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331 lines
8.1 KiB
331 lines
8.1 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved. |
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* Copyright (C) 2018-2021 Linaro Ltd. |
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*/ |
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#include <linux/refcount.h> |
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#include <linux/mutex.h> |
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#include <linux/clk.h> |
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#include <linux/device.h> |
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#include <linux/interconnect.h> |
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#include "ipa.h" |
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#include "ipa_clock.h" |
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#include "ipa_modem.h" |
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#include "ipa_data.h" |
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/** |
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* DOC: IPA Clocking |
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* |
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* The "IPA Clock" manages both the IPA core clock and the interconnects |
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* (buses) the IPA depends on as a single logical entity. A reference count |
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* is incremented by "get" operations and decremented by "put" operations. |
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* Transitions of that count from 0 to 1 result in the clock and interconnects |
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* being enabled, and transitions of the count from 1 to 0 cause them to be |
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* disabled. We currently operate the core clock at a fixed clock rate, and |
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* all buses at a fixed average and peak bandwidth. As more advanced IPA |
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* features are enabled, we can make better use of clock and bus scaling. |
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* |
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* An IPA clock reference must be held for any access to IPA hardware. |
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*/ |
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/** |
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* struct ipa_interconnect - IPA interconnect information |
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* @path: Interconnect path |
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* @average_bandwidth: Average interconnect bandwidth (KB/second) |
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* @peak_bandwidth: Peak interconnect bandwidth (KB/second) |
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*/ |
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struct ipa_interconnect { |
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struct icc_path *path; |
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u32 average_bandwidth; |
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u32 peak_bandwidth; |
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}; |
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/** |
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* struct ipa_clock - IPA clocking information |
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* @count: Clocking reference count |
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* @mutex: Protects clock enable/disable |
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* @core: IPA core clock |
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* @interconnect_count: Number of elements in interconnect[] |
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* @interconnect: Interconnect array |
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*/ |
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struct ipa_clock { |
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refcount_t count; |
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struct mutex mutex; /* protects clock enable/disable */ |
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struct clk *core; |
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u32 interconnect_count; |
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struct ipa_interconnect *interconnect; |
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}; |
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static int ipa_interconnect_init_one(struct device *dev, |
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struct ipa_interconnect *interconnect, |
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const struct ipa_interconnect_data *data) |
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{ |
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struct icc_path *path; |
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path = of_icc_get(dev, data->name); |
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if (IS_ERR(path)) { |
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int ret = PTR_ERR(path); |
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dev_err_probe(dev, ret, "error getting %s interconnect\n", |
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data->name); |
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return ret; |
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} |
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interconnect->path = path; |
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interconnect->average_bandwidth = data->average_bandwidth; |
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interconnect->peak_bandwidth = data->peak_bandwidth; |
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return 0; |
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} |
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static void ipa_interconnect_exit_one(struct ipa_interconnect *interconnect) |
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{ |
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icc_put(interconnect->path); |
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memset(interconnect, 0, sizeof(*interconnect)); |
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} |
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/* Initialize interconnects required for IPA operation */ |
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static int ipa_interconnect_init(struct ipa_clock *clock, struct device *dev, |
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const struct ipa_interconnect_data *data) |
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{ |
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struct ipa_interconnect *interconnect; |
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u32 count; |
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int ret; |
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count = clock->interconnect_count; |
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interconnect = kcalloc(count, sizeof(*interconnect), GFP_KERNEL); |
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if (!interconnect) |
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return -ENOMEM; |
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clock->interconnect = interconnect; |
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while (count--) { |
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ret = ipa_interconnect_init_one(dev, interconnect, data++); |
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if (ret) |
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goto out_unwind; |
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interconnect++; |
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} |
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return 0; |
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out_unwind: |
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while (interconnect-- > clock->interconnect) |
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ipa_interconnect_exit_one(interconnect); |
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kfree(clock->interconnect); |
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clock->interconnect = NULL; |
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return ret; |
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} |
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/* Inverse of ipa_interconnect_init() */ |
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static void ipa_interconnect_exit(struct ipa_clock *clock) |
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{ |
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struct ipa_interconnect *interconnect; |
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interconnect = clock->interconnect + clock->interconnect_count; |
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while (interconnect-- > clock->interconnect) |
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ipa_interconnect_exit_one(interconnect); |
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kfree(clock->interconnect); |
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clock->interconnect = NULL; |
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} |
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/* Currently we only use one bandwidth level, so just "enable" interconnects */ |
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static int ipa_interconnect_enable(struct ipa *ipa) |
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{ |
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struct ipa_interconnect *interconnect; |
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struct ipa_clock *clock = ipa->clock; |
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int ret; |
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u32 i; |
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interconnect = clock->interconnect; |
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for (i = 0; i < clock->interconnect_count; i++) { |
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ret = icc_set_bw(interconnect->path, |
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interconnect->average_bandwidth, |
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interconnect->peak_bandwidth); |
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if (ret) |
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goto out_unwind; |
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interconnect++; |
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} |
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return 0; |
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out_unwind: |
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while (interconnect-- > clock->interconnect) |
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(void)icc_set_bw(interconnect->path, 0, 0); |
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return ret; |
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} |
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/* To disable an interconnect, we just its bandwidth to 0 */ |
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static void ipa_interconnect_disable(struct ipa *ipa) |
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{ |
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struct ipa_interconnect *interconnect; |
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struct ipa_clock *clock = ipa->clock; |
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int result = 0; |
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u32 count; |
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int ret; |
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count = clock->interconnect_count; |
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interconnect = clock->interconnect + count; |
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while (count--) { |
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interconnect--; |
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ret = icc_set_bw(interconnect->path, 0, 0); |
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if (ret && !result) |
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result = ret; |
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} |
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if (result) |
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dev_err(&ipa->pdev->dev, |
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"error %d disabling IPA interconnects\n", ret); |
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} |
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/* Turn on IPA clocks, including interconnects */ |
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static int ipa_clock_enable(struct ipa *ipa) |
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{ |
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int ret; |
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ret = ipa_interconnect_enable(ipa); |
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if (ret) |
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return ret; |
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ret = clk_prepare_enable(ipa->clock->core); |
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if (ret) |
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ipa_interconnect_disable(ipa); |
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return ret; |
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} |
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/* Inverse of ipa_clock_enable() */ |
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static void ipa_clock_disable(struct ipa *ipa) |
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{ |
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clk_disable_unprepare(ipa->clock->core); |
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ipa_interconnect_disable(ipa); |
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} |
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/* Get an IPA clock reference, but only if the reference count is |
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* already non-zero. Returns true if the additional reference was |
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* added successfully, or false otherwise. |
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*/ |
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bool ipa_clock_get_additional(struct ipa *ipa) |
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{ |
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return refcount_inc_not_zero(&ipa->clock->count); |
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} |
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/* Get an IPA clock reference. If the reference count is non-zero, it is |
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* incremented and return is immediate. Otherwise it is checked again |
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* under protection of the mutex, and if appropriate the IPA clock |
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* is enabled. |
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* |
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* Incrementing the reference count is intentionally deferred until |
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* after the clock is running and endpoints are resumed. |
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*/ |
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void ipa_clock_get(struct ipa *ipa) |
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{ |
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struct ipa_clock *clock = ipa->clock; |
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int ret; |
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/* If the clock is running, just bump the reference count */ |
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if (ipa_clock_get_additional(ipa)) |
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return; |
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/* Otherwise get the mutex and check again */ |
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mutex_lock(&clock->mutex); |
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/* A reference might have been added before we got the mutex. */ |
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if (ipa_clock_get_additional(ipa)) |
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goto out_mutex_unlock; |
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ret = ipa_clock_enable(ipa); |
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if (ret) { |
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dev_err(&ipa->pdev->dev, "error %d enabling IPA clock\n", ret); |
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goto out_mutex_unlock; |
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} |
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refcount_set(&clock->count, 1); |
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out_mutex_unlock: |
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mutex_unlock(&clock->mutex); |
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} |
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/* Attempt to remove an IPA clock reference. If this represents the |
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* last reference, disable the IPA clock under protection of the mutex. |
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*/ |
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void ipa_clock_put(struct ipa *ipa) |
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{ |
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struct ipa_clock *clock = ipa->clock; |
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/* If this is not the last reference there's nothing more to do */ |
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if (!refcount_dec_and_mutex_lock(&clock->count, &clock->mutex)) |
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return; |
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ipa_clock_disable(ipa); |
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mutex_unlock(&clock->mutex); |
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} |
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/* Return the current IPA core clock rate */ |
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u32 ipa_clock_rate(struct ipa *ipa) |
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{ |
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return ipa->clock ? (u32)clk_get_rate(ipa->clock->core) : 0; |
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} |
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/* Initialize IPA clocking */ |
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struct ipa_clock * |
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ipa_clock_init(struct device *dev, const struct ipa_clock_data *data) |
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{ |
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struct ipa_clock *clock; |
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struct clk *clk; |
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int ret; |
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clk = clk_get(dev, "core"); |
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if (IS_ERR(clk)) { |
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dev_err_probe(dev, PTR_ERR(clk), "error getting core clock\n"); |
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return ERR_CAST(clk); |
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} |
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ret = clk_set_rate(clk, data->core_clock_rate); |
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if (ret) { |
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dev_err(dev, "error %d setting core clock rate to %u\n", |
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ret, data->core_clock_rate); |
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goto err_clk_put; |
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} |
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clock = kzalloc(sizeof(*clock), GFP_KERNEL); |
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if (!clock) { |
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ret = -ENOMEM; |
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goto err_clk_put; |
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} |
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clock->core = clk; |
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clock->interconnect_count = data->interconnect_count; |
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ret = ipa_interconnect_init(clock, dev, data->interconnect_data); |
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if (ret) |
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goto err_kfree; |
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mutex_init(&clock->mutex); |
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refcount_set(&clock->count, 0); |
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return clock; |
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err_kfree: |
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kfree(clock); |
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err_clk_put: |
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clk_put(clk); |
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return ERR_PTR(ret); |
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} |
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/* Inverse of ipa_clock_init() */ |
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void ipa_clock_exit(struct ipa_clock *clock) |
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{ |
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struct clk *clk = clock->core; |
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WARN_ON(refcount_read(&clock->count) != 0); |
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mutex_destroy(&clock->mutex); |
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ipa_interconnect_exit(clock); |
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kfree(clock); |
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clk_put(clk); |
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}
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