github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-05-28 09:04:39 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

spi: tegra210-quad: Add runtime autosuspend support

Browse Source 
Using Tegra234, it was found that it takes about 10us to disable clocks
and 20us to enable clocks, adding about 30us overhead per operation.
For a 4MB firmware update with 16,384 page programs, this results in
~491ms total overhead (12% impact).

With Tegra234, flash operations were observed to occur in bursts with
50-200μs gaps between page programs. Testing on Tegra234 with various
operation patterns shows 500ms delay provides optimal balance, and for
longer operations (>500ms), the overhead is negligible. Therefore,
update the driver to use pm-runtime autosuspend with the default timeout
of 500ms to reduce the clock gating overhead during consecutive QSPI
transfers.

Signed-off-by: Vishwaroop A <va@nvidia.com>
Link: https://patch.msgid.link/20260224092452.1482800-1-va@nvidia.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Vishwaroop A 2026-02-24 09:24:52 +00:00 committed by Mark Brown
parent 507a071d98
commit 7c12f6ead4
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
1 changed files with 16 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
drivers/spi/spi-tegra210-quad.c
View File

@ -1000,7 +1000,8 @@ static int tegra_qspi_setup(struct spi_device *spi)
spin_unlock_irqrestore(&tqspi->lock, flags);
pm_runtime_put(tqspi->dev);
pm_runtime_mark_last_busy(tqspi->dev);
pm_runtime_put_autosuspend(tqspi->dev);
return 0;
}
@ -1765,6 +1766,14 @@ static int tegra_qspi_probe(struct platform_device *pdev)
init_completion(&tqspi->rx_dma_complete);
init_completion(&tqspi->xfer_completion);
/*
* Set autosuspend delay to 500ms. Testing shows this value eliminates
* suspend/resume overhead during burst operations while allowing quick
* suspension during idle. For longer operations, the overhead is negligible.
*/
pm_runtime_set_autosuspend_delay(&pdev->dev, 500);
pm_runtime_use_autosuspend(&pdev->dev);
pm_runtime_enable(&pdev->dev);
ret = pm_runtime_resume_and_get(&pdev->dev);
if (ret < 0) {
@ -1781,7 +1790,8 @@ static int tegra_qspi_probe(struct platform_device *pdev)
tqspi->spi_cs_timing2 = tegra_qspi_readl(tqspi, QSPI_CS_TIMING2);
tqspi->def_command2_reg = tegra_qspi_readl(tqspi, QSPI_COMMAND2);
pm_runtime_put(&pdev->dev);
pm_runtime_mark_last_busy(&pdev->dev);
pm_runtime_put_autosuspend(&pdev->dev);
ret = request_threaded_irq(tqspi->irq, NULL,
tegra_qspi_isr_thread, IRQF_ONESHOT,
@ -1802,6 +1812,7 @@ static int tegra_qspi_probe(struct platform_device *pdev)
exit_free_irq:
free_irq(qspi_irq, tqspi);
exit_pm_disable:
pm_runtime_dont_use_autosuspend(&pdev->dev);
pm_runtime_force_suspend(&pdev->dev);
tegra_qspi_deinit_dma(tqspi);
return ret;
@ -1814,6 +1825,7 @@ static void tegra_qspi_remove(struct platform_device *pdev)
spi_unregister_controller(host);
free_irq(tqspi->irq, tqspi);
pm_runtime_dont_use_autosuspend(&pdev->dev);
pm_runtime_force_suspend(&pdev->dev);
tegra_qspi_deinit_dma(tqspi);
}
@ -1839,7 +1851,8 @@ static int __maybe_unused tegra_qspi_resume(struct device *dev)
tegra_qspi_writel(tqspi, tqspi->command1_reg, QSPI_COMMAND1);
tegra_qspi_writel(tqspi, tqspi->def_command2_reg, QSPI_COMMAND2);
pm_runtime_put(dev);
pm_runtime_mark_last_busy(dev);
pm_runtime_put_autosuspend(dev);
return spi_controller_resume(host);
}