summaryrefslogtreecommitdiff
path: root/drivers/pci
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/pci')
-rw-r--r--drivers/pci/pci-sysfs.c38
-rw-r--r--drivers/pci/pci.c174
-rw-r--r--drivers/pci/pci.h21
-rw-r--r--drivers/pci/probe.c2
-rw-r--r--drivers/pci/slot.c1
5 files changed, 204 insertions, 32 deletions
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index eb6bee8724cc..63d0952684fb 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -158,45 +158,18 @@ static DEVICE_ATTR_RO(resource);
static ssize_t max_link_speed_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
- struct pci_dev *pci_dev = to_pci_dev(dev);
- u32 linkcap;
- int err;
- const char *speed;
-
- err = pcie_capability_read_dword(pci_dev, PCI_EXP_LNKCAP, &linkcap);
- if (err)
- return -EINVAL;
-
- switch (linkcap & PCI_EXP_LNKCAP_SLS) {
- case PCI_EXP_LNKCAP_SLS_8_0GB:
- speed = "8 GT/s";
- break;
- case PCI_EXP_LNKCAP_SLS_5_0GB:
- speed = "5 GT/s";
- break;
- case PCI_EXP_LNKCAP_SLS_2_5GB:
- speed = "2.5 GT/s";
- break;
- default:
- speed = "Unknown speed";
- }
+ struct pci_dev *pdev = to_pci_dev(dev);
- return sprintf(buf, "%s\n", speed);
+ return sprintf(buf, "%s\n", PCIE_SPEED2STR(pcie_get_speed_cap(pdev)));
}
static DEVICE_ATTR_RO(max_link_speed);
static ssize_t max_link_width_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
- struct pci_dev *pci_dev = to_pci_dev(dev);
- u32 linkcap;
- int err;
-
- err = pcie_capability_read_dword(pci_dev, PCI_EXP_LNKCAP, &linkcap);
- if (err)
- return -EINVAL;
+ struct pci_dev *pdev = to_pci_dev(dev);
- return sprintf(buf, "%u\n", (linkcap & PCI_EXP_LNKCAP_MLW) >> 4);
+ return sprintf(buf, "%u\n", pcie_get_width_cap(pdev));
}
static DEVICE_ATTR_RO(max_link_width);
@@ -213,6 +186,9 @@ static ssize_t current_link_speed_show(struct device *dev,
return -EINVAL;
switch (linkstat & PCI_EXP_LNKSTA_CLS) {
+ case PCI_EXP_LNKSTA_CLS_16_0GB:
+ speed = "16 GT/s";
+ break;
case PCI_EXP_LNKSTA_CLS_8_0GB:
speed = "8 GT/s";
break;
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index f6a4dd10d9b0..e7a3917ed389 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -5147,6 +5147,180 @@ int pcie_get_minimum_link(struct pci_dev *dev, enum pci_bus_speed *speed,
EXPORT_SYMBOL(pcie_get_minimum_link);
/**
+ * pcie_bandwidth_available - determine minimum link settings of a PCIe
+ * device and its bandwidth limitation
+ * @dev: PCI device to query
+ * @limiting_dev: storage for device causing the bandwidth limitation
+ * @speed: storage for speed of limiting device
+ * @width: storage for width of limiting device
+ *
+ * Walk up the PCI device chain and find the point where the minimum
+ * bandwidth is available. Return the bandwidth available there and (if
+ * limiting_dev, speed, and width pointers are supplied) information about
+ * that point. The bandwidth returned is in Mb/s, i.e., megabits/second of
+ * raw bandwidth.
+ */
+u32 pcie_bandwidth_available(struct pci_dev *dev, struct pci_dev **limiting_dev,
+ enum pci_bus_speed *speed,
+ enum pcie_link_width *width)
+{
+ u16 lnksta;
+ enum pci_bus_speed next_speed;
+ enum pcie_link_width next_width;
+ u32 bw, next_bw;
+
+ if (speed)
+ *speed = PCI_SPEED_UNKNOWN;
+ if (width)
+ *width = PCIE_LNK_WIDTH_UNKNOWN;
+
+ bw = 0;
+
+ while (dev) {
+ pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &lnksta);
+
+ next_speed = pcie_link_speed[lnksta & PCI_EXP_LNKSTA_CLS];
+ next_width = (lnksta & PCI_EXP_LNKSTA_NLW) >>
+ PCI_EXP_LNKSTA_NLW_SHIFT;
+
+ next_bw = next_width * PCIE_SPEED2MBS_ENC(next_speed);
+
+ /* Check if current device limits the total bandwidth */
+ if (!bw || next_bw <= bw) {
+ bw = next_bw;
+
+ if (limiting_dev)
+ *limiting_dev = dev;
+ if (speed)
+ *speed = next_speed;
+ if (width)
+ *width = next_width;
+ }
+
+ dev = pci_upstream_bridge(dev);
+ }
+
+ return bw;
+}
+EXPORT_SYMBOL(pcie_bandwidth_available);
+
+/**
+ * pcie_get_speed_cap - query for the PCI device's link speed capability
+ * @dev: PCI device to query
+ *
+ * Query the PCI device speed capability. Return the maximum link speed
+ * supported by the device.
+ */
+enum pci_bus_speed pcie_get_speed_cap(struct pci_dev *dev)
+{
+ u32 lnkcap2, lnkcap;
+
+ /*
+ * PCIe r4.0 sec 7.5.3.18 recommends using the Supported Link
+ * Speeds Vector in Link Capabilities 2 when supported, falling
+ * back to Max Link Speed in Link Capabilities otherwise.
+ */
+ pcie_capability_read_dword(dev, PCI_EXP_LNKCAP2, &lnkcap2);
+ if (lnkcap2) { /* PCIe r3.0-compliant */
+ if (lnkcap2 & PCI_EXP_LNKCAP2_SLS_16_0GB)
+ return PCIE_SPEED_16_0GT;
+ else if (lnkcap2 & PCI_EXP_LNKCAP2_SLS_8_0GB)
+ return PCIE_SPEED_8_0GT;
+ else if (lnkcap2 & PCI_EXP_LNKCAP2_SLS_5_0GB)
+ return PCIE_SPEED_5_0GT;
+ else if (lnkcap2 & PCI_EXP_LNKCAP2_SLS_2_5GB)
+ return PCIE_SPEED_2_5GT;
+ return PCI_SPEED_UNKNOWN;
+ }
+
+ pcie_capability_read_dword(dev, PCI_EXP_LNKCAP, &lnkcap);
+ if (lnkcap) {
+ if (lnkcap & PCI_EXP_LNKCAP_SLS_16_0GB)
+ return PCIE_SPEED_16_0GT;
+ else if (lnkcap & PCI_EXP_LNKCAP_SLS_8_0GB)
+ return PCIE_SPEED_8_0GT;
+ else if (lnkcap & PCI_EXP_LNKCAP_SLS_5_0GB)
+ return PCIE_SPEED_5_0GT;
+ else if (lnkcap & PCI_EXP_LNKCAP_SLS_2_5GB)
+ return PCIE_SPEED_2_5GT;
+ }
+
+ return PCI_SPEED_UNKNOWN;
+}
+
+/**
+ * pcie_get_width_cap - query for the PCI device's link width capability
+ * @dev: PCI device to query
+ *
+ * Query the PCI device width capability. Return the maximum link width
+ * supported by the device.
+ */
+enum pcie_link_width pcie_get_width_cap(struct pci_dev *dev)
+{
+ u32 lnkcap;
+
+ pcie_capability_read_dword(dev, PCI_EXP_LNKCAP, &lnkcap);
+ if (lnkcap)
+ return (lnkcap & PCI_EXP_LNKCAP_MLW) >> 4;
+
+ return PCIE_LNK_WIDTH_UNKNOWN;
+}
+
+/**
+ * pcie_bandwidth_capable - calculate a PCI device's link bandwidth capability
+ * @dev: PCI device
+ * @speed: storage for link speed
+ * @width: storage for link width
+ *
+ * Calculate a PCI device's link bandwidth by querying for its link speed
+ * and width, multiplying them, and applying encoding overhead. The result
+ * is in Mb/s, i.e., megabits/second of raw bandwidth.
+ */
+u32 pcie_bandwidth_capable(struct pci_dev *dev, enum pci_bus_speed *speed,
+ enum pcie_link_width *width)
+{
+ *speed = pcie_get_speed_cap(dev);
+ *width = pcie_get_width_cap(dev);
+
+ if (*speed == PCI_SPEED_UNKNOWN || *width == PCIE_LNK_WIDTH_UNKNOWN)
+ return 0;
+
+ return *width * PCIE_SPEED2MBS_ENC(*speed);
+}
+
+/**
+ * pcie_print_link_status - Report the PCI device's link speed and width
+ * @dev: PCI device to query
+ *
+ * Report the available bandwidth at the device. If this is less than the
+ * device is capable of, report the device's maximum possible bandwidth and
+ * the upstream link that limits its performance to less than that.
+ */
+void pcie_print_link_status(struct pci_dev *dev)
+{
+ enum pcie_link_width width, width_cap;
+ enum pci_bus_speed speed, speed_cap;
+ struct pci_dev *limiting_dev = NULL;
+ u32 bw_avail, bw_cap;
+
+ bw_cap = pcie_bandwidth_capable(dev, &speed_cap, &width_cap);
+ bw_avail = pcie_bandwidth_available(dev, &limiting_dev, &speed, &width);
+
+ if (bw_avail >= bw_cap)
+ pci_info(dev, "%u.%03u Gb/s available bandwidth (%s x%d link)\n",
+ bw_cap / 1000, bw_cap % 1000,
+ PCIE_SPEED2STR(speed_cap), width_cap);
+ else
+ pci_info(dev, "%u.%03u Gb/s available bandwidth, limited by %s x%d link at %s (capable of %u.%03u Gb/s with %s x%d link)\n",
+ bw_avail / 1000, bw_avail % 1000,
+ PCIE_SPEED2STR(speed), width,
+ limiting_dev ? pci_name(limiting_dev) : "<unknown>",
+ bw_cap / 1000, bw_cap % 1000,
+ PCIE_SPEED2STR(speed_cap), width_cap);
+}
+EXPORT_SYMBOL(pcie_print_link_status);
+
+/**
* pci_select_bars - Make BAR mask from the type of resource
* @dev: the PCI device for which BAR mask is made
* @flags: resource type mask to be selected
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index fcd81911b127..ce9adec6c66e 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -253,6 +253,27 @@ bool pci_bus_clip_resource(struct pci_dev *dev, int idx);
void pci_reassigndev_resource_alignment(struct pci_dev *dev);
void pci_disable_bridge_window(struct pci_dev *dev);
+/* PCIe link information */
+#define PCIE_SPEED2STR(speed) \
+ ((speed) == PCIE_SPEED_16_0GT ? "16 GT/s" : \
+ (speed) == PCIE_SPEED_8_0GT ? "8 GT/s" : \
+ (speed) == PCIE_SPEED_5_0GT ? "5 GT/s" : \
+ (speed) == PCIE_SPEED_2_5GT ? "2.5 GT/s" : \
+ "Unknown speed")
+
+/* PCIe speed to Mb/s reduced by encoding overhead */
+#define PCIE_SPEED2MBS_ENC(speed) \
+ ((speed) == PCIE_SPEED_16_0GT ? 16000*128/130 : \
+ (speed) == PCIE_SPEED_8_0GT ? 8000*128/130 : \
+ (speed) == PCIE_SPEED_5_0GT ? 5000*8/10 : \
+ (speed) == PCIE_SPEED_2_5GT ? 2500*8/10 : \
+ 0)
+
+enum pci_bus_speed pcie_get_speed_cap(struct pci_dev *dev);
+enum pcie_link_width pcie_get_width_cap(struct pci_dev *dev);
+u32 pcie_bandwidth_capable(struct pci_dev *dev, enum pci_bus_speed *speed,
+ enum pcie_link_width *width);
+
/* Single Root I/O Virtualization */
struct pci_sriov {
int pos; /* Capability position */
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index ef5377438a1e..86bf045f3d59 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -592,7 +592,7 @@ const unsigned char pcie_link_speed[] = {
PCIE_SPEED_2_5GT, /* 1 */
PCIE_SPEED_5_0GT, /* 2 */
PCIE_SPEED_8_0GT, /* 3 */
- PCI_SPEED_UNKNOWN, /* 4 */
+ PCIE_SPEED_16_0GT, /* 4 */
PCI_SPEED_UNKNOWN, /* 5 */
PCI_SPEED_UNKNOWN, /* 6 */
PCI_SPEED_UNKNOWN, /* 7 */
diff --git a/drivers/pci/slot.c b/drivers/pci/slot.c
index d10f556dc03e..191893e19d5c 100644
--- a/drivers/pci/slot.c
+++ b/drivers/pci/slot.c
@@ -76,6 +76,7 @@ static const char *pci_bus_speed_strings[] = {
"2.5 GT/s PCIe", /* 0x14 */
"5.0 GT/s PCIe", /* 0x15 */
"8.0 GT/s PCIe", /* 0x16 */
+ "16.0 GT/s PCIe", /* 0x17 */
};
static ssize_t bus_speed_read(enum pci_bus_speed speed, char *buf)
generated by cgit v1.2.3-58-ga151 (git 2.39.0) at 2024-12-12 20:08:34 +0000