* [PATCH v4 3/4] PCI: Add function for parsing 'slot-power-limit-milliwatt' DT property
2022-04-11 18:58 [PATCH v4 0/4] PCI: mvebu: Slot support Pali Rohár
2022-04-11 18:58 ` [PATCH v4 1/4] PCI: Add PCI_EXP_SLTCTL_ASPL_DISABLE macro Pali Rohár
2022-04-11 18:58 ` [PATCH v4 2/4] dt-bindings: Add 'slot-power-limit-milliwatt' PCIe port property Pali Rohár
@ 2022-04-11 18:58 ` Pali Rohár
2022-04-11 18:58 ` [PATCH v4 4/4] PCI: mvebu: Add support for sending Set_Slot_Power_Limit message Pali Rohár
3 siblings, 0 replies; 5+ messages in thread
From: Pali Rohár @ 2022-04-11 18:58 UTC (permalink / raw)
To: Lorenzo Pieralisi, Bjorn Helgaas, Rob Herring, Andrew Lunn,
Thomas Petazzoni, Krzysztof Wilczyński, Marek Behún,
Russell King
Cc: linux-pci, linux-arm-kernel, linux-kernel
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 <pali@kernel.org>
Signed-off-by: Marek Behún <kabel@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
---
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
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^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH v4 4/4] PCI: mvebu: Add support for sending Set_Slot_Power_Limit message
2022-04-11 18:58 [PATCH v4 0/4] PCI: mvebu: Slot support Pali Rohár
` (2 preceding siblings ...)
2022-04-11 18:58 ` [PATCH v4 3/4] PCI: Add function for parsing 'slot-power-limit-milliwatt' DT property Pali Rohár
@ 2022-04-11 18:58 ` Pali Rohár
3 siblings, 0 replies; 5+ messages in thread
From: Pali Rohár @ 2022-04-11 18:58 UTC (permalink / raw)
To: Lorenzo Pieralisi, Bjorn Helgaas, Rob Herring, Andrew Lunn,
Thomas Petazzoni, Krzysztof Wilczyński, Marek Behún,
Russell King
Cc: linux-pci, linux-arm-kernel, linux-kernel
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@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.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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^ permalink raw reply related [flat|nested] 5+ messages in thread