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path: root/drivers/clk/bcm/clk-kona-setup.c
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-rw-r--r--drivers/clk/bcm/clk-kona-setup.c769
1 files changed, 769 insertions, 0 deletions
diff --git a/drivers/clk/bcm/clk-kona-setup.c b/drivers/clk/bcm/clk-kona-setup.c
new file mode 100644
index 000000000000..c7607feb18dd
--- /dev/null
+++ b/drivers/clk/bcm/clk-kona-setup.c
@@ -0,0 +1,769 @@
+/*
+ * Copyright (C) 2013 Broadcom Corporation
+ * Copyright 2013 Linaro Limited
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/io.h>
+#include <linux/of_address.h>
+
+#include "clk-kona.h"
+
+/* These are used when a selector or trigger is found to be unneeded */
+#define selector_clear_exists(sel) ((sel)->width = 0)
+#define trigger_clear_exists(trig) FLAG_CLEAR(trig, TRIG, EXISTS)
+
+LIST_HEAD(ccu_list); /* The list of set up CCUs */
+
+/* Validity checking */
+
+static bool clk_requires_trigger(struct kona_clk *bcm_clk)
+{
+ struct peri_clk_data *peri = bcm_clk->peri;
+ struct bcm_clk_sel *sel;
+ struct bcm_clk_div *div;
+
+ if (bcm_clk->type != bcm_clk_peri)
+ return false;
+
+ sel = &peri->sel;
+ if (sel->parent_count && selector_exists(sel))
+ return true;
+
+ div = &peri->div;
+ if (!divider_exists(div))
+ return false;
+
+ /* Fixed dividers don't need triggers */
+ if (!divider_is_fixed(div))
+ return true;
+
+ div = &peri->pre_div;
+
+ return divider_exists(div) && !divider_is_fixed(div);
+}
+
+static bool peri_clk_data_offsets_valid(struct kona_clk *bcm_clk)
+{
+ struct peri_clk_data *peri;
+ struct bcm_clk_gate *gate;
+ struct bcm_clk_div *div;
+ struct bcm_clk_sel *sel;
+ struct bcm_clk_trig *trig;
+ const char *name;
+ u32 range;
+ u32 limit;
+
+ BUG_ON(bcm_clk->type != bcm_clk_peri);
+ peri = bcm_clk->peri;
+ name = bcm_clk->name;
+ range = bcm_clk->ccu->range;
+
+ limit = range - sizeof(u32);
+ limit = round_down(limit, sizeof(u32));
+
+ gate = &peri->gate;
+ if (gate_exists(gate)) {
+ if (gate->offset > limit) {
+ pr_err("%s: bad gate offset for %s (%u > %u)\n",
+ __func__, name, gate->offset, limit);
+ return false;
+ }
+ }
+
+ div = &peri->div;
+ if (divider_exists(div)) {
+ if (div->offset > limit) {
+ pr_err("%s: bad divider offset for %s (%u > %u)\n",
+ __func__, name, div->offset, limit);
+ return false;
+ }
+ }
+
+ div = &peri->pre_div;
+ if (divider_exists(div)) {
+ if (div->offset > limit) {
+ pr_err("%s: bad pre-divider offset for %s "
+ "(%u > %u)\n",
+ __func__, name, div->offset, limit);
+ return false;
+ }
+ }
+
+ sel = &peri->sel;
+ if (selector_exists(sel)) {
+ if (sel->offset > limit) {
+ pr_err("%s: bad selector offset for %s (%u > %u)\n",
+ __func__, name, sel->offset, limit);
+ return false;
+ }
+ }
+
+ trig = &peri->trig;
+ if (trigger_exists(trig)) {
+ if (trig->offset > limit) {
+ pr_err("%s: bad trigger offset for %s (%u > %u)\n",
+ __func__, name, trig->offset, limit);
+ return false;
+ }
+ }
+
+ trig = &peri->pre_trig;
+ if (trigger_exists(trig)) {
+ if (trig->offset > limit) {
+ pr_err("%s: bad pre-trigger offset for %s (%u > %u)\n",
+ __func__, name, trig->offset, limit);
+ return false;
+ }
+ }
+
+ return true;
+}
+
+/* A bit position must be less than the number of bits in a 32-bit register. */
+static bool bit_posn_valid(u32 bit_posn, const char *field_name,
+ const char *clock_name)
+{
+ u32 limit = BITS_PER_BYTE * sizeof(u32) - 1;
+
+ if (bit_posn > limit) {
+ pr_err("%s: bad %s bit for %s (%u > %u)\n", __func__,
+ field_name, clock_name, bit_posn, limit);
+ return false;
+ }
+ return true;
+}
+
+/*
+ * A bitfield must be at least 1 bit wide. Both the low-order and
+ * high-order bits must lie within a 32-bit register. We require
+ * fields to be less than 32 bits wide, mainly because we use
+ * shifting to produce field masks, and shifting a full word width
+ * is not well-defined by the C standard.
+ */
+static bool bitfield_valid(u32 shift, u32 width, const char *field_name,
+ const char *clock_name)
+{
+ u32 limit = BITS_PER_BYTE * sizeof(u32);
+
+ if (!width) {
+ pr_err("%s: bad %s field width 0 for %s\n", __func__,
+ field_name, clock_name);
+ return false;
+ }
+ if (shift + width > limit) {
+ pr_err("%s: bad %s for %s (%u + %u > %u)\n", __func__,
+ field_name, clock_name, shift, width, limit);
+ return false;
+ }
+ return true;
+}
+
+/*
+ * All gates, if defined, have a status bit, and for hardware-only
+ * gates, that's it. Gates that can be software controlled also
+ * have an enable bit. And a gate that can be hardware or software
+ * controlled will have a hardware/software select bit.
+ */
+static bool gate_valid(struct bcm_clk_gate *gate, const char *field_name,
+ const char *clock_name)
+{
+ if (!bit_posn_valid(gate->status_bit, "gate status", clock_name))
+ return false;
+
+ if (gate_is_sw_controllable(gate)) {
+ if (!bit_posn_valid(gate->en_bit, "gate enable", clock_name))
+ return false;
+
+ if (gate_is_hw_controllable(gate)) {
+ if (!bit_posn_valid(gate->hw_sw_sel_bit,
+ "gate hw/sw select",
+ clock_name))
+ return false;
+ }
+ } else {
+ BUG_ON(!gate_is_hw_controllable(gate));
+ }
+
+ return true;
+}
+
+/*
+ * A selector bitfield must be valid. Its parent_sel array must
+ * also be reasonable for the field.
+ */
+static bool sel_valid(struct bcm_clk_sel *sel, const char *field_name,
+ const char *clock_name)
+{
+ if (!bitfield_valid(sel->shift, sel->width, field_name, clock_name))
+ return false;
+
+ if (sel->parent_count) {
+ u32 max_sel;
+ u32 limit;
+
+ /*
+ * Make sure the selector field can hold all the
+ * selector values we expect to be able to use. A
+ * clock only needs to have a selector defined if it
+ * has more than one parent. And in that case the
+ * highest selector value will be in the last entry
+ * in the array.
+ */
+ max_sel = sel->parent_sel[sel->parent_count - 1];
+ limit = (1 << sel->width) - 1;
+ if (max_sel > limit) {
+ pr_err("%s: bad selector for %s "
+ "(%u needs > %u bits)\n",
+ __func__, clock_name, max_sel,
+ sel->width);
+ return false;
+ }
+ } else {
+ pr_warn("%s: ignoring selector for %s (no parents)\n",
+ __func__, clock_name);
+ selector_clear_exists(sel);
+ kfree(sel->parent_sel);
+ sel->parent_sel = NULL;
+ }
+
+ return true;
+}
+
+/*
+ * A fixed divider just needs to be non-zero. A variable divider
+ * has to have a valid divider bitfield, and if it has a fraction,
+ * the width of the fraction must not be no more than the width of
+ * the divider as a whole.
+ */
+static bool div_valid(struct bcm_clk_div *div, const char *field_name,
+ const char *clock_name)
+{
+ if (divider_is_fixed(div)) {
+ /* Any fixed divider value but 0 is OK */
+ if (div->fixed == 0) {
+ pr_err("%s: bad %s fixed value 0 for %s\n", __func__,
+ field_name, clock_name);
+ return false;
+ }
+ return true;
+ }
+ if (!bitfield_valid(div->shift, div->width, field_name, clock_name))
+ return false;
+
+ if (divider_has_fraction(div))
+ if (div->frac_width > div->width) {
+ pr_warn("%s: bad %s fraction width for %s (%u > %u)\n",
+ __func__, field_name, clock_name,
+ div->frac_width, div->width);
+ return false;
+ }
+
+ return true;
+}
+
+/*
+ * If a clock has two dividers, the combined number of fractional
+ * bits must be representable in a 32-bit unsigned value. This
+ * is because we scale up a dividend using both dividers before
+ * dividing to improve accuracy, and we need to avoid overflow.
+ */
+static bool kona_dividers_valid(struct kona_clk *bcm_clk)
+{
+ struct peri_clk_data *peri = bcm_clk->peri;
+ struct bcm_clk_div *div;
+ struct bcm_clk_div *pre_div;
+ u32 limit;
+
+ BUG_ON(bcm_clk->type != bcm_clk_peri);
+
+ if (!divider_exists(&peri->div) || !divider_exists(&peri->pre_div))
+ return true;
+
+ div = &peri->div;
+ pre_div = &peri->pre_div;
+ if (divider_is_fixed(div) || divider_is_fixed(pre_div))
+ return true;
+
+ limit = BITS_PER_BYTE * sizeof(u32);
+
+ return div->frac_width + pre_div->frac_width <= limit;
+}
+
+
+/* A trigger just needs to represent a valid bit position */
+static bool trig_valid(struct bcm_clk_trig *trig, const char *field_name,
+ const char *clock_name)
+{
+ return bit_posn_valid(trig->bit, field_name, clock_name);
+}
+
+/* Determine whether the set of peripheral clock registers are valid. */
+static bool
+peri_clk_data_valid(struct kona_clk *bcm_clk)
+{
+ struct peri_clk_data *peri;
+ struct bcm_clk_gate *gate;
+ struct bcm_clk_sel *sel;
+ struct bcm_clk_div *div;
+ struct bcm_clk_div *pre_div;
+ struct bcm_clk_trig *trig;
+ const char *name;
+
+ BUG_ON(bcm_clk->type != bcm_clk_peri);
+
+ /*
+ * First validate register offsets. This is the only place
+ * where we need something from the ccu, so we do these
+ * together.
+ */
+ if (!peri_clk_data_offsets_valid(bcm_clk))
+ return false;
+
+ peri = bcm_clk->peri;
+ name = bcm_clk->name;
+ gate = &peri->gate;
+ if (gate_exists(gate) && !gate_valid(gate, "gate", name))
+ return false;
+
+ sel = &peri->sel;
+ if (selector_exists(sel)) {
+ if (!sel_valid(sel, "selector", name))
+ return false;
+
+ } else if (sel->parent_count > 1) {
+ pr_err("%s: multiple parents but no selector for %s\n",
+ __func__, name);
+
+ return false;
+ }
+
+ div = &peri->div;
+ pre_div = &peri->pre_div;
+ if (divider_exists(div)) {
+ if (!div_valid(div, "divider", name))
+ return false;
+
+ if (divider_exists(pre_div))
+ if (!div_valid(pre_div, "pre-divider", name))
+ return false;
+ } else if (divider_exists(pre_div)) {
+ pr_err("%s: pre-divider but no divider for %s\n", __func__,
+ name);
+ return false;
+ }
+
+ trig = &peri->trig;
+ if (trigger_exists(trig)) {
+ if (!trig_valid(trig, "trigger", name))
+ return false;
+
+ if (trigger_exists(&peri->pre_trig)) {
+ if (!trig_valid(trig, "pre-trigger", name)) {
+ return false;
+ }
+ }
+ if (!clk_requires_trigger(bcm_clk)) {
+ pr_warn("%s: ignoring trigger for %s (not needed)\n",
+ __func__, name);
+ trigger_clear_exists(trig);
+ }
+ } else if (trigger_exists(&peri->pre_trig)) {
+ pr_err("%s: pre-trigger but no trigger for %s\n", __func__,
+ name);
+ return false;
+ } else if (clk_requires_trigger(bcm_clk)) {
+ pr_err("%s: required trigger missing for %s\n", __func__,
+ name);
+ return false;
+ }
+
+ return kona_dividers_valid(bcm_clk);
+}
+
+static bool kona_clk_valid(struct kona_clk *bcm_clk)
+{
+ switch (bcm_clk->type) {
+ case bcm_clk_peri:
+ if (!peri_clk_data_valid(bcm_clk))
+ return false;
+ break;
+ default:
+ pr_err("%s: unrecognized clock type (%d)\n", __func__,
+ (int)bcm_clk->type);
+ return false;
+ }
+ return true;
+}
+
+/*
+ * Scan an array of parent clock names to determine whether there
+ * are any entries containing BAD_CLK_NAME. Such entries are
+ * placeholders for non-supported clocks. Keep track of the
+ * position of each clock name in the original array.
+ *
+ * Allocates an array of pointers to to hold the names of all
+ * non-null entries in the original array, and returns a pointer to
+ * that array in *names. This will be used for registering the
+ * clock with the common clock code. On successful return,
+ * *count indicates how many entries are in that names array.
+ *
+ * If there is more than one entry in the resulting names array,
+ * another array is allocated to record the parent selector value
+ * for each (defined) parent clock. This is the value that
+ * represents this parent clock in the clock's source selector
+ * register. The position of the clock in the original parent array
+ * defines that selector value. The number of entries in this array
+ * is the same as the number of entries in the parent names array.
+ *
+ * The array of selector values is returned. If the clock has no
+ * parents, no selector is required and a null pointer is returned.
+ *
+ * Returns a null pointer if the clock names array supplied was
+ * null. (This is not an error.)
+ *
+ * Returns a pointer-coded error if an error occurs.
+ */
+static u32 *parent_process(const char *clocks[],
+ u32 *count, const char ***names)
+{
+ static const char **parent_names;
+ static u32 *parent_sel;
+ const char **clock;
+ u32 parent_count;
+ u32 bad_count = 0;
+ u32 orig_count;
+ u32 i;
+ u32 j;
+
+ *count = 0; /* In case of early return */
+ *names = NULL;
+ if (!clocks)
+ return NULL;
+
+ /*
+ * Count the number of names in the null-terminated array,
+ * and find out how many of those are actually clock names.
+ */
+ for (clock = clocks; *clock; clock++)
+ if (*clock == BAD_CLK_NAME)
+ bad_count++;
+ orig_count = (u32)(clock - clocks);
+ parent_count = orig_count - bad_count;
+
+ /* If all clocks are unsupported, we treat it as no clock */
+ if (!parent_count)
+ return NULL;
+
+ /* Avoid exceeding our parent clock limit */
+ if (parent_count > PARENT_COUNT_MAX) {
+ pr_err("%s: too many parents (%u > %u)\n", __func__,
+ parent_count, PARENT_COUNT_MAX);
+ return ERR_PTR(-EINVAL);
+ }
+
+ /*
+ * There is one parent name for each defined parent clock.
+ * We also maintain an array containing the selector value
+ * for each defined clock. If there's only one clock, the
+ * selector is not required, but we allocate space for the
+ * array anyway to keep things simple.
+ */
+ parent_names = kmalloc(parent_count * sizeof(parent_names), GFP_KERNEL);
+ if (!parent_names) {
+ pr_err("%s: error allocating %u parent names\n", __func__,
+ parent_count);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ /* There is at least one parent, so allocate a selector array */
+
+ parent_sel = kmalloc(parent_count * sizeof(*parent_sel), GFP_KERNEL);
+ if (!parent_sel) {
+ pr_err("%s: error allocating %u parent selectors\n", __func__,
+ parent_count);
+ kfree(parent_names);
+
+ return ERR_PTR(-ENOMEM);
+ }
+
+ /* Now fill in the parent names and selector arrays */
+ for (i = 0, j = 0; i < orig_count; i++) {
+ if (clocks[i] != BAD_CLK_NAME) {
+ parent_names[j] = clocks[i];
+ parent_sel[j] = i;
+ j++;
+ }
+ }
+ *names = parent_names;
+ *count = parent_count;
+
+ return parent_sel;
+}
+
+static int
+clk_sel_setup(const char **clocks, struct bcm_clk_sel *sel,
+ struct clk_init_data *init_data)
+{
+ const char **parent_names = NULL;
+ u32 parent_count = 0;
+ u32 *parent_sel;
+
+ /*
+ * If a peripheral clock has multiple parents, the value
+ * used by the hardware to select that parent is represented
+ * by the parent clock's position in the "clocks" list. Some
+ * values don't have defined or supported clocks; these will
+ * have BAD_CLK_NAME entries in the parents[] array. The
+ * list is terminated by a NULL entry.
+ *
+ * We need to supply (only) the names of defined parent
+ * clocks when registering a clock though, so we use an
+ * array of parent selector values to map between the
+ * indexes the common clock code uses and the selector
+ * values we need.
+ */
+ parent_sel = parent_process(clocks, &parent_count, &parent_names);
+ if (IS_ERR(parent_sel)) {
+ int ret = PTR_ERR(parent_sel);
+
+ pr_err("%s: error processing parent clocks for %s (%d)\n",
+ __func__, init_data->name, ret);
+
+ return ret;
+ }
+
+ init_data->parent_names = parent_names;
+ init_data->num_parents = parent_count;
+
+ sel->parent_count = parent_count;
+ sel->parent_sel = parent_sel;
+
+ return 0;
+}
+
+static void clk_sel_teardown(struct bcm_clk_sel *sel,
+ struct clk_init_data *init_data)
+{
+ kfree(sel->parent_sel);
+ sel->parent_sel = NULL;
+ sel->parent_count = 0;
+
+ init_data->num_parents = 0;
+ kfree(init_data->parent_names);
+ init_data->parent_names = NULL;
+}
+
+static void peri_clk_teardown(struct peri_clk_data *data,
+ struct clk_init_data *init_data)
+{
+ clk_sel_teardown(&data->sel, init_data);
+ init_data->ops = NULL;
+}
+
+/*
+ * Caller is responsible for freeing the parent_names[] and
+ * parent_sel[] arrays in the peripheral clock's "data" structure
+ * that can be assigned if the clock has one or more parent clocks
+ * associated with it.
+ */
+static int peri_clk_setup(struct ccu_data *ccu, struct peri_clk_data *data,
+ struct clk_init_data *init_data)
+{
+ init_data->ops = &kona_peri_clk_ops;
+ init_data->flags = CLK_IGNORE_UNUSED;
+
+ return clk_sel_setup(data->clocks, &data->sel, init_data);
+}
+
+static void bcm_clk_teardown(struct kona_clk *bcm_clk)
+{
+ switch (bcm_clk->type) {
+ case bcm_clk_peri:
+ peri_clk_teardown(bcm_clk->data, &bcm_clk->init_data);
+ break;
+ default:
+ break;
+ }
+ bcm_clk->data = NULL;
+ bcm_clk->type = bcm_clk_none;
+}
+
+static void kona_clk_teardown(struct clk *clk)
+{
+ struct clk_hw *hw;
+ struct kona_clk *bcm_clk;
+
+ if (!clk)
+ return;
+
+ hw = __clk_get_hw(clk);
+ if (!hw) {
+ pr_err("%s: clk %p has null hw pointer\n", __func__, clk);
+ return;
+ }
+ clk_unregister(clk);
+
+ bcm_clk = to_kona_clk(hw);
+ bcm_clk_teardown(bcm_clk);
+}
+
+struct clk *kona_clk_setup(struct ccu_data *ccu, const char *name,
+ enum bcm_clk_type type, void *data)
+{
+ struct kona_clk *bcm_clk;
+ struct clk_init_data *init_data;
+ struct clk *clk = NULL;
+
+ bcm_clk = kzalloc(sizeof(*bcm_clk), GFP_KERNEL);
+ if (!bcm_clk) {
+ pr_err("%s: failed to allocate bcm_clk for %s\n", __func__,
+ name);
+ return NULL;
+ }
+ bcm_clk->ccu = ccu;
+ bcm_clk->name = name;
+
+ init_data = &bcm_clk->init_data;
+ init_data->name = name;
+ switch (type) {
+ case bcm_clk_peri:
+ if (peri_clk_setup(ccu, data, init_data))
+ goto out_free;
+ break;
+ default:
+ data = NULL;
+ break;
+ }
+ bcm_clk->type = type;
+ bcm_clk->data = data;
+
+ /* Make sure everything makes sense before we set it up */
+ if (!kona_clk_valid(bcm_clk)) {
+ pr_err("%s: clock data invalid for %s\n", __func__, name);
+ goto out_teardown;
+ }
+
+ bcm_clk->hw.init = init_data;
+ clk = clk_register(NULL, &bcm_clk->hw);
+ if (IS_ERR(clk)) {
+ pr_err("%s: error registering clock %s (%ld)\n", __func__,
+ name, PTR_ERR(clk));
+ goto out_teardown;
+ }
+ BUG_ON(!clk);
+
+ return clk;
+out_teardown:
+ bcm_clk_teardown(bcm_clk);
+out_free:
+ kfree(bcm_clk);
+
+ return NULL;
+}
+
+static void ccu_clks_teardown(struct ccu_data *ccu)
+{
+ u32 i;
+
+ for (i = 0; i < ccu->data.clk_num; i++)
+ kona_clk_teardown(ccu->data.clks[i]);
+ kfree(ccu->data.clks);
+}
+
+static void kona_ccu_teardown(struct ccu_data *ccu)
+{
+ if (!ccu)
+ return;
+
+ if (!ccu->base)
+ goto done;
+
+ of_clk_del_provider(ccu->node); /* safe if never added */
+ ccu_clks_teardown(ccu);
+ list_del(&ccu->links);
+ of_node_put(ccu->node);
+ iounmap(ccu->base);
+done:
+ kfree(ccu->name);
+ kfree(ccu);
+}
+
+/*
+ * Set up a CCU. Call the provided ccu_clks_setup callback to
+ * initialize the array of clocks provided by the CCU.
+ */
+void __init kona_dt_ccu_setup(struct device_node *node,
+ int (*ccu_clks_setup)(struct ccu_data *))
+{
+ struct ccu_data *ccu;
+ struct resource res = { 0 };
+ resource_size_t range;
+ int ret;
+
+ ccu = kzalloc(sizeof(*ccu), GFP_KERNEL);
+ if (ccu)
+ ccu->name = kstrdup(node->name, GFP_KERNEL);
+ if (!ccu || !ccu->name) {
+ pr_err("%s: unable to allocate CCU struct for %s\n",
+ __func__, node->name);
+ kfree(ccu);
+
+ return;
+ }
+
+ ret = of_address_to_resource(node, 0, &res);
+ if (ret) {
+ pr_err("%s: no valid CCU registers found for %s\n", __func__,
+ node->name);
+ goto out_err;
+ }
+
+ range = resource_size(&res);
+ if (range > (resource_size_t)U32_MAX) {
+ pr_err("%s: address range too large for %s\n", __func__,
+ node->name);
+ goto out_err;
+ }
+
+ ccu->range = (u32)range;
+ ccu->base = ioremap(res.start, ccu->range);
+ if (!ccu->base) {
+ pr_err("%s: unable to map CCU registers for %s\n", __func__,
+ node->name);
+ goto out_err;
+ }
+
+ spin_lock_init(&ccu->lock);
+ INIT_LIST_HEAD(&ccu->links);
+ ccu->node = of_node_get(node);
+
+ list_add_tail(&ccu->links, &ccu_list);
+
+ /* Set up clocks array (in ccu->data) */
+ if (ccu_clks_setup(ccu))
+ goto out_err;
+
+ ret = of_clk_add_provider(node, of_clk_src_onecell_get, &ccu->data);
+ if (ret) {
+ pr_err("%s: error adding ccu %s as provider (%d)\n", __func__,
+ node->name, ret);
+ goto out_err;
+ }
+
+ if (!kona_ccu_init(ccu))
+ pr_err("Broadcom %s initialization had errors\n", node->name);
+
+ return;
+out_err:
+ kona_ccu_teardown(ccu);
+ pr_err("Broadcom %s setup aborted\n", node->name);
+}