diff options
| author | Vishwaroop A <va@nvidia.com> | 2026-02-24 12:24:52 +0300 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2026-02-24 18:22:17 +0300 |
| commit | 7c12f6ead4672cb08b74e6f6115eb04dca8ccfa4 (patch) | |
| tree | 235f10c9dc349241ad2f212adfb41a7bf4a64b73 | |
| parent | 507a071d9868cb60e4e76f8a06fc8eb014f59ae4 (diff) | |
| download | linux-7c12f6ead4672cb08b74e6f6115eb04dca8ccfa4.tar.xz | |
spi: tegra210-quad: Add runtime autosuspend support
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>
| -rw-r--r-- | drivers/spi/spi-tegra210-quad.c | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/drivers/spi/spi-tegra210-quad.c b/drivers/spi/spi-tegra210-quad.c index 7ea5aa993596..7fac695b5142 100644 --- a/drivers/spi/spi-tegra210-quad.c +++ b/drivers/spi/spi-tegra210-quad.c @@ -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); } |