From 91b9deefedf4c35a01027ce38bed7299605026a3 Mon Sep 17 00:00:00 2001 From: Tony Lindgren Date: Thu, 15 Nov 2018 15:59:39 -0800 Subject: spi: omap2-mcspi: Add missing suspend and resume calls I've been wondering still about omap2-mcspi related suspend and resume flakeyness and looks like we're missing calls to spi_master_suspend() and spi_master_resume(). Adding those and using pm_runtime_force_suspend() and pm_runtime_force_resume() makes things work for suspend and resume and allows us to stop using noirq suspend and resume. And while at it, let's use SET_SYSTEM_SLEEP_PM_OPS to simplify things further. Signed-off-by: Tony Lindgren Signed-off-by: Mark Brown --- drivers/spi/spi-omap2-mcspi.c | 37 +++++++++++++++++++++++++------------ 1 file changed, 25 insertions(+), 12 deletions(-) (limited to 'drivers/spi') diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c index f024c3fc3679..2fd8881fcd65 100644 --- a/drivers/spi/spi-omap2-mcspi.c +++ b/drivers/spi/spi-omap2-mcspi.c @@ -1540,13 +1540,26 @@ static int omap2_mcspi_remove(struct platform_device *pdev) /* work with hotplug and coldplug */ MODULE_ALIAS("platform:omap2_mcspi"); -#ifdef CONFIG_SUSPEND -static int omap2_mcspi_suspend_noirq(struct device *dev) +static int __maybe_unused omap2_mcspi_suspend(struct device *dev) { - return pinctrl_pm_select_sleep_state(dev); + struct spi_master *master = dev_get_drvdata(dev); + struct omap2_mcspi *mcspi = spi_master_get_devdata(master); + int error; + + error = pinctrl_pm_select_sleep_state(dev); + if (error) + dev_warn(mcspi->dev, "%s: failed to set pins: %i\n", + __func__, error); + + error = spi_master_suspend(master); + if (error) + dev_warn(mcspi->dev, "%s: master suspend failed: %i\n", + __func__, error); + + return pm_runtime_force_suspend(dev); } -static int omap2_mcspi_resume_noirq(struct device *dev) +static int __maybe_unused omap2_mcspi_resume(struct device *dev) { struct spi_master *master = dev_get_drvdata(dev); struct omap2_mcspi *mcspi = spi_master_get_devdata(master); @@ -1557,17 +1570,17 @@ static int omap2_mcspi_resume_noirq(struct device *dev) dev_warn(mcspi->dev, "%s: failed to set pins: %i\n", __func__, error); - return 0; -} + error = spi_master_resume(master); + if (error) + dev_warn(mcspi->dev, "%s: master resume failed: %i\n", + __func__, error); -#else -#define omap2_mcspi_suspend_noirq NULL -#define omap2_mcspi_resume_noirq NULL -#endif + return pm_runtime_force_resume(dev); +} static const struct dev_pm_ops omap2_mcspi_pm_ops = { - .suspend_noirq = omap2_mcspi_suspend_noirq, - .resume_noirq = omap2_mcspi_resume_noirq, + SET_SYSTEM_SLEEP_PM_OPS(omap2_mcspi_suspend, + omap2_mcspi_resume) .runtime_resume = omap_mcspi_runtime_resume, }; -- cgit v1.2.3 From 56c1723426d3cfd4723bfbfce531d7b38bae6266 Mon Sep 17 00:00:00 2001 From: Lukas Wunner Date: Thu, 8 Nov 2018 08:06:10 +0100 Subject: spi: bcm2835: Avoid finishing transfer prematurely in IRQ mode MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The IRQ handler bcm2835_spi_interrupt() first reads as much as possible from the RX FIFO, then writes as much as possible to the TX FIFO. Afterwards it decides whether the transfer is finished by checking if the TX FIFO is empty. If very few bytes were written to the TX FIFO, they may already have been transmitted by the time the FIFO's emptiness is checked. As a result, the transfer will be declared finished and the chip will be reset without reading the corresponding received bytes from the RX FIFO. The odds of this happening increase with a high clock frequency (such that the TX FIFO drains quickly) and either passing "threadirqs" on the command line or enabling CONFIG_PREEMPT_RT_BASE (such that the IRQ handler may be preempted between filling the TX FIFO and checking its emptiness). Fix by instead checking whether rx_len has reached zero, which means that the transfer has been received in full. This is also more efficient as it avoids one bus read access per interrupt. Note that bcm2835_spi_transfer_one_poll() likewise uses rx_len to determine whether the transfer has finished. Signed-off-by: Lukas Wunner Fixes: e34ff011c70e ("spi: bcm2835: move to the transfer_one driver model") Cc: stable@vger.kernel.org # v4.1+ Cc: Mathias Duckeck Cc: Frank Pavlic Cc: Martin Sperl Cc: Noralf Trønnes Signed-off-by: Mark Brown --- drivers/spi/spi-bcm2835.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'drivers/spi') diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c index f35cc10772f6..fa7844a956c7 100644 --- a/drivers/spi/spi-bcm2835.c +++ b/drivers/spi/spi-bcm2835.c @@ -155,8 +155,7 @@ static irqreturn_t bcm2835_spi_interrupt(int irq, void *dev_id) /* Write as many bytes as possible to FIFO */ bcm2835_wr_fifo(bs); - /* based on flags decide if we can finish the transfer */ - if (bcm2835_rd(bs, BCM2835_SPI_CS) & BCM2835_SPI_CS_DONE) { + if (!bs->rx_len) { /* Transfer complete - reset SPI HW */ bcm2835_spi_reset_hw(master); /* wake up the framework */ -- cgit v1.2.3 From dbc944115eed48af110646992893dc43321368d8 Mon Sep 17 00:00:00 2001 From: Lukas Wunner Date: Thu, 8 Nov 2018 08:06:10 +0100 Subject: spi: bcm2835: Fix book-keeping of DMA termination MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit If submission of a DMA TX transfer succeeds but submission of the corresponding RX transfer does not, the BCM2835 SPI driver terminates the TX transfer but neglects to reset the dma_pending flag to false. Thus, if the next transfer uses interrupt mode (because it is shorter than BCM2835_SPI_DMA_MIN_LENGTH) and runs into a timeout, dmaengine_terminate_all() will be called both for TX (once more) and for RX (which was never started in the first place). Fix it. Signed-off-by: Lukas Wunner Fixes: 3ecd37edaa2a ("spi: bcm2835: enable dma modes for transfers meeting certain conditions") Cc: stable@vger.kernel.org # v4.2+ Cc: Mathias Duckeck Cc: Frank Pavlic Cc: Martin Sperl Cc: Noralf Trønnes Signed-off-by: Mark Brown --- drivers/spi/spi-bcm2835.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/spi') diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c index fa7844a956c7..594e9712ecbc 100644 --- a/drivers/spi/spi-bcm2835.c +++ b/drivers/spi/spi-bcm2835.c @@ -341,6 +341,7 @@ static int bcm2835_spi_transfer_one_dma(struct spi_master *master, if (ret) { /* need to reset on errors */ dmaengine_terminate_all(master->dma_tx); + bs->dma_pending = false; bcm2835_spi_reset_hw(master); return ret; } -- cgit v1.2.3 From e82b0b3828451c1cd331d9f304c6078fcd43b62e Mon Sep 17 00:00:00 2001 From: Lukas Wunner Date: Thu, 8 Nov 2018 08:06:10 +0100 Subject: spi: bcm2835: Fix race on DMA termination MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit If a DMA transfer finishes orderly right when spi_transfer_one_message() determines that it has timed out, the callbacks bcm2835_spi_dma_done() and bcm2835_spi_handle_err() race to call dmaengine_terminate_all(), potentially leading to double termination. Prevent by atomically changing the dma_pending flag before calling dmaengine_terminate_all(). Signed-off-by: Lukas Wunner Fixes: 3ecd37edaa2a ("spi: bcm2835: enable dma modes for transfers meeting certain conditions") Cc: stable@vger.kernel.org # v4.2+ Cc: Mathias Duckeck Cc: Frank Pavlic Cc: Martin Sperl Cc: Noralf Trønnes Signed-off-by: Mark Brown --- drivers/spi/spi-bcm2835.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) (limited to 'drivers/spi') diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c index 594e9712ecbc..774161bbcb2e 100644 --- a/drivers/spi/spi-bcm2835.c +++ b/drivers/spi/spi-bcm2835.c @@ -232,10 +232,9 @@ static void bcm2835_spi_dma_done(void *data) * is called the tx-dma must have finished - can't get to this * situation otherwise... */ - dmaengine_terminate_all(master->dma_tx); - - /* mark as no longer pending */ - bs->dma_pending = 0; + if (cmpxchg(&bs->dma_pending, true, false)) { + dmaengine_terminate_all(master->dma_tx); + } /* and mark as completed */; complete(&master->xfer_completion); @@ -617,10 +616,9 @@ static void bcm2835_spi_handle_err(struct spi_master *master, struct bcm2835_spi *bs = spi_master_get_devdata(master); /* if an error occurred and we have an active dma, then terminate */ - if (bs->dma_pending) { + if (cmpxchg(&bs->dma_pending, true, false)) { dmaengine_terminate_all(master->dma_tx); dmaengine_terminate_all(master->dma_rx); - bs->dma_pending = 0; } /* and reset */ bcm2835_spi_reset_hw(master); -- cgit v1.2.3