cbus clocks are virtual clocks which implement coordinated changes to clock rates. These are needed because changing a PLLs rate cannot be done with active child clocks. Therefore the child clocks are moved to a backup pll during the PLL rate change. shared clocks are virtual clocks which implement clock policies (eg min or max rates). Signed-off-by: Peter De Schrijver <pdeschrijver@xxxxxxxxxx> --- drivers/clk/Makefile | 1 + drivers/clk/clk-shared-cbus.c | 448 +++++++++++++++++++++++++++++++++++++++++ include/linux/clk-provider.h | 56 +++++ 3 files changed, 505 insertions(+), 0 deletions(-) create mode 100644 drivers/clk/clk-shared-cbus.c diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile index 5f8a287..8d9255b5 100644 --- a/drivers/clk/Makefile +++ b/drivers/clk/Makefile @@ -8,6 +8,7 @@ obj-$(CONFIG_COMMON_CLK) += clk-fixed-rate.o obj-$(CONFIG_COMMON_CLK) += clk-gate.o obj-$(CONFIG_COMMON_CLK) += clk-mux.o obj-$(CONFIG_COMMON_CLK) += clk-composite.o +obj-y += clk-shared-cbus.o # hardware specific clock types # please keep this section sorted lexicographically by file/directory path name diff --git a/drivers/clk/clk-shared-cbus.c b/drivers/clk/clk-shared-cbus.c new file mode 100644 index 0000000..402b4c3 --- /dev/null +++ b/drivers/clk/clk-shared-cbus.c @@ -0,0 +1,448 @@ +/* + * Copyright (c) 2012 - 2014, NVIDIA CORPORATION. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/slab.h> +#include <linux/io.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/clk-provider.h> +#include <linux/clk.h> + +static unsigned long _clk_cap_shared_bus(struct clk *c, unsigned long rate, + unsigned long ceiling) +{ + ceiling = clk_round_rate(c, ceiling); + + rate = min(rate, ceiling); + + return rate; +} + +static int _clk_shared_bus_update(struct clk *bus) +{ + struct clk_cbus_shared *cbus = + to_clk_cbus_shared(__clk_get_hw(bus)); + struct clk_cbus_shared *c; + unsigned long override_rate = 0; + unsigned long top_rate = 0; + unsigned long rate = cbus->min_rate; + unsigned long bw = 0; + unsigned long ceiling = cbus->max_rate; + + list_for_each_entry(c, &cbus->shared_bus_list, + u.shared_bus_user.node) { + /* + * Ignore requests from disabled floor, bw users, and + * auto-users riding the bus. Always check the ceiling users + * so we don't need to enable it for capping the bus rate. + */ + if (c->u.shared_bus_user.enabled || + (c->u.shared_bus_user.mode == SHARED_CEILING)) { + unsigned long request_rate = c->u.shared_bus_user.rate; + + switch (c->u.shared_bus_user.mode) { + case SHARED_BW: + bw += request_rate; + if (bw > cbus->max_rate) + bw = cbus->max_rate; + break; + case SHARED_CEILING: + if (request_rate) + ceiling = min(request_rate, ceiling); + break; + case SHARED_OVERRIDE: + if (override_rate == 0) + override_rate = request_rate; + break; + case SHARED_AUTO: + break; + case SHARED_FLOOR: + default: + top_rate = max(request_rate, top_rate); + rate = max(top_rate, rate); + } + } + } + /* + * Keep the bus rate as its default rate when there is no SHARED_FLOOR + * users enabled so we won't underrun the bus. + */ + if (!top_rate) + rate = clk_get_rate(bus); + rate = override_rate ? : max(rate, bw); + ceiling = override_rate ? cbus->max_rate : ceiling; + + rate = _clk_cap_shared_bus(bus, rate, ceiling); + + return clk_set_rate(bus, rate); +} + +static int clk_shared_prepare(struct clk_hw *hw) +{ + int err = 0; + struct clk_cbus_shared *shared = to_clk_cbus_shared(hw); + + shared->u.shared_bus_user.enabled = true; + err = _clk_shared_bus_update(clk_get_parent(hw->clk)); + if (!err && shared->u.shared_bus_user.client) + err = clk_prepare_enable(shared->u.shared_bus_user.client); + + return err; +} + +static void clk_shared_unprepare(struct clk_hw *hw) +{ + struct clk_cbus_shared *shared = to_clk_cbus_shared(hw); + + if (shared->u.shared_bus_user.client) + clk_disable_unprepare(shared->u.shared_bus_user.client); + + shared->u.shared_bus_user.enabled = false; + _clk_shared_bus_update(clk_get_parent(hw->clk)); +} + +static bool shared_clk_set_rate; + +static int clk_shared_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct clk_cbus_shared *shared = to_clk_cbus_shared(hw); + int err; + + if (shared_clk_set_rate) + return 0; + + shared_clk_set_rate = true; + shared->u.shared_bus_user.rate = rate; + err = _clk_shared_bus_update(clk_get_parent(hw->clk)); + shared_clk_set_rate = false; + + return err; +} + +static long clk_shared_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *parent_rate) +{ + struct clk_cbus_shared *shared = to_clk_cbus_shared(hw); + struct clk_cbus_shared *parent_cbus; + struct clk *parent; + int ret; + + parent = clk_get_parent(hw->clk); + parent_cbus = to_clk_cbus_shared(__clk_get_hw(parent)); + + /* + * Defer rounding requests until aggregated. BW users must not be + * rounded at all, others just clipped to bus range (some clients + * may use round api to find limits) + */ + if (shared->u.shared_bus_user.mode != SHARED_BW) { + if (!parent_cbus->max_rate) { + ret = clk_round_rate(parent, ULONG_MAX); + if (!IS_ERR_VALUE(ret)) + parent_cbus->max_rate = ret; + } + + if (rate > parent_cbus->max_rate) + rate = parent_cbus->max_rate; + else if (rate < parent_cbus->min_rate) + rate = parent_cbus->min_rate; + } + return rate; +} + +static unsigned long clk_shared_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct clk_cbus_shared *shared = to_clk_cbus_shared(hw); + + return shared->u.shared_bus_user.rate; +} + +static int cbus_switch_one(struct clk *client, struct clk *p) +{ + int ret = 0; + unsigned long old_parent_rate, new_parent_rate, current_rate; + + current_rate = clk_get_rate(client); + old_parent_rate = clk_get_rate(clk_get_parent(client)); + new_parent_rate = clk_get_rate(p); + + if (new_parent_rate > old_parent_rate) { + u64 temp_rate; + + /* + * In order to not overclocking the IP block when changing the + * parent, we set the divider to a value which will give us an + * allowed rate when the new parent is selected. + */ + temp_rate = DIV_ROUND_UP_ULL((u64)clk_get_rate(client) * + (u64)old_parent_rate, new_parent_rate); + ret = clk_set_rate(client, temp_rate); + if (ret) { + pr_err("failed to set %s rate to %llu: %d\n", + __clk_get_name(client), temp_rate, ret); + return ret; + } + } + + ret = clk_set_parent(client, p); + if (ret) { + pr_err("failed to set %s parent to %s: %d\n", + __clk_get_name(client), + __clk_get_name(p), ret); + return ret; + } + + clk_set_rate(client, current_rate); + + return ret; +} + +static int cbus_backup(struct clk_hw *hw) +{ + int ret = 0; + struct clk_cbus_shared *cbus = to_clk_cbus_shared(hw); + struct clk_cbus_shared *user; + + list_for_each_entry(user, &cbus->shared_bus_list, + u.shared_bus_user.node) { + struct clk *client = user->u.shared_bus_user.client; + + if (client && __clk_is_enabled(client) && + (clk_get_parent(client) == clk_get_parent(hw->clk))) { + ret = cbus_switch_one(client, cbus->shared_bus_backup); + if (ret) + break; + } + } + + return ret; +} + +static void cbus_restore(struct clk_hw *hw) +{ + struct clk_cbus_shared *user; + struct clk_cbus_shared *cbus = to_clk_cbus_shared(hw); + + list_for_each_entry(user, &cbus->shared_bus_list, + u.shared_bus_user.node) { + struct clk *client = user->u.shared_bus_user.client; + + if (client) { + cbus_switch_one(client, clk_get_parent(hw->clk)); + clk_set_rate(client, user->u.shared_bus_user.rate); + } + } +} + +static int clk_cbus_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + int ret; + struct clk *parent; + struct clk_cbus_shared *cbus = to_clk_cbus_shared(hw); + + if (cbus->rate_updating) + return 0; + + if (rate == 0) + return 0; + + cbus->rate_updating = true; + + parent = clk_get_parent(hw->clk); + if (!parent) { + cbus->rate_updating = false; + return -EINVAL; + } + + ret = clk_prepare_enable(parent); + if (ret) { + cbus->rate_updating = false; + pr_err("%s: failed to enable %s clock: %d\n", + __func__, __clk_get_name(hw->clk), ret); + return ret; + } + + ret = cbus_backup(hw); + if (ret) + goto out; + + ret = clk_set_rate(parent, rate); + if (ret) { + pr_err("%s: failed to set %s clock rate %lu: %d\n", + __func__, __clk_get_name(hw->clk), rate, ret); + goto out; + } + + cbus_restore(hw); + +out: + cbus->rate_updating = false; + clk_disable_unprepare(parent); + return ret; +} + +static long clk_cbus_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *parent_rate) +{ + struct clk *parent; + long new_rate; + + parent = clk_get_parent(hw->clk); + if (IS_ERR(parent)) { + pr_err("no parent for %s\n", __clk_get_name(hw->clk)); + return *parent_rate; + } else { + new_rate = clk_round_rate(parent, rate); + if (new_rate < 0) + return *parent_rate; + else + return new_rate; + } +} + +static unsigned long clk_cbus_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + return clk_get_rate(clk_get_parent(hw->clk)); +} + +static const struct clk_ops clk_shared_ops = { + .prepare = clk_shared_prepare, + .unprepare = clk_shared_unprepare, + .set_rate = clk_shared_set_rate, + .round_rate = clk_shared_round_rate, + .recalc_rate = clk_shared_recalc_rate, +}; + +static const struct clk_ops tegra_clk_cbus_ops = { + .recalc_rate = clk_cbus_recalc_rate, + .round_rate = clk_cbus_round_rate, + .set_rate = clk_cbus_set_rate, +}; + +struct clk *clk_register_shared(const char *name, + const char **parent, u8 num_parents, unsigned long flags, + enum shared_bus_users_mode mode, const char *client) +{ + struct clk_cbus_shared *shared; + struct clk_init_data init; + struct clk_cbus_shared *parent_cbus; + struct clk *client_clk, *parent_clk; + +pr_err("%s:%d name: %s\n", __FILE__, __LINE__, name); + + if (num_parents > 2) + return ERR_PTR(-EINVAL); + + parent_clk = __clk_lookup(parent[0]); + if (IS_ERR(parent_clk)) + return parent_clk; + + parent_cbus = to_clk_cbus_shared(__clk_get_hw(parent_clk)); + + shared = kzalloc(sizeof(*shared), GFP_KERNEL); + if (!shared) + return ERR_PTR(-ENOMEM); + + if (client) { + client_clk = __clk_lookup(client); + if (IS_ERR(client_clk)) { + kfree(shared); + return client_clk; + } + shared->u.shared_bus_user.client = client_clk; + shared->magic = CLK_SHARED_MAGIC; + } + + shared->u.shared_bus_user.mode = mode; + if (mode == SHARED_CEILING) + shared->u.shared_bus_user.rate = parent_cbus->max_rate; + else + shared->u.shared_bus_user.rate = clk_get_rate(parent_clk); + + shared->flags = flags; + + if (num_parents > 1) { + struct clk *c = __clk_lookup(parent[1]); + + if (!IS_ERR(c)) { + shared->u.shared_bus_user.inputs[0] = parent_clk; + shared->u.shared_bus_user.inputs[1] = c; + } + } + shared->max_rate = parent_cbus->max_rate; + + INIT_LIST_HEAD(&shared->u.shared_bus_user.node); + + list_add_tail(&shared->u.shared_bus_user.node, + &parent_cbus->shared_bus_list); + + flags |= CLK_GET_RATE_NOCACHE; + + init.name = name; + init.ops = &clk_shared_ops; + init.flags = flags; + init.parent_names = parent; + init.num_parents = 1; + + /* Data in .init is copied by clk_register(), so stack variable OK */ + shared->hw.init = &init; + + return clk_register(NULL, &shared->hw); +} + +struct clk *clk_register_cbus(const char *name, + const char *parent, unsigned long flags, + const char *backup, unsigned long min_rate, + unsigned long max_rate) +{ + struct clk_cbus_shared *cbus; + struct clk_init_data init; + struct clk *backup_clk; + + cbus = kzalloc(sizeof(*cbus), GFP_KERNEL); + if (!cbus) + return ERR_PTR(-ENOMEM); + + backup_clk = __clk_lookup(backup); + if (IS_ERR(backup_clk)) { + kfree(cbus); + return backup_clk; + } + + cbus->shared_bus_backup = backup_clk; + cbus->min_rate = min_rate; + cbus->max_rate = max_rate; + + INIT_LIST_HEAD(&cbus->shared_bus_list); + + flags |= CLK_GET_RATE_NOCACHE; + + init.name = name; + init.ops = &tegra_clk_cbus_ops; + init.flags = flags; + init.parent_names = &parent; + init.num_parents = 1; + + /* Data in .init is copied by clk_register(), so stack variable OK */ + cbus->hw.init = &init; + + return clk_register(NULL, &cbus->hw); +} + diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index 5119174..0fd195d 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -444,6 +444,62 @@ struct clk *clk_register_composite(struct device *dev, const char *name, struct clk_hw *gate_hw, const struct clk_ops *gate_ops, unsigned long flags); +enum shared_bus_users_mode { + SHARED_FLOOR = 0, + SHARED_BW, + SHARED_CEILING, + SHARED_AUTO, + SHARED_OVERRIDE, +}; + +#define CLK_SHARED_MAGIC 0x18ce213d + +struct clk_cbus_shared { + u32 magic; + struct clk_hw hw; + struct list_head shared_bus_list; + struct clk *shared_bus_backup; + u32 flags; + unsigned long min_rate; + unsigned long max_rate; + bool rate_updating; + bool prepared; + union { + struct { + struct clk_hw *top_user; + struct clk_hw *slow_user; + } cbus; + struct { + struct clk_hw *pclk; + struct clk_hw *hclk; + struct clk_hw *sclk_low; + struct clk_hw *sclk_high; + unsigned long threshold; + } system; + struct { + struct list_head node; + bool enabled; + unsigned long rate; + struct clk *client; + u32 client_div; + enum shared_bus_users_mode mode; + struct clk *inputs[2]; + } shared_bus_user; + } u; +}; + +#define to_clk_cbus_shared(_hw) \ + container_of(_hw, struct clk_cbus_shared, hw) + +struct clk *clk_register_shared(const char *name, + const char **parent, u8 num_parents, unsigned long flags, + enum shared_bus_users_mode mode, const char *client); + +struct clk *clk_register_cbus(const char *name, + const char *parent, unsigned long flags, + const char *backup, unsigned long min_rate, + unsigned long max_rate); + /** * clk_register - allocate a new clock, register it and return an opaque cookie * @dev: device that is registering this clock -- 1.7.7.rc0.72.g4b5ea.dirty -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
