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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [RFC 09/29] xen/arm: Add helpers to retrieve an address from the device tree
Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
---
xen/common/device_tree.c | 343 +++++++++++++++++++++++++++++++++++++++++
xen/include/xen/device_tree.h | 22 +++
2 files changed, 365 insertions(+)
diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
index dd4b813..001188a 100644
--- a/xen/common/device_tree.c
+++ b/xen/common/device_tree.c
@@ -62,10 +62,38 @@ static void (*dt_printk)(const char *fmt, ...) =
early_printk;
#ifdef DEBUG_DT
# define dt_dprintk(fmt, args...) dt_printk(XENLOG_DEBUG fmt, ##args)
+static void dt_dump_addr(const char *s, const __be32 *addr, int na)
+{
+ dt_dprintk("%s", s);
+ while ( na-- )
+ dt_dprintk(" %08x", be32_to_cpu(*(addr++)));
+ dt_dprintk("\n");
+}
#else
# define dt_dprintk(fmt, args...) do {} while ( 0 )
+static void dt_dump_addr(const char *s, const __be32 *addr, int na) { }
#endif
+#define DT_BAD_ADDR ((u64)-1)
+
+/* Max address size we deal with */
+#define DT_MAX_ADDR_CELLS 4
+#define DT_CHECK_ADDR_COUNT(na) ((na) > 0 && (na) <= DT_MAX_ADDR_CELLS)
+#define DT_CHECK_COUNTS(na, ns) (DT_CHECK_ADDR_COUNT(na) && (ns) > 0)
+
+/* Callbacks for bus specific translators */
+struct dt_bus
+{
+ const char *name;
+ const char *addresses;
+ int (*match)(const struct dt_device_node *parent);
+ void (*count_cells)(const struct dt_device_node *child,
+ int *addrc, int *sizec);
+ u64 (*map)(__be32 *addr, const __be32 *range, int na, int ns, int
pna);
+ int (*translate)(__be32 *addr, u64 offset, int na);
+ unsigned int (*get_flags)(const __be32 *addr);
+};
+
bool_t device_tree_node_matches(const void *fdt, int node, const char *match)
{
const char *name;
@@ -704,6 +732,321 @@ int dt_n_size_cells(const struct dt_device_node *np)
return DT_ROOT_NODE_SIZE_CELLS_DEFAULT;
}
+/*
+ * Default translator (generic bus)
+ */
+static void dt_bus_default_count_cells(const struct dt_device_node *dev,
+ int *addrc, int *sizec)
+{
+ if ( addrc )
+ *addrc = dt_n_addr_cells(dev);
+ if ( sizec )
+ *sizec = dt_n_size_cells(dev);
+}
+
+static u64 dt_bus_default_map(__be32 *addr, const __be32 *range,
+ int na, int ns, int pna)
+{
+ u64 cp, s, da;
+
+ cp = dt_read_number(range, na);
+ s = dt_read_number(range + na + pna, ns);
+ da = dt_read_number(addr, na);
+
+ dt_dprintk("DT: default map, cp=%llx, s=%llx, da=%llx\n",
+ (unsigned long long)cp, (unsigned long long)s,
+ (unsigned long long)da);
+
+ /*
+ * If the number of address cells is larger than 2 we assume the
+ * mapping doesn't specify a physical address. Rather, the address
+ * specifies an identifier that must match exactly.
+ */
+ if ( na > 2 && memcmp(range, addr, na * 4) != 0 )
+ return DT_BAD_ADDR;
+
+ if ( da < cp || da >= (cp + s) )
+ return DT_BAD_ADDR;
+ return da - cp;
+}
+
+static int dt_bus_default_translate(__be32 *addr, u64 offset, int na)
+{
+ u64 a = dt_read_number(addr, na);
+
+ memset(addr, 0, na * 4);
+ a += offset;
+ if ( na > 1 )
+ addr[na - 2] = cpu_to_be32(a >> 32);
+ addr[na - 1] = cpu_to_be32(a & 0xffffffffu);
+
+ return 0;
+}
+static unsigned int dt_bus_default_get_flags(const __be32 *addr)
+{
+ /* TODO: Return the type of memory (device, ...) for caching
+ * attribute during mapping */
+ return 0;
+}
+
+/*
+ * Array of bus specific translators
+ */
+static const struct dt_bus dt_busses[] =
+{
+ /* Default */
+ {
+ .name = "default",
+ .addresses = "reg",
+ .match = NULL,
+ .count_cells = dt_bus_default_count_cells,
+ .map = dt_bus_default_map,
+ .translate = dt_bus_default_translate,
+ .get_flags = dt_bus_default_get_flags,
+ },
+};
+
+static const struct dt_bus *dt_match_bus(const struct dt_device_node *np)
+{
+ int i;
+
+ for ( i = 0; i < ARRAY_SIZE(dt_busses); i++ )
+ if ( !dt_busses[i].match || dt_busses[i].match(np) )
+ return &dt_busses[i];
+ BUG();
+
+ return NULL;
+}
+
+static const __be32 *dt_get_address(const struct dt_device_node *dev,
+ int index, u64 *size,
+ unsigned int *flags)
+{
+ const __be32 *prop;
+ u32 psize;
+ const struct dt_device_node *parent;
+ const struct dt_bus *bus;
+ int onesize, i, na, ns;
+
+ /* Get parent & match bus type */
+ parent = dt_get_parent(dev);
+ if ( parent == NULL )
+ return NULL;
+ bus = dt_match_bus(parent);
+ bus->count_cells(dev, &na, &ns);
+
+ if ( !DT_CHECK_ADDR_COUNT(na) )
+ return NULL;
+
+ /* Get "reg" or "assigned-addresses" property */
+ prop = dt_get_property(dev, bus->addresses, &psize);
+ if ( prop == NULL )
+ return NULL;
+ psize /= 4;
+
+ onesize = na + ns;
+ for ( i = 0; psize >= onesize; psize -= onesize, prop += onesize, i++ )
+ {
+ if ( i == index )
+ {
+ if ( size )
+ *size = dt_read_number(prop + na, ns);
+ if ( flags )
+ *flags = bus->get_flags(prop);
+ return prop;
+ }
+ }
+ return NULL;
+}
+
+static int dt_translate_one(const struct dt_device_node *parent,
+ const struct dt_bus *bus,
+ const struct dt_bus *pbus,
+ __be32 *addr, int na, int ns,
+ int pna, const char *rprop)
+{
+ const __be32 *ranges;
+ unsigned int rlen;
+ int rone;
+ u64 offset = DT_BAD_ADDR;
+
+ ranges = dt_get_property(parent, rprop, &rlen);
+ if ( ranges == NULL )
+ {
+ dt_printk(XENLOG_ERR "DT: no ranges; cannot translate\n");
+ return 1;
+ }
+ if ( ranges == NULL || rlen == 0 )
+ {
+ offset = dt_read_number(addr, na);
+ memset(addr, 0, pna * 4);
+ dt_dprintk("DT: empty ranges; 1:1 translation\n");
+ goto finish;
+ }
+
+ dt_dprintk("DT: walking ranges...\n");
+
+ /* Now walk through the ranges */
+ rlen /= 4;
+ rone = na + pna + ns;
+ for ( ; rlen >= rone; rlen -= rone, ranges += rone )
+ {
+ offset = bus->map(addr, ranges, na, ns, pna);
+ if ( offset != DT_BAD_ADDR )
+ break;
+ }
+ if ( offset == DT_BAD_ADDR )
+ {
+ dt_dprintk("DT: not found !\n");
+ return 1;
+ }
+ memcpy(addr, ranges + na, 4 * pna);
+
+finish:
+ dt_dump_addr("DT: parent translation for:", addr, pna);
+ dt_dprintk("DT: with offset: %llx\n", (unsigned long long)offset);
+
+ /* Translate it into parent bus space */
+ return pbus->translate(addr, offset, pna);
+}
+
+/*
+ * Translate an address from the device-tree into a CPU physical address,
+ * this walks up the tree and applies the various bus mappings on the
+ * way.
+ *
+ * Note: We consider that crossing any level with #size-cells == 0 to mean
+ * that translation is impossible (that is we are not dealing with a value
+ * that can be mapped to a cpu physical address). This is not really specified
+ * that way, but this is traditionally the way IBM at least do things
+ */
+static u64 __dt_translate_address(const struct dt_device_node *dev,
+ const __be32 *in_addr, const char *rprop)
+{
+ const struct dt_device_node *parent = NULL;
+ const struct dt_bus *bus, *pbus;
+ __be32 addr[DT_MAX_ADDR_CELLS];
+ int na, ns, pna, pns;
+ u64 result = DT_BAD_ADDR;
+
+ dt_dprintk("DT: ** translation for device %s **\n", dev->full_name);
+
+ /* Get parent & match bus type */
+ parent = dt_get_parent(dev);
+ if ( parent == NULL )
+ goto bail;
+ bus = dt_match_bus(parent);
+
+ /* Count address cells & copy address locally */
+ bus->count_cells(dev, &na, &ns);
+ if ( !DT_CHECK_COUNTS(na, ns) )
+ {
+ dt_printk(XENLOG_ERR "dt_parse: Bad cell count for %s\n",
+ dev->full_name);
+ goto bail;
+ }
+ memcpy(addr, in_addr, na * 4);
+
+ dt_dprintk("DT: bus is %s (na=%d, ns=%d) on %s\n",
+ bus->name, na, ns, parent->full_name);
+ dt_dump_addr("DT: translating address:", addr, na);
+
+ /* Translate */
+ for ( ;; )
+ {
+ /* Switch to parent bus */
+ dev = parent;
+ parent = dt_get_parent(dev);
+
+ /* If root, we have finished */
+ if ( parent == NULL )
+ {
+ dt_dprintk("DT: reached root node\n");
+ result = dt_read_number(addr, na);
+ break;
+ }
+
+ /* Get new parent bus and counts */
+ pbus = dt_match_bus(parent);
+ pbus->count_cells(dev, &pna, &pns);
+ if ( !DT_CHECK_COUNTS(pna, pns) )
+ {
+ printk(XENLOG_ERR "dt_parse: Bad cell count for %s\n",
+ dev->full_name);
+ break;
+ }
+
+ dt_dprintk("DT: parent bus is %s (na=%d, ns=%d) on %s\n",
+ pbus->name, pna, pns, parent->full_name);
+
+ /* Apply bus translation */
+ if ( dt_translate_one(dev, bus, pbus, addr, na, ns, pna, rprop) )
+ break;
+
+ /* Complete the move up one level */
+ na = pna;
+ ns = pns;
+ bus = pbus;
+
+ dt_dump_addr("DT: one level translation:", addr, na);
+ }
+
+bail:
+ return result;
+}
+
+/* dt_device_address - Translate device tree address and return it */
+int dt_device_get_address(const struct dt_device_node *dev, int index,
+ u64 *addr, u64 *size)
+{
+ const __be32 *addrp;
+ unsigned int flags;
+
+ addrp = dt_get_address(dev, index, size, &flags);
+ if ( addrp == NULL )
+ return -EINVAL;
+
+ if ( !addr )
+ return -EINVAL;
+
+ *addr = __dt_translate_address(dev, addrp, "ranges");
+
+ if ( *addr == DT_BAD_ADDR )
+ return -EINVAL;
+
+ return 0;
+}
+
+unsigned int dt_number_of_address(const struct dt_device_node *dev)
+{
+ const __be32 *prop;
+ u32 psize;
+ const struct dt_device_node *parent;
+ const struct dt_bus *bus;
+ int onesize, na, ns;
+
+ /* Get parent & match bus type */
+ parent = dt_get_parent(dev);
+ if ( parent == NULL )
+ return 0;
+
+ bus = dt_match_bus(parent);
+ bus->count_cells(dev, &na, &ns);
+
+ if ( !DT_CHECK_COUNTS(na, ns) )
+ return 0;
+
+ /* Get "reg" or "assigned-addresses" property */
+ prop = dt_get_property(dev, bus->addresses, &psize);
+ if ( prop == NULL )
+ return 0;
+
+ psize /= 4;
+ onesize = na + ns;
+
+ return (psize / onesize);
+}
+
/**
* unflatten_dt_node - Alloc and populate a device_node from the flat tree
* @fdt: The parent device tree blob
diff --git a/xen/include/xen/device_tree.h b/xen/include/xen/device_tree.h
index 9637652..020a3d0 100644
--- a/xen/include/xen/device_tree.h
+++ b/xen/include/xen/device_tree.h
@@ -278,6 +278,28 @@ struct dt_device_node *dt_find_node_by_path(const char
*path);
const struct dt_device_node *dt_get_parent(const struct dt_device_node *node);
/**
+ * dt_device_get_address - Resolve an address for a device
+ * @device: the device whose address is to be resolved
+ * @index: index of the addres to resolve
+ * @addr: address filled by this function
+ * @size: size filled by this function
+ *
+ * This function resolves an address, walking the tree, for a give
+ * device-tree node. It returns 0 on success.
+ */
+int dt_device_get_address(const struct dt_device_node *dev, int index,
+ u64 *addr, u64 *size);
+
+/**
+ * dt_number_of_address - Get the number of addresse for a device
+ * @device: the device whose number of address is to be retrieved
+ *
+ * Return the number of address for this device or 0 if there is no
+ * address or an error occured/
+ */
+unsigned int dt_number_of_address(const struct dt_device_node *device);
+
+/**
* dt_n_size_cells - Helper to retrieve the number of cell for the size
* @np: node to get the value
*
--
Julien Grall
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