 +1705,11 @@ static int mvebu_pcie_remove(struct platform_device *pdev) /* Free config space for emulated root bridge. */ pci_bridge_emul_cleanup(&port->bridge); + /* Disable sending Set_Slot_Power_Limit PCIe Message. */ + sspl = mvebu_readl(port, PCIE_SSPL_OFF); + sspl &= ~(PCIE_SSPL_VALUE_MASK | PCIE_SSPL_SCALE_MASK | PCIE_SSPL_ENABLE); + mvebu_writel(port, sspl, PCIE_SSPL_OFF); + /* Disable and clear BARs and windows. */ mvebu_pcie_disable_wins(port); -- 2.20.1
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