[coreboot] New patch to review for coreboot: 6e237f3 Add support for enabling PCIe Common Clock and ASPM
Stefan Reinauer (stefan.reinauer@coreboot.org)
gerrit at coreboot.org
Tue Mar 6 00:53:20 CET 2012
Stefan Reinauer (stefan.reinauer at coreboot.org) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/735
-gerrit
commit 6e237f330edcfee3ec6ca0202e919ab9e2441966
Author: Duncan Laurie <dlaurie at chromium.org>
Date: Tue Oct 25 14:15:11 2011 -0700
Add support for enabling PCIe Common Clock and ASPM
These are guarded by individual Kconfig entries. The deprecated
CONFIG_PCIE_TUNING defines have been removed in favor of using specific
config options.
This is the generic half, there is board-specific pieces
still to come that tune before and after ASPM is enabled.
Change-Id: I3fe46282eada67629e9eeeed07e487dff54f2729
Signed-off-by: Duncan Laurie <dlaurie at google.com>
---
src/devices/Kconfig | 14 +++
src/devices/pciexp_device.c | 188 +++++++++++++++++++++++++++++++++++++++---
src/include/device/pci_def.h | 7 ++
src/include/device/pciexp.h | 7 ++
4 files changed, 205 insertions(+), 11 deletions(-)
diff --git a/src/devices/Kconfig b/src/devices/Kconfig
index 98e8d9f..7429bda 100644
--- a/src/devices/Kconfig
+++ b/src/devices/Kconfig
@@ -163,3 +163,17 @@ config AGP_PLUGIN_SUPPORT
config CARDBUS_PLUGIN_SUPPORT
bool
default y
+
+config PCIEXP_COMMON_CLOCK
+ prompt "Enable PCIe Common Clock"
+ bool
+ default n
+ help
+ Detect and enable Common Clock on PCIe links.
+
+config PCIEXP_ASPM
+ prompt "Enable PCIe ASPM"
+ bool
+ default n
+ help
+ Detect and enable ASPM on PCIe links.
diff --git a/src/devices/pciexp_device.c b/src/devices/pciexp_device.c
index 5d33942..36f3e6a 100644
--- a/src/devices/pciexp_device.c
+++ b/src/devices/pciexp_device.c
@@ -19,31 +19,197 @@
*/
#include <console/console.h>
+#include <delay.h>
#include <device/device.h>
#include <device/pci.h>
#include <device/pci_ids.h>
#include <device/pciexp.h>
+#if CONFIG_PCIEXP_COMMON_CLOCK
+/*
+ * Re-train a PCIe link
+ */
+#define PCIE_TRAIN_RETRY 10000
+static int pciexp_retrain_link(device_t dev, unsigned cap)
+{
+ unsigned try = PCIE_TRAIN_RETRY;
+ u16 lnk;
+
+ /* Start link retraining */
+ lnk = pci_read_config16(dev, cap + PCI_EXP_LNKCTL);
+ lnk |= PCI_EXP_LNKCTL_RL;
+ pci_write_config16(dev, cap + PCI_EXP_LNKCTL, lnk);
+
+ /* Wait for training to complete */
+ while (try--) {
+ lnk = pci_read_config16(dev, cap + PCI_EXP_LNKSTA);
+ if (!(lnk & PCI_EXP_LNKSTA_LT))
+ return 0;
+ udelay(100);
+ }
+
+ printk(BIOS_ERR, "%s: Link Retrain timeout\n", dev_path(dev));
+ return -1;
+}
+
+/*
+ * Check the Slot Clock Configuration for root port and endpoint
+ * and enable Common Clock Configuration if possible. If CCC is
+ * enabled the link must be retrained.
+ */
+static void pciexp_enable_common_clock(device_t root, unsigned root_cap,
+ device_t endp, unsigned endp_cap)
+{
+ u16 root_scc, endp_scc, lnkctl;
+
+ /* Get Slot Clock Configuration for root port */
+ root_scc = pci_read_config16(root, root_cap + PCI_EXP_LNKSTA);
+ root_scc &= PCI_EXP_LNKSTA_SLC;
+
+ /* Get Slot Clock Configuration for endpoint */
+ endp_scc = pci_read_config16(endp, endp_cap + PCI_EXP_LNKSTA);
+ endp_scc &= PCI_EXP_LNKSTA_SLC;
+
+ /* Enable Common Clock Configuration and retrain */
+ if (root_scc && endp_scc) {
+ printk(BIOS_INFO, "Enabling Common Clock Configuration\n");
+
+ /* Set in endpoint */
+ lnkctl = pci_read_config16(endp, endp_cap + PCI_EXP_LNKCTL);
+ lnkctl |= PCI_EXP_LNKCTL_CCC;
+ pci_write_config16(endp, endp_cap + PCI_EXP_LNKCTL, lnkctl);
+
+ /* Set in root port */
+ lnkctl = pci_read_config16(root, root_cap + PCI_EXP_LNKCTL);
+ lnkctl |= PCI_EXP_LNKCTL_CCC;
+ pci_write_config16(root, root_cap + PCI_EXP_LNKCTL, lnkctl);
+
+ /* Retrain link if CCC was enabled */
+ pciexp_retrain_link(root, root_cap);
+ }
+}
+#endif /* CONFIG_PCIEXP_COMMON_CLOCK */
+
+#if CONFIG_PCIEXP_ASPM
+/*
+ * Determine the ASPM L0s or L1 exit latency for a link
+ * by checking both root port and endpoint and returning
+ * the highest latency value.
+ */
+static int pciexp_aspm_latency(device_t root, unsigned root_cap,
+ device_t endp, unsigned endp_cap,
+ enum aspm_type type)
+{
+ int root_lat = 0, endp_lat = 0;
+ u32 root_lnkcap, endp_lnkcap;
+
+ root_lnkcap = pci_read_config32(root, root_cap + PCI_EXP_LNKCAP);
+ endp_lnkcap = pci_read_config32(endp, endp_cap + PCI_EXP_LNKCAP);
+
+ /* Make sure the link supports this ASPM type by checking
+ * capability bits 11:10 with aspm_type offset by 1 */
+ if (!(root_lnkcap & (1 << (type + 9))) ||
+ !(endp_lnkcap & (1 << (type + 9))))
+ return -1;
+
+ /* Find the one with higher latency */
+ switch (type) {
+ case PCIE_ASPM_L0S:
+ root_lat = (root_lnkcap & PCI_EXP_LNKCAP_L0SEL) >> 12;
+ endp_lat = (endp_lnkcap & PCI_EXP_LNKCAP_L0SEL) >> 12;
+ break;
+ case PCIE_ASPM_L1:
+ root_lat = (root_lnkcap & PCI_EXP_LNKCAP_L1EL) >> 15;
+ endp_lat = (endp_lnkcap & PCI_EXP_LNKCAP_L1EL) >> 15;
+ break;
+ default:
+ return -1;
+ }
+
+ return (endp_lat > root_lat) ? endp_lat : root_lat;
+}
+
+/*
+ * Enable ASPM on PCIe root port and endpoint.
+ *
+ * Returns APMC value:
+ * -1 = Error
+ * 0 = no ASPM
+ * 1 = L0s Enabled
+ * 2 = L1 Enabled
+ * 3 = L0s and L1 Enabled
+ */
+static enum aspm_type pciexp_enable_aspm(device_t root, unsigned root_cap,
+ device_t endp, unsigned endp_cap)
+{
+ const char *aspm_type_str[] = { "None", "L0s", "L1", "L0s and L1" };
+ enum aspm_type apmc = PCIE_ASPM_NONE;
+ int exit_latency, ok_latency;
+ u16 lnkctl;
+ u32 devcap;
+
+ /* Get endpoint device capabilities for acceptable limits */
+ devcap = pci_read_config32(endp, endp_cap + PCI_EXP_DEVCAP);
+
+ /* Enable L0s if it is within endpoint acceptable limit */
+ ok_latency = (devcap & PCI_EXP_DEVCAP_L0S) >> 6;
+ exit_latency = pciexp_aspm_latency(root, root_cap, endp, endp_cap,
+ PCIE_ASPM_L0S);
+ if (exit_latency >= 0 && exit_latency <= ok_latency)
+ apmc |= PCIE_ASPM_L0S;
+
+ /* Enable L1 if it is within endpoint acceptable limit */
+ ok_latency = (devcap & PCI_EXP_DEVCAP_L1) >> 9;
+ exit_latency = pciexp_aspm_latency(root, root_cap, endp, endp_cap,
+ PCIE_ASPM_L1);
+ if (exit_latency >= 0 && exit_latency <= ok_latency)
+ apmc |= PCIE_ASPM_L1;
+
+ if (apmc != PCIE_ASPM_NONE) {
+ /* Set APMC in root port first */
+ lnkctl = pci_read_config16(root, root_cap + PCI_EXP_LNKCTL);
+ lnkctl |= apmc;
+ pci_write_config16(root, root_cap + PCI_EXP_LNKCTL, lnkctl);
+
+ /* Set APMC in endpoint device next */
+ lnkctl = pci_read_config16(endp, endp_cap + PCI_EXP_LNKCTL);
+ lnkctl |= apmc;
+ pci_write_config16(endp, endp_cap + PCI_EXP_LNKCTL, lnkctl);
+ }
+
+ printk(BIOS_INFO, "ASPM: Enabled %s\n", aspm_type_str[apmc]);
+ return apmc;
+}
+#endif /* CONFIG_PCIEXP_ASPM */
+
static void pciexp_tune_dev(device_t dev)
{
- unsigned int cap;
-#if CONFIG_PCIE_TUNING
- u32 reg32;
-#endif
+ device_t root = dev->bus->dev;
+ unsigned int root_cap, cap;
cap = pci_find_capability(dev, PCI_CAP_ID_PCIE);
if (!cap)
return;
-#if CONFIG_PCIE_TUNING
- printk(BIOS_DEBUG, "PCIe: tuning %s\n", dev_path(dev));
+ root_cap = pci_find_capability(root, PCI_CAP_ID_PCIE);
+ if (!root_cap)
+ return;
+
+#if CONFIG_PCIEXP_COMMON_CLOCK
+ /* Check for and enable Common Clock */
+ pciexp_enable_common_clock(root, root_cap, dev, cap);
+#endif
- // TODO make this depending on ASPM.
+#if CONFIG_PCIEXP_ASPM
+ /* Check for and enable ASPM */
+ enum aspm_type apmc = pciexp_enable_aspm(root, root_cap, dev, cap);
- /* Enable ASPM role based error reporting. */
- reg32 = pci_read_config32(dev, cap + PCI_EXP_DEVCAP);
- reg32 |= PCI_EXP_DEVCAP_RBER;
- pci_write_config32(dev, cap + PCI_EXP_DEVCAP, reg32);
+ if (apmc != PCIE_ASPM_NONE) {
+ /* Enable ASPM role based error reporting. */
+ u32 reg32 = pci_read_config32(dev, cap + PCI_EXP_DEVCAP);
+ reg32 |= PCI_EXP_DEVCAP_RBER;
+ pci_write_config32(dev, cap + PCI_EXP_DEVCAP, reg32);
+ }
#endif
}
diff --git a/src/include/device/pci_def.h b/src/include/device/pci_def.h
index a5aa3a1..58a7321 100644
--- a/src/include/device/pci_def.h
+++ b/src/include/device/pci_def.h
@@ -371,8 +371,15 @@
#define PCI_EXP_DEVSTA_AUXPD 0x10 /* AUX Power Detected */
#define PCI_EXP_DEVSTA_TRPND 0x20 /* Transactions Pending */
#define PCI_EXP_LNKCAP 12 /* Link Capabilities */
+#define PCI_EXP_LNKCAP_ASPMS 0xc00 /* ASPM Support */
+#define PCI_EXP_LNKCAP_L0SEL 0x7000 /* L0s Exit Latency */
+#define PCI_EXP_LNKCAP_L1EL 0x38000 /* L1 Exit Latency */
#define PCI_EXP_LNKCTL 16 /* Link Control */
+#define PCI_EXP_LNKCTL_RL 0x20 /* Retrain Link */
+#define PCI_EXP_LNKCTL_CCC 0x40 /* Common Clock COnfiguration */
#define PCI_EXP_LNKSTA 18 /* Link Status */
+#define PCI_EXP_LNKSTA_LT 0x800 /* Link Training */
+#define PCI_EXP_LNKSTA_SLC 0x1000 /* Slot Clock Configuration */
#define PCI_EXP_SLTCAP 20 /* Slot Capabilities */
#define PCI_EXP_SLTCTL 24 /* Slot Control */
#define PCI_EXP_SLTSTA 26 /* Slot Status */
diff --git a/src/include/device/pciexp.h b/src/include/device/pciexp.h
index 409f211..87a5002 100644
--- a/src/include/device/pciexp.h
+++ b/src/include/device/pciexp.h
@@ -2,6 +2,13 @@
#define DEVICE_PCIEXP_H
/* (c) 2005 Linux Networx GPL see COPYING for details */
+enum aspm_type {
+ PCIE_ASPM_NONE = 0,
+ PCIE_ASPM_L0S = 1,
+ PCIE_ASPM_L1 = 2,
+ PCIE_ASPM_BOTH = 3,
+};
+
unsigned int pciexp_scan_bus(struct bus *bus, unsigned int min_devfn,
unsigned int max_devfn, unsigned int max);
unsigned int pciexp_scan_bridge(device_t dev, unsigned int max);
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