[POWERPC] bootwrapper: Add dt_xlate_reg(), and use it to find serial registers.

dt_xlate_reg() uses the ranges properties of a node's parentage to find
the absolute physical address of the node's registers.

The ns16550 driver uses this when no virtual-reg property is found.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 178 insertions, 0 deletions

diff --git a/arch/powerpc/boot/devtree.c b/arch/powerpc/boot/devtree.c
index 708cadebeb46..23492d7fb556 100644
--- a/arch/powerpc/boot/devtree.c
+++ b/arch/powerpc/boot/devtree.c
@@ -109,3 +109,181 @@ void __dt_fixup_mac_addresses(u32 startindex, ...)
         }
         va_end(ap);
 }
+
+#define MAX_ADDR_CELLS 4
+#define MAX_RANGES 8
+
+static void get_reg_format(void *node, u32 *naddr, u32 *nsize)
+{
+        if (getprop(node, "#address-cells", naddr, 4) != 4)
+                *naddr = 2;
+        if (getprop(node, "#size-cells", nsize, 4) != 4)
+                *nsize = 1;
+}
+
+static void copy_val(u32 *dest, u32 *src, int naddr)
+{
+        memset(dest, 0, (MAX_ADDR_CELLS - naddr) * 4);
+        memcpy(dest, src, naddr * 4);
+}
+
+static int sub_reg(u32 *reg, u32 *sub)
+{
+        int i, borrow = 0;
+
+        for (i = 0; i < MAX_ADDR_CELLS; i++) {
+                int prev_borrow = borrow;
+                borrow = reg[i] < sub[i] + prev_borrow;
+                reg[i] -= sub[i] + prev_borrow;
+        }
+
+        return !borrow;
+}
+
+static int add_reg(u32 *reg, u32 *add)
+{
+        int i, carry = 0;
+
+        for (i = 0; i < MAX_ADDR_CELLS; i++) {
+                u64 tmp = (u64)reg[i] + add[i] + carry;
+                carry = tmp >> 32;
+                reg[i] = (u32)tmp;
+        }
+
+        return !carry;
+}
+
+/* It is assumed that if the first byte of reg fits in a
+ * range, then the whole reg block fits.
+ */
+static int compare_reg(u32 *reg, u32 *range, u32 *rangesize)
+{
+        int i;
+        u32 end;
+
+        for (i = 0; i < MAX_ADDR_CELLS; i++) {
+                if (reg[i] < range[i])
+                        return 0;
+                if (reg[i] > range[i])
+                        break;
+        }
+
+        for (i = 0; i < MAX_ADDR_CELLS; i++) {
+                end = range[i] + rangesize[i];
+
+                if (reg[i] < end)
+                        break;
+                if (reg[i] > end)
+                        return 0;
+        }
+
+        return reg[i] != end;
+}
+
+/* reg must be MAX_ADDR_CELLS */
+static int find_range(u32 *reg, u32 *ranges, int nregaddr,
+                      int naddr, int nsize, int buflen)
+{
+        int nrange = nregaddr + naddr + nsize;
+        int i;
+
+        for (i = 0; i + nrange <= buflen; i += nrange) {
+                u32 range_addr[MAX_ADDR_CELLS];
+                u32 range_size[MAX_ADDR_CELLS];
+
+                copy_val(range_addr, ranges + i, naddr);
+                copy_val(range_size, ranges + i + nregaddr + naddr, nsize);
+
+                if (compare_reg(reg, range_addr, range_size))
+                        return i;
+        }
+
+        return -1;
+}
+
+/* Currently only generic buses without special encodings are supported.
+ * In particular, PCI is not supported.  Also, only the beginning of the
+ * reg block is tracked; size is ignored except in ranges.
+ */
+int dt_xlate_reg(void *node, int res, unsigned long *addr,
+                 unsigned long *size)
+{
+        u32 last_addr[MAX_ADDR_CELLS];
+        u32 this_addr[MAX_ADDR_CELLS];
+        u32 buf[MAX_ADDR_CELLS * MAX_RANGES * 3];
+        void *parent;
+        u64 ret_addr, ret_size;
+        u32 naddr, nsize, prev_naddr;
+        int buflen, offset;
+
+        parent = get_parent(node);
+        if (!parent)
+                return 0;
+
+        get_reg_format(parent, &naddr, &nsize);
+
+        if (nsize > 2)
+                return 0;
+
+        buflen = getprop(node, "reg", buf, sizeof(buf)) / 4;
+        offset = (naddr + nsize) * res;
+
+        if (buflen < offset + naddr + nsize)
+                return 0;
+
+        copy_val(last_addr, buf + offset, naddr);
+
+        ret_size = buf[offset + naddr];
+        if (nsize == 2) {
+                ret_size <<= 32;
+                ret_size |= buf[offset + naddr + 1];
+        }
+
+        while ((node = get_parent(node))) {
+                prev_naddr = naddr;
+
+                get_reg_format(node, &naddr, &nsize);
+
+                buflen = getprop(node, "ranges", buf, sizeof(buf));
+                if (buflen < 0)
+                        continue;
+                if (buflen > sizeof(buf))
+                        return 0;
+
+                offset = find_range(last_addr, buf, prev_naddr,
+                                    naddr, nsize, buflen / 4);
+
+                if (offset < 0)
+                        return 0;
+
+                copy_val(this_addr, buf + offset, prev_naddr);
+
+                if (!sub_reg(last_addr, this_addr))
+                        return 0;
+
+                copy_val(this_addr, buf + offset + prev_naddr, naddr);
+
+                if (!add_reg(last_addr, this_addr))
+                        return 0;
+        }
+
+        if (naddr > 2)
+                return 0;
+
+        ret_addr = last_addr[0];
+        if (naddr == 2) {
+                ret_addr <<= 32;
+                ret_addr |= last_addr[1];
+        }
+
+        if (sizeof(void *) == 4 &&
+            (ret_addr >= 0x100000000ULL || ret_size > 0x100000000ULL ||
+             ret_addr + ret_size > 0x100000000ULL))
+                return 0;
+
+        *addr = ret_addr;
+        if (size)
+                *size = ret_size;
+
+        return 1;
+}