[PATCH v3 4/4] pci: layerscape: add a way of specifying additional iommu mappings
laurentiu.tudor at nxp.com
laurentiu.tudor at nxp.com
Tue Aug 18 12:35:11 CEST 2020
From: Laurentiu Tudor <laurentiu.tudor at nxp.com>
In the current implementation, u-boot creates iommu mappings only
for PCI devices enumarated at boot time thus does not take into
account more dynamic scenarios such as SR-IOV or PCI hot-plug.
Add an u-boot env var and a device tree property (to be used for
example in more static scenarios such as hardwired PCI endpoints
that get initialized later in the system setup) that would allow
two things:
- for a SRIOV capable PCI EP identified by its B.D.F specify
the maximum number of VFs that will ever be created for it
- for hot-plug case, specify the B.D.F with which the device
will show up on the PCI bus
More details can be found in the included documentation:
arch/arm/cpu/armv8/fsl-layerscape/doc/README.pci_iommu_extra
Signed-off-by: Laurentiu Tudor <laurentiu.tudor at nxp.com>
---
.../fsl-layerscape/doc/README.pci_iommu_extra | 67 ++++
drivers/pci/Kconfig | 12 +
drivers/pci/pcie_layerscape_fixup.c | 328 ++++++++++++++++++
3 files changed, 407 insertions(+)
create mode 100644 arch/arm/cpu/armv8/fsl-layerscape/doc/README.pci_iommu_extra
diff --git a/arch/arm/cpu/armv8/fsl-layerscape/doc/README.pci_iommu_extra b/arch/arm/cpu/armv8/fsl-layerscape/doc/README.pci_iommu_extra
new file mode 100644
index 0000000000..43db4d8e94
--- /dev/null
+++ b/arch/arm/cpu/armv8/fsl-layerscape/doc/README.pci_iommu_extra
@@ -0,0 +1,67 @@
+#
+# Copyright 2020 NXP
+#
+# SPDX-License-Identifier: GPL-2.0+
+#
+
+Specifying extra IOMMU mappings for PCI controllers
+
+This feature can be enabled through the PCI_IOMMU_EXTRA_MAPPINGS Kconfig option.
+
+The "pci_iommu_extra" env var or "pci-iommu-extra" device tree property (to be
+used for example in more static scenarios such as hardwired PCI endpoints that
+get initialized later in the system setup) allows two things:
+ - for a SRIOV capable PCI EP identified by its B.D.F specify the maximum number
+ of VFs that will ever be created for it
+ - for hot-plug case, specify the B.D.F with which the device will show up on
+ the PCI bus
+
+The env var consists of a list of <bdf>,<action> pairs for a certain pci bus
+identified by its controller's base register address, as defined in the "reg"
+property in the device tree.
+
+pci_iommu_extra = pci@<addr1>,<bdf>,<action>,<bdf>,<action>,
+ pci@<addr2>,<bdf>,<action>,<bdf>,<action>,...
+
+where:
+ <addr> is the base register address of the pci controller for which the
+ subsequent <bdf>,<action> pairs apply
+ <bdf> identifies to which B.D.F the action applies to
+ <action> can be:
+ - "vfs=<number>" to specify that for the PCI EP identified previously by
+ the <bdf> to include mappings for <number> of VFs.
+ The variant "noari_vfs=<number>" is available to disable taking ARI into
+ account.
+ - "hp" to specify that on this <bdf> there will be a hot-plugged device so
+ it needs a mapping
+The device tree property must be placed under the correct pci controller node
+and only the bdf and action pairs need to be specified, like this:
+
+pci-iommu-extra = "<bdf>,<action>,<bdf>,<action>,...";
+
+Note: the env var has priority over the device tree property.
+
+For example, given this configuration on bus 6:
+
+=> pci 6
+Scanning PCI devices on bus 6
+BusDevFun VendorId DeviceId Device Class Sub-Class
+_____________________________________________________________
+06.00.00 0x8086 0x1572 Network controller 0x00
+06.00.01 0x8086 0x1572 Network controller 0x00
+
+The following u-boot env var will create iommu mappings for 3 VFs for each PF:
+
+=> setenv pci_iommu_extra pci at 0x3800000,6.0.0,vfs=3,6.0.1,vfs=3
+
+For the device tree case, this would be specified like this:
+
+pci-iommu-extra = "6.0.0,vfs=3,6.0.1,vfs=3";
+
+To add an iommu mapping for a hot-plugged device, please see following example:
+
+=> setenv pci_iommu_extra pci at 0x3800000,2.16.0,hp
+
+For the device tree case, this would be specified like this:
+
+pci-iommu-extra = "2.16.0,hp";
diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index 5e0a39396b..b31254bf41 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -141,6 +141,18 @@ config PCIE_LAYERSCAPE_RC
configured to Root Complex mode by clearing the corresponding bit of
RCW[HOST_AGT_PEX].
+config PCI_IOMMU_EXTRA_MAPPINGS
+ bool "Support for specifying extra IOMMU mappings for PCI"
+ depends on PCIE_LAYERSCAPE_RC
+ help
+ Enable support for specifying extra IOMMU mappings for PCI
+ controllers through a special env var called "pci_iommu_extra" or
+ through a device tree property named "pci-iommu-extra" placed in
+ the node describing the PCI controller.
+ The intent is to cover SR-IOV scenarios which need mappings for VFs
+ and PCI hot-plug scenarios. More documentation can be found under:
+ arch/arm/cpu/armv8/fsl-layerscape/doc/README.pci_iommu_extra
+
config PCIE_LAYERSCAPE_EP
bool "Layerscape PCIe Endpoint mode support"
depends on DM_PCI
diff --git a/drivers/pci/pcie_layerscape_fixup.c b/drivers/pci/pcie_layerscape_fixup.c
index 9e93841ccd..d14b4a4228 100644
--- a/drivers/pci/pcie_layerscape_fixup.c
+++ b/drivers/pci/pcie_layerscape_fixup.c
@@ -19,6 +19,8 @@
#ifdef CONFIG_ARM
#include <asm/arch/clock.h>
#endif
+#include <malloc.h>
+#include <env.h>
#include "pcie_layerscape.h"
#include "pcie_layerscape_fixup_common.h"
@@ -214,11 +216,292 @@ static int fdt_fixup_pcie_device_ls(void *blob, pci_dev_t bdf,
return 0;
}
+struct extra_iommu_entry {
+ int action;
+ pci_dev_t bdf;
+ int num_vfs;
+ bool noari;
+};
+
+#define EXTRA_IOMMU_ENTRY_HOTPLUG 1
+#define EXTRA_IOMMU_ENTRY_VFS 2
+
+static struct extra_iommu_entry *get_extra_iommu_ents(void *blob,
+ int nodeoffset,
+ phys_addr_t addr,
+ int *cnt)
+{
+ const char *s, *p, *tok;
+ struct extra_iommu_entry *entries;
+ int i = 0, b, d, f;
+
+ /*
+ * Retrieve extra IOMMU configuration from env var or from device tree.
+ * Env var is given priority.
+ */
+ s = env_get("pci_iommu_extra");
+ if (!s) {
+ s = fdt_getprop(blob, nodeoffset, "pci-iommu-extra", NULL);
+ } else {
+ phys_addr_t pci_base;
+ char *endp;
+
+ /*
+ * In env var case the config string has "pci at 0x..." in
+ * addition. Parse this part and match it by address against
+ * the input pci controller's registers base address.
+ */
+ tok = s;
+ p = strchrnul(s + 1, ',');
+ s = NULL;
+ do {
+ if (!strncmp(tok, "pci", 3)) {
+ pci_base = simple_strtoul(tok + 4, &endp, 0);
+ if (pci_base == addr) {
+ s = endp + 1;
+ break;
+ }
+ }
+ p = strchrnul(p + 1, ',');
+ tok = p + 1;
+ } while (*p);
+ }
+
+ /*
+ * If no env var or device tree property found or pci register base
+ * address mismatches, bail out
+ */
+ if (!s)
+ return NULL;
+
+ /*
+ * In order to find how many action entries to allocate, count number
+ * of actions by interating through the pairs of bdfs and actions.
+ */
+ *cnt = 0;
+ p = s;
+ while (*p && strncmp(p, "pci", 3)) {
+ if (*p == ',')
+ (*cnt)++;
+ p++;
+ }
+ if (!(*p))
+ (*cnt)++;
+
+ if (!(*cnt) || (*cnt) % 2) {
+ printf("ERROR: invalid or odd extra iommu token count %d\n",
+ *cnt);
+ return NULL;
+ }
+ *cnt = (*cnt) / 2;
+
+ entries = malloc((*cnt) * sizeof(*entries));
+ if (!entries) {
+ printf("ERROR: fail to allocate extra iommu entries\n");
+ return NULL;
+ }
+
+ /*
+ * Parse action entries one by one and store the information in the
+ * newly allocated actions array.
+ */
+ p = s;
+ while (p) {
+ /* Extract BDF */
+ b = simple_strtoul(p, (char **)&p, 0); p++;
+ d = simple_strtoul(p, (char **)&p, 0); p++;
+ f = simple_strtoul(p, (char **)&p, 0); p++;
+ entries[i].bdf = PCI_BDF(b, d, f);
+
+ /* Parse action */
+ if (!strncmp(p, "hp", 2)) {
+ /* Hot-plug entry */
+ entries[i].action = EXTRA_IOMMU_ENTRY_HOTPLUG;
+ p += 2;
+ } else if (!strncmp(p, "vfs", 3) ||
+ !strncmp(p, "noari_vfs", 9)) {
+ /* VFs or VFs with ARI disabled entry */
+ entries[i].action = EXTRA_IOMMU_ENTRY_VFS;
+ entries[i].noari = !strncmp(p, "noari_vfs", 9);
+
+ /*
+ * Parse and store total number of VFs to allocate
+ * IOMMU entries for.
+ */
+ p = strchr(p, '=');
+ entries[i].num_vfs = simple_strtoul(p + 1, (char **)&p,
+ 0);
+ if (*p)
+ p++;
+ } else {
+ printf("ERROR: invalid action in extra iommu entry\n");
+ free(entries);
+
+ return NULL;
+ }
+
+ if (!(*p) || !strncmp(p, "pci", 3))
+ break;
+
+ i++;
+ }
+
+ return entries;
+}
+
+static void get_vf_offset_and_stride(struct udevice *dev, int sriov_pos,
+ struct extra_iommu_entry *entry,
+ u16 *offset, u16 *stride)
+{
+ u16 tmp16;
+ u32 tmp32;
+ bool have_ari = false;
+ int pos;
+ struct udevice *pf_dev;
+
+ dm_pci_read_config16(dev, sriov_pos + PCI_SRIOV_TOTAL_VFS, &tmp16);
+ if (entry->num_vfs > tmp16) {
+ printf("WARN: requested no. of VFs %d exceeds total of %d\n",
+ entry->num_vfs, tmp16);
+ }
+
+ /*
+ * The code below implements the VF Discovery recomandations specified
+ * in PCIe base spec "9.2.1.2 VF Discovery", quoted below:
+ *
+ * VF Discovery
+ *
+ * The First VF Offset and VF Stride fields in the SR-IOV extended
+ * capability are 16-bit Routing ID offsets. These offsets are used to
+ * compute the Routing IDs for the VFs with the following restrictions:
+ * - The value in NumVFs in a PF (Section 9.3.3.7) may affect the
+ * values in First VF Offset (Section 9.3.3.9) and VF Stride
+ * (Section 9.3.3.10) of that PF.
+ * - The value in ARI Capable Hierarchy (Section 9.3.3.3.5) in the
+ * lowest-numbered PF of the Device (for example PF0) may affect
+ * the values in First VF Offset and VF Stride in all PFs of the
+ * Device.
+ * - NumVFs of a PF may only be changed when VF Enable
+ * (Section 9.3.3.3.1) of that PF is Clear.
+ * - ARI Capable Hierarchy (Section 9.3.3.3.5) may only be changed
+ * when VF Enable is Clear in all PFs of a Device.
+ */
+
+ /* Clear VF enable for all PFs */
+ device_foreach_child(pf_dev, dev->parent) {
+ dm_pci_read_config16(pf_dev, sriov_pos + PCI_SRIOV_CTRL,
+ &tmp16);
+ tmp16 &= ~PCI_SRIOV_CTRL_VF_EN;
+ dm_pci_write_config16(pf_dev, sriov_pos + PCI_SRIOV_CTRL,
+ tmp16);
+ }
+
+ /* Obtain a reference to PF0 device */
+ if (dm_pci_bus_find_bdf(PCI_BDF(PCI_BUS(entry->bdf),
+ PCI_DEV(entry->bdf), 0), &pf_dev)) {
+ printf("WARN: failed to get PF0\n");
+ }
+
+ if (entry->noari)
+ goto skip_ari;
+
+ /* Check that connected downstream port supports ARI Forwarding */
+ pos = dm_pci_find_capability(dev->parent, PCI_CAP_ID_EXP);
+ dm_pci_read_config32(dev->parent, pos + PCI_EXP_DEVCAP2, &tmp32);
+ if (!(tmp32 & PCI_EXP_DEVCAP2_ARI))
+ goto skip_ari;
+
+ /* Check that PF supports Alternate Routing ID */
+ if (!dm_pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ARI))
+ goto skip_ari;
+
+ /* Set ARI Capable Hierarcy for PF0 */
+ dm_pci_read_config16(pf_dev, sriov_pos + PCI_SRIOV_CTRL, &tmp16);
+ tmp16 |= PCI_SRIOV_CTRL_ARI;
+ dm_pci_write_config16(pf_dev, sriov_pos + PCI_SRIOV_CTRL, tmp16);
+ have_ari = true;
+
+skip_ari:
+ if (!have_ari) {
+ /*
+ * No ARI support or disabled so clear ARI Capable Hierarcy
+ * for PF0
+ */
+ dm_pci_read_config16(pf_dev, sriov_pos + PCI_SRIOV_CTRL,
+ &tmp16);
+ tmp16 &= ~PCI_SRIOV_CTRL_ARI;
+ dm_pci_write_config16(pf_dev, sriov_pos + PCI_SRIOV_CTRL,
+ tmp16);
+ }
+
+ /* Set requested number of VFs */
+ dm_pci_write_config16(dev, sriov_pos + PCI_SRIOV_NUM_VFS,
+ entry->num_vfs);
+
+ /* Read VF stride and offset with the configs just made */
+ dm_pci_read_config16(dev, sriov_pos + PCI_SRIOV_VF_OFFSET, offset);
+ dm_pci_read_config16(dev, sriov_pos + PCI_SRIOV_VF_STRIDE, stride);
+
+ if (have_ari) {
+ /* Reset to default ARI Capable Hierarcy bit for PF0 */
+ dm_pci_read_config16(pf_dev, sriov_pos + PCI_SRIOV_CTRL,
+ &tmp16);
+ tmp16 &= ~PCI_SRIOV_CTRL_ARI;
+ dm_pci_write_config16(pf_dev, sriov_pos + PCI_SRIOV_CTRL,
+ tmp16);
+ }
+ /* Reset to default the number of VFs */
+ dm_pci_write_config16(dev, sriov_pos + PCI_SRIOV_NUM_VFS, 0);
+}
+
+static int fdt_fixup_pci_vfs(void *blob, struct extra_iommu_entry *entry,
+ struct ls_pcie_rc *pcie_rc)
+{
+ struct udevice *dev, *bus;
+ u16 vf_offset, vf_stride;
+ int i, sriov_pos;
+ pci_dev_t bdf;
+
+ if (dm_pci_bus_find_bdf(entry->bdf, &dev)) {
+ printf("ERROR: BDF %d.%d.%d not found\n", PCI_BUS(entry->bdf),
+ PCI_DEV(entry->bdf), PCI_FUNC(entry->bdf));
+ return 0;
+ }
+
+ sriov_pos = dm_pci_find_ext_capability(dev, PCI_EXT_CAP_ID_SRIOV);
+ if (!sriov_pos) {
+ printf("WARN: trying to set VFs on non-SRIOV dev\n");
+ return 0;
+ }
+
+ get_vf_offset_and_stride(dev, sriov_pos, entry, &vf_offset, &vf_stride);
+
+ for (bus = dev; device_is_on_pci_bus(bus);)
+ bus = bus->parent;
+
+ bdf = entry->bdf - PCI_BDF(bus->seq, 0, 0) + (vf_offset << 8);
+
+ for (i = 0; i < entry->num_vfs; i++) {
+ if (fdt_fixup_pcie_device_ls(blob, bdf, pcie_rc) < 0)
+ return -1;
+ bdf += vf_stride << 8;
+ }
+
+ printf("Added %d iommu VF mappings for PF %d.%d.%d\n",
+ entry->num_vfs, PCI_BUS(entry->bdf),
+ PCI_DEV(entry->bdf), PCI_FUNC(entry->bdf));
+
+ return 0;
+}
+
static void fdt_fixup_pcie_ls(void *blob)
{
struct udevice *dev, *bus;
struct ls_pcie_rc *pcie_rc;
pci_dev_t bdf;
+ struct extra_iommu_entry *entries;
+ int i, cnt, nodeoffset;
+
/* Scan all known buses */
for (pci_find_first_device(&dev);
@@ -234,6 +517,51 @@ static void fdt_fixup_pcie_ls(void *blob)
if (fdt_fixup_pcie_device_ls(blob, bdf, pcie_rc) < 0)
break;
}
+
+ if (!IS_ENABLED(CONFIG_PCI_IOMMU_EXTRA_MAPPINGS))
+ goto skip;
+
+ list_for_each_entry(pcie_rc, &ls_pcie_list, list) {
+ nodeoffset = fdt_pcie_get_nodeoffset(blob, pcie_rc);
+ if (nodeoffset < 0) {
+ printf("ERROR: couldn't find pci node\n");
+ continue;
+ }
+
+ entries = get_extra_iommu_ents(blob, nodeoffset,
+ pcie_rc->dbi_res.start, &cnt);
+ if (!entries)
+ continue;
+
+ for (i = 0; i < cnt; i++) {
+ if (entries[i].action == EXTRA_IOMMU_ENTRY_HOTPLUG) {
+ bdf = entries[i].bdf;
+ printf("Added iommu map for hotplug %d.%d.%d\n",
+ PCI_BUS(bdf), PCI_DEV(bdf),
+ PCI_FUNC(bdf));
+ if (fdt_fixup_pcie_device_ls(blob, bdf,
+ pcie_rc) < 0) {
+ free(entries);
+ return;
+ }
+ } else if (entries[i].action == EXTRA_IOMMU_ENTRY_VFS) {
+ if (fdt_fixup_pci_vfs(blob, &entries[i],
+ pcie_rc) < 0) {
+ free(entries);
+ return;
+ }
+ } else {
+ printf("Invalid action %d for BDF %d.%d.%d\n",
+ entries[i].action,
+ PCI_BUS(entries[i].bdf),
+ PCI_DEV(entries[i].bdf),
+ PCI_FUNC(entries[i].bdf));
+ }
+ }
+ free(entries);
+ }
+
+skip:
pcie_board_fix_fdt(blob);
}
#endif
--
2.17.1
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