// Copyright 2017 IBM Corp.
#include <asm/pnv-ocxl.h>
#include <asm/opal.h>
+#include <misc/ocxl-config.h>
#include "pci.h"
#define PNV_OCXL_TL_P9_RECV_CAP 0x000000000000000Full
+#define PNV_OCXL_ACTAG_MAX 64
/* PASIDs are 20-bit, but on P9, NPU can only handle 15 bits */
#define PNV_OCXL_PASID_BITS 15
#define PNV_OCXL_PASID_MAX ((1 << PNV_OCXL_PASID_BITS) - 1)
+#define AFU_PRESENT (1 << 31)
+#define AFU_INDEX_MASK 0x3F000000
+#define AFU_INDEX_SHIFT 24
+#define ACTAG_MASK 0xFFF
+
+
+struct actag_range {
+ u16 start;
+ u16 count;
+};
+
+struct npu_link {
+ struct list_head list;
+ int domain;
+ int bus;
+ int dev;
+ u16 fn_desired_actags[8];
+ struct actag_range fn_actags[8];
+ bool assignment_done;
+};
+static struct list_head links_list = LIST_HEAD_INIT(links_list);
+static DEFINE_MUTEX(links_list_lock);
+
+
+/*
+ * opencapi actags handling:
+ *
+ * When sending commands, the opencapi device references the memory
+ * context it's targeting with an 'actag', which is really an alias
+ * for a (BDF, pasid) combination. When it receives a command, the NPU
+ * must do a lookup of the actag to identify the memory context. The
+ * hardware supports a finite number of actags per link (64 for
+ * POWER9).
+ *
+ * The device can carry multiple functions, and each function can have
+ * multiple AFUs. Each AFU advertises in its config space the number
+ * of desired actags. The host must configure in the config space of
+ * the AFU how many actags the AFU is really allowed to use (which can
+ * be less than what the AFU desires).
+ *
+ * When a PCI function is probed by the driver, it has no visibility
+ * about the other PCI functions and how many actags they'd like,
+ * which makes it impossible to distribute actags fairly among AFUs.
+ *
+ * Unfortunately, the only way to know how many actags a function
+ * desires is by looking at the data for each AFU in the config space
+ * and add them up. Similarly, the only way to know how many actags
+ * all the functions of the physical device desire is by adding the
+ * previously computed function counts. Then we can match that against
+ * what the hardware supports.
+ *
+ * To get a comprehensive view, we use a 'pci fixup': at the end of
+ * PCI enumeration, each function counts how many actags its AFUs
+ * desire and we save it in a 'npu_link' structure, shared between all
+ * the PCI functions of a same device. Therefore, when the first
+ * function is probed by the driver, we can get an idea of the total
+ * count of desired actags for the device, and assign the actags to
+ * the AFUs, by pro-rating if needed.
+ */
+
+static int find_dvsec_from_pos(struct pci_dev *dev, int dvsec_id, int pos)
+{
+ int vsec = pos;
+ u16 vendor, id;
+
+ while ((vsec = pci_find_next_ext_capability(dev, vsec,
+ OCXL_EXT_CAP_ID_DVSEC))) {
+ pci_read_config_word(dev, vsec + OCXL_DVSEC_VENDOR_OFFSET,
+ &vendor);
+ pci_read_config_word(dev, vsec + OCXL_DVSEC_ID_OFFSET, &id);
+ if (vendor == PCI_VENDOR_ID_IBM && id == dvsec_id)
+ return vsec;
+ }
+ return 0;
+}
+
+static int find_dvsec_afu_ctrl(struct pci_dev *dev, u8 afu_idx)
+{
+ int vsec = 0;
+ u8 idx;
+
+ while ((vsec = find_dvsec_from_pos(dev, OCXL_DVSEC_AFU_CTRL_ID,
+ vsec))) {
+ pci_read_config_byte(dev, vsec + OCXL_DVSEC_AFU_CTRL_AFU_IDX,
+ &idx);
+ if (idx == afu_idx)
+ return vsec;
+ }
+ return 0;
+}
+
+static int get_max_afu_index(struct pci_dev *dev, int *afu_idx)
+{
+ int pos;
+ u32 val;
+
+ pos = find_dvsec_from_pos(dev, OCXL_DVSEC_FUNC_ID, 0);
+ if (!pos)
+ return -ESRCH;
+
+ pci_read_config_dword(dev, pos + OCXL_DVSEC_FUNC_OFF_INDEX, &val);
+ if (val & AFU_PRESENT)
+ *afu_idx = (val & AFU_INDEX_MASK) >> AFU_INDEX_SHIFT;
+ else
+ *afu_idx = -1;
+ return 0;
+}
+
+static int get_actag_count(struct pci_dev *dev, int afu_idx, int *actag)
+{
+ int pos;
+ u16 actag_sup;
+
+ pos = find_dvsec_afu_ctrl(dev, afu_idx);
+ if (!pos)
+ return -ESRCH;
+
+ pci_read_config_word(dev, pos + OCXL_DVSEC_AFU_CTRL_ACTAG_SUP,
+ &actag_sup);
+ *actag = actag_sup & ACTAG_MASK;
+ return 0;
+}
+
+static struct npu_link *find_link(struct pci_dev *dev)
+{
+ struct npu_link *link;
+
+ list_for_each_entry(link, &links_list, list) {
+ /* The functions of a device all share the same link */
+ if (link->domain == pci_domain_nr(dev->bus) &&
+ link->bus == dev->bus->number &&
+ link->dev == PCI_SLOT(dev->devfn)) {
+ return link;
+ }
+ }
+
+ /* link doesn't exist yet. Allocate one */
+ link = kzalloc(sizeof(struct npu_link), GFP_KERNEL);
+ if (!link)
+ return NULL;
+ link->domain = pci_domain_nr(dev->bus);
+ link->bus = dev->bus->number;
+ link->dev = PCI_SLOT(dev->devfn);
+ list_add(&link->list, &links_list);
+ return link;
+}
+
+static void pnv_ocxl_fixup_actag(struct pci_dev *dev)
+{
+ struct pci_controller *hose = pci_bus_to_host(dev->bus);
+ struct pnv_phb *phb = hose->private_data;
+ struct npu_link *link;
+ int rc, afu_idx = -1, i, actag;
+
+ if (!machine_is(powernv))
+ return;
+
+ if (phb->type != PNV_PHB_NPU_OCAPI)
+ return;
+
+ mutex_lock(&links_list_lock);
+
+ link = find_link(dev);
+ if (!link) {
+ dev_warn(&dev->dev, "couldn't update actag information\n");
+ mutex_unlock(&links_list_lock);
+ return;
+ }
+
+ /*
+ * Check how many actags are desired for the AFUs under that
+ * function and add it to the count for the link
+ */
+ rc = get_max_afu_index(dev, &afu_idx);
+ if (rc) {
+ /* Most likely an invalid config space */
+ dev_dbg(&dev->dev, "couldn't find AFU information\n");
+ afu_idx = -1;
+ }
+
+ link->fn_desired_actags[PCI_FUNC(dev->devfn)] = 0;
+ for (i = 0; i <= afu_idx; i++) {
+ /*
+ * AFU index 'holes' are allowed. So don't fail if we
+ * can't read the actag info for an index
+ */
+ rc = get_actag_count(dev, i, &actag);
+ if (rc)
+ continue;
+ link->fn_desired_actags[PCI_FUNC(dev->devfn)] += actag;
+ }
+ dev_dbg(&dev->dev, "total actags for function: %d\n",
+ link->fn_desired_actags[PCI_FUNC(dev->devfn)]);
+
+ mutex_unlock(&links_list_lock);
+}
+DECLARE_PCI_FIXUP_HEADER(PCI_ANY_ID, PCI_ANY_ID, pnv_ocxl_fixup_actag);
+
+static u16 assign_fn_actags(u16 desired, u16 total)
+{
+ u16 count;
+
+ if (total <= PNV_OCXL_ACTAG_MAX)
+ count = desired;
+ else
+ count = PNV_OCXL_ACTAG_MAX * desired / total;
+
+ return count;
+}
+
+static void assign_actags(struct npu_link *link)
+{
+ u16 actag_count, range_start = 0, total_desired = 0;
+ int i;
+
+ for (i = 0; i < 8; i++)
+ total_desired += link->fn_desired_actags[i];
+
+ for (i = 0; i < 8; i++) {
+ if (link->fn_desired_actags[i]) {
+ actag_count = assign_fn_actags(
+ link->fn_desired_actags[i],
+ total_desired);
+ link->fn_actags[i].start = range_start;
+ link->fn_actags[i].count = actag_count;
+ range_start += actag_count;
+ WARN_ON(range_start >= PNV_OCXL_ACTAG_MAX);
+ }
+ pr_debug("link %x:%x:%x fct %d actags: start=%d count=%d (desired=%d)\n",
+ link->domain, link->bus, link->dev, i,
+ link->fn_actags[i].start, link->fn_actags[i].count,
+ link->fn_desired_actags[i]);
+ }
+ link->assignment_done = true;
+}
+
+int pnv_ocxl_get_actag(struct pci_dev *dev, u16 *base, u16 *enabled,
+ u16 *supported)
+{
+ struct npu_link *link;
+
+ mutex_lock(&links_list_lock);
+
+ link = find_link(dev);
+ if (!link) {
+ dev_err(&dev->dev, "actag information not found\n");
+ mutex_unlock(&links_list_lock);
+ return -ENODEV;
+ }
+ /*
+ * On p9, we only have 64 actags per link, so they must be
+ * shared by all the functions of the same adapter. We counted
+ * the desired actag counts during PCI enumeration, so that we
+ * can allocate a pro-rated number of actags to each function.
+ */
+ if (!link->assignment_done)
+ assign_actags(link);
+
+ *base = link->fn_actags[PCI_FUNC(dev->devfn)].start;
+ *enabled = link->fn_actags[PCI_FUNC(dev->devfn)].count;
+ *supported = link->fn_desired_actags[PCI_FUNC(dev->devfn)];
+
+ mutex_unlock(&links_list_lock);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(pnv_ocxl_get_actag);
+
+int pnv_ocxl_get_pasid_count(struct pci_dev *dev, int *count)
+{
+ struct npu_link *link;
+ int i, rc = -EINVAL;
+
+ /*
+ * The number of PASIDs (process address space ID) which can
+ * be used by a function depends on how many functions exist
+ * on the device. The NPU needs to be configured to know how
+ * many bits are available to PASIDs and how many are to be
+ * used by the function BDF indentifier.
+ *
+ * We only support one AFU-carrying function for now.
+ */
+ mutex_lock(&links_list_lock);
+
+ link = find_link(dev);
+ if (!link) {
+ dev_err(&dev->dev, "actag information not found\n");
+ mutex_unlock(&links_list_lock);
+ return -ENODEV;
+ }
+
+ for (i = 0; i < 8; i++)
+ if (link->fn_desired_actags[i] && (i == PCI_FUNC(dev->devfn))) {
+ *count = PNV_OCXL_PASID_MAX;
+ rc = 0;
+ break;
+ }
+
+ mutex_unlock(&links_list_lock);
+ dev_dbg(&dev->dev, "%d PASIDs available for function\n",
+ rc ? 0 : *count);
+ return rc;
+}
+EXPORT_SYMBOL_GPL(pnv_ocxl_get_pasid_count);
static void set_templ_rate(unsigned int templ, unsigned int rate, char *buf)
{
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