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Merge branch 'remotes/lorenzo/pci/power-slot'
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- Add of_pci_get_slot_power_limit() to parse the
  'slot-power-limit-milliwatt' DT property (Pali Rohár)

- Add mvebu support for sending Set_Slot_Power_Limit message (Pali Rohár)

* remotes/lorenzo/pci/power-slot:
  PCI: mvebu: Add support for sending Set_Slot_Power_Limit message
  PCI: Add function for parsing 'slot-power-limit-milliwatt' DT property
  PCI: Add PCI_EXP_SLTCTL_ASPL_DISABLE macro
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Bjorn Helgaas committed May 24, 2022
2 parents 5ae34e8 + 0d5b8c2 commit b0266c4
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Showing 4 changed files with 178 additions and 5 deletions.
97 changes: 92 additions & 5 deletions drivers/pci/controller/pci-mvebu.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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>
Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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);

Expand Down Expand Up @@ -628,9 +651,24 @@ 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 slotctl = le16_to_cpu(bridge->pcie_conf.slotctl);
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);
Expand Down Expand Up @@ -774,6 +812,22 @@ 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)
Expand Down Expand Up @@ -868,8 +922,26 @@ 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;
Expand Down Expand Up @@ -1191,6 +1263,7 @@ 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;

Expand Down Expand Up @@ -1291,6 +1364,15 @@ 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);
Expand Down Expand Up @@ -1588,7 +1670,7 @@ 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. */
Expand Down Expand Up @@ -1625,6 +1707,11 @@ 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);

Expand Down
70 changes: 70 additions & 0 deletions drivers/pci/of.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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);
15 changes: 15 additions & 0 deletions drivers/pci/pci.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand All @@ -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) { }
Expand Down
1 change: 1 addition & 0 deletions include/uapi/linux/pci_regs.h
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Original file line number Diff line number Diff line change
Expand Up @@ -616,6 +616,7 @@
#define PCI_EXP_SLTCTL_PWR_OFF 0x0400 /* Power Off */
#define PCI_EXP_SLTCTL_EIC 0x0800 /* Electromechanical Interlock Control */
#define PCI_EXP_SLTCTL_DLLSCE 0x1000 /* Data Link Layer State Changed Enable */
#define PCI_EXP_SLTCTL_ASPL_DISABLE 0x2000 /* Auto Slot Power Limit Disable */
#define PCI_EXP_SLTCTL_IBPD_DISABLE 0x4000 /* In-band PD disable */
#define PCI_EXP_SLTSTA 0x1a /* Slot Status */
#define PCI_EXP_SLTSTA_ABP 0x0001 /* Attention Button Pressed */
Expand Down

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