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![Sameer Pujar](/assets/img/avatar_default.png)
gic-pm driver is using pm-clk framework to manage clock resources, where clocks remain always ON. This happens on Tegra devices which use BPMP co-processor to manage the clocks. Calls to BPMP are always blocking and hence it is necessary to enable/disable clocks during prepare/unprepare phase respectively. When pm-clk is used, prepare count of clock is not balanced until pm_clk_remove() happens. Clock is prepared in the driver probe() and thus prepare count of clock remains non-zero, which in turn keeps clock ON always. Please note that above mentioned behavior is specific to Tegra devices using BPMP for clock management and this should not be seen on other devices. Though this patch uses clk_bulk APIs to address the mentioned behavior, this works fine for all devices. To simplify gic_get_clocks() API is removed and instead probe can do necessary setup. Suggested-by: Mohan Kumar D <mkumard@nvidia.com> Signed-off-by: Sameer Pujar <spujar@nvidia.com> Reviewed-by: Jon Hunter <jonathanh@nvidia.com> Tested-by: Jon Hunter <jonathanh@nvidia.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
171 lines
4 KiB
C
171 lines
4 KiB
C
/*
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* Copyright (C) 2016 NVIDIA CORPORATION, All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/module.h>
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#include <linux/clk.h>
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#include <linux/of_device.h>
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#include <linux/of_irq.h>
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#include <linux/irqchip/arm-gic.h>
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#include <linux/platform_device.h>
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#include <linux/pm_runtime.h>
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#include <linux/slab.h>
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struct gic_clk_data {
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unsigned int num_clocks;
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const char *const *clocks;
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};
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struct gic_chip_pm {
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struct gic_chip_data *chip_data;
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const struct gic_clk_data *clk_data;
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struct clk_bulk_data *clks;
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};
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static int gic_runtime_resume(struct device *dev)
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{
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struct gic_chip_pm *chip_pm = dev_get_drvdata(dev);
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struct gic_chip_data *gic = chip_pm->chip_data;
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const struct gic_clk_data *data = chip_pm->clk_data;
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int ret;
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ret = clk_bulk_prepare_enable(data->num_clocks, chip_pm->clks);
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if (ret) {
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dev_err(dev, "clk_enable failed: %d\n", ret);
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return ret;
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}
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/*
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* On the very first resume, the pointer to chip_pm->chip_data
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* will be NULL and this is intentional, because we do not
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* want to restore the GIC on the very first resume. So if
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* the pointer is not valid just return.
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*/
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if (!gic)
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return 0;
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gic_dist_restore(gic);
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gic_cpu_restore(gic);
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return 0;
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}
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static int gic_runtime_suspend(struct device *dev)
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{
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struct gic_chip_pm *chip_pm = dev_get_drvdata(dev);
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struct gic_chip_data *gic = chip_pm->chip_data;
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const struct gic_clk_data *data = chip_pm->clk_data;
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gic_dist_save(gic);
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gic_cpu_save(gic);
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clk_bulk_disable_unprepare(data->num_clocks, chip_pm->clks);
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return 0;
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}
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static int gic_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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const struct gic_clk_data *data;
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struct gic_chip_pm *chip_pm;
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int ret, irq, i;
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data = of_device_get_match_data(&pdev->dev);
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if (!data) {
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dev_err(&pdev->dev, "no device match found\n");
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return -ENODEV;
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}
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chip_pm = devm_kzalloc(dev, sizeof(*chip_pm), GFP_KERNEL);
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if (!chip_pm)
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return -ENOMEM;
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irq = irq_of_parse_and_map(dev->of_node, 0);
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if (!irq) {
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dev_err(dev, "no parent interrupt found!\n");
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return -EINVAL;
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}
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chip_pm->clks = devm_kcalloc(dev, data->num_clocks,
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sizeof(*chip_pm->clks), GFP_KERNEL);
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if (!chip_pm->clks)
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return -ENOMEM;
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for (i = 0; i < data->num_clocks; i++)
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chip_pm->clks[i].id = data->clocks[i];
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ret = devm_clk_bulk_get(dev, data->num_clocks, chip_pm->clks);
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if (ret)
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goto irq_dispose;
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chip_pm->clk_data = data;
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dev_set_drvdata(dev, chip_pm);
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pm_runtime_enable(dev);
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ret = pm_runtime_get_sync(dev);
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if (ret < 0)
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goto rpm_disable;
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ret = gic_of_init_child(dev, &chip_pm->chip_data, irq);
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if (ret)
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goto rpm_put;
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pm_runtime_put(dev);
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dev_info(dev, "GIC IRQ controller registered\n");
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return 0;
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rpm_put:
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pm_runtime_put_sync(dev);
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rpm_disable:
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pm_runtime_disable(dev);
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irq_dispose:
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irq_dispose_mapping(irq);
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return ret;
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}
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static const struct dev_pm_ops gic_pm_ops = {
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SET_RUNTIME_PM_OPS(gic_runtime_suspend,
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gic_runtime_resume, NULL)
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};
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static const char * const gic400_clocks[] = {
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"clk",
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};
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static const struct gic_clk_data gic400_data = {
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.num_clocks = ARRAY_SIZE(gic400_clocks),
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.clocks = gic400_clocks,
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};
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static const struct of_device_id gic_match[] = {
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{ .compatible = "nvidia,tegra210-agic", .data = &gic400_data },
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{},
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};
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MODULE_DEVICE_TABLE(of, gic_match);
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static struct platform_driver gic_driver = {
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.probe = gic_probe,
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.driver = {
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.name = "gic",
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.of_match_table = gic_match,
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.pm = &gic_pm_ops,
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}
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};
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builtin_platform_driver(gic_driver);
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