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[61.228.48.72]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2cf344bd3aesm28731535ad.26.2026.07.18.08.32.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 18 Jul 2026 08:32:58 -0700 (PDT) From: Shih-Yuan Lee To: Mark Brown Cc: linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, Shih-Yuan Lee Subject: [PATCH v13 2/3] spi: pxa2xx: fix runtime PM and interrupt handling in PIO mode Date: Sat, 18 Jul 2026 23:32:50 +0800 Message-Id: <20260718153251.7353-3-fourdollars@debian.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20260718153251.7353-1-fourdollars@debian.org> References: <20260718153251.7353-1-fourdollars@debian.org> Precedence: bulk X-Mailing-List: linux-spi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When operating in PIO mode on Intel LPSS SPI controllers, runtime PM autosuspend clock-gates the hardware block, causing PCIe Completion Timeouts on subsequent MMIO accesses. To fix this: - Scope PIO mode autosuspend lockout (pm_runtime_get_noresume() / put_sync()) strictly to LPSS controllers via is_lpss_ssp(), preserving autosuspend for non-LPSS SoCs. - Acquire pm_runtime_get_noresume() exactly once in pxa2xx_spi_probe() after spi_register_controller() succeeds, and release it via pm_runtime_put_sync() in pxa2xx_spi_remove(). Using pm_runtime_put_sync() ensures the runtime PM state machine transitions to RPM_SUSPENDED upon driver unbind, preventing active child count leaks on the parent LPSS power domain. - Track clock state using drv_data->clk_enabled in helper functions pxa2xx_spi_clk_enable/disable() to prevent clock count underflows on error paths. - Protect ssp_int() using drv_data->clk_enabled, drv_data->suspended, and checking pm_runtime_get_if_active() == 0 to return IRQ_NONE immediately, avoiding unclocked MMIO reads and level-triggered shared IRQ storms. - Register IRQ in probe only after enabling the clock and clearing suspended. - Overhaul pxa2xx_spi_remove() teardown sequence: disable SSP hardware IRQ, set suspended flag, synchronize IRQ, free IRQ, and disable clocks. - Guard MMIO access in pxa2xx_spi_runtime_suspend() with drv_data->clk_enabled check. Link: https://bugzilla.kernel.org/show_bug.cgi?id=108331 Signed-off-by: Shih-Yuan Lee --- drivers/spi/spi-pxa2xx.c | 138 +++++++++++++++++++++++++++++---------- drivers/spi/spi-pxa2xx.h | 3 + 2 files changed, 108 insertions(+), 33 deletions(-) diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c index 6291d7c2e06f..443800bffbeb 100644 --- a/drivers/spi/spi-pxa2xx.c +++ b/drivers/spi/spi-pxa2xx.c @@ -72,7 +72,12 @@ struct chip_data { #define LPSS_CAPS_CS_EN_SHIFT 9 #define LPSS_CAPS_CS_EN_MASK (0xf << LPSS_CAPS_CS_EN_SHIFT) -#define LPSS_PRIV_CLOCK_GATE 0x38 +/* Offsets from drv_data->lpss_base */ +#define LPSS_PRIV_RESETS 0x04 +#define LPSS_PRIV_RESETS_IDMA BIT(2) +#define LPSS_PRIV_RESETS_FUNC 0x3 + +#define LPSS_PRIV_CLOCK_GATE 0x38 #define LPSS_PRIV_CLOCK_GATE_CLK_CTL_MASK 0x3 #define LPSS_PRIV_CLOCK_GATE_CLK_CTL_FORCE_ON 0x3 #define LPSS_PRIV_CLOCK_GATE_CLK_CTL_FORCE_OFF 0x0 @@ -713,6 +718,28 @@ static void handle_bad_msg(struct driver_data *drv_data) dev_err(drv_data->ssp->dev, "bad message state in interrupt handler\n"); } +static int pxa2xx_spi_clk_enable(struct driver_data *drv_data) +{ + int status; + + if (drv_data->clk_enabled) + return 0; + + status = clk_prepare_enable(drv_data->ssp->clk); + if (status == 0) + drv_data->clk_enabled = true; + + return status; +} + +static void pxa2xx_spi_clk_disable(struct driver_data *drv_data) +{ + if (drv_data->clk_enabled) { + clk_disable_unprepare(drv_data->ssp->clk); + drv_data->clk_enabled = false; + } +} + static irqreturn_t ssp_int(int irq, void *dev_id) { struct driver_data *drv_data = dev_id; @@ -721,19 +748,18 @@ static irqreturn_t ssp_int(int irq, void *dev_id) u32 status; /* - * The IRQ might be shared with other peripherals so we must first - * check that are we RPM suspended or not. If we are we assume that - * the IRQ was not for us (we shouldn't be RPM suspended when the - * interrupt is enabled). + * The IRQ might be shared with other peripherals or trigger during + * power state transitions. First check if device is suspended or if + * clock is disabled; if so, return IRQ_NONE immediately to avoid + * unclocked MMIO reads. */ - if (pm_runtime_suspended(drv_data->ssp->dev)) + if (drv_data->suspended || !drv_data->clk_enabled) return IRQ_NONE; /* - * If the device is not yet in RPM suspended state and we get an - * interrupt that is meant for another device, check if status bits - * are all set to one. That means that the device is already - * powered off. + * If the device is not yet suspended and we get an interrupt that is + * meant for another device, check if status bits are all set to one. + * That means that the device is already powered off. */ status = pxa2xx_spi_read(drv_data, SSSR); if (status == ~0) @@ -1288,6 +1314,7 @@ int pxa2xx_spi_probe(struct device *dev, struct ssp_device *ssp, drv_data->controller = controller; drv_data->controller_info = platform_info; drv_data->ssp = ssp; + drv_data->suspended = true; /* Start suspended until clock is enabled */ /* The spi->mode bits understood by this driver: */ controller->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LOOP; @@ -1330,10 +1357,6 @@ int pxa2xx_spi_probe(struct device *dev, struct ssp_device *ssp, | SSSR_ROR | SSSR_TUR; } - status = request_irq(ssp->irq, ssp_int, IRQF_SHARED, dev_name(dev), - drv_data); - if (status < 0) - return dev_err_probe(dev, status, "cannot get IRQ %d\n", ssp->irq); /* Setup DMA if requested */ if (platform_info->enable_dma) { @@ -1352,9 +1375,18 @@ int pxa2xx_spi_probe(struct device *dev, struct ssp_device *ssp, } /* Enable SOC clock */ - status = clk_prepare_enable(ssp->clk); + status = pxa2xx_spi_clk_enable(drv_data); if (status) - goto out_error_dma_irq_alloc; + goto out_error_dma_alloc; + + drv_data->suspended = false; + + status = request_irq(ssp->irq, ssp_int, IRQF_SHARED, dev_name(dev), + drv_data); + if (status < 0) { + status = dev_err_probe(dev, status, "cannot get IRQ %d\n", ssp->irq); + goto out_error_clock_enabled; + } controller->max_speed_hz = clk_get_rate(ssp->clk); /* @@ -1434,7 +1466,7 @@ int pxa2xx_spi_probe(struct device *dev, struct ssp_device *ssp, "ready", GPIOD_OUT_LOW); if (IS_ERR(drv_data->gpiod_ready)) { status = PTR_ERR(drv_data->gpiod_ready); - goto out_error_clock_enabled; + goto out_error_irq_alloc; } } @@ -1443,17 +1475,22 @@ int pxa2xx_spi_probe(struct device *dev, struct ssp_device *ssp, status = spi_register_controller(controller); if (status) { dev_err_probe(dev, status, "problem registering SPI controller\n"); - goto out_error_clock_enabled; + goto out_error_irq_alloc; } + if (is_lpss_ssp(drv_data) && !platform_info->enable_dma) + pm_runtime_get_noresume(dev); + return status; +out_error_irq_alloc: + free_irq(ssp->irq, drv_data); + out_error_clock_enabled: - clk_disable_unprepare(ssp->clk); + pxa2xx_spi_clk_disable(drv_data); -out_error_dma_irq_alloc: +out_error_dma_alloc: pxa2xx_spi_dma_release(drv_data); - free_irq(ssp->irq, drv_data); return status; } @@ -1466,16 +1503,26 @@ void pxa2xx_spi_remove(struct device *dev) spi_unregister_controller(drv_data->controller); - /* Disable the SSP at the peripheral and SOC level */ + /* Disable SSP interrupt generation on hardware level while clock is active */ pxa_ssp_disable(ssp); - clk_disable_unprepare(ssp->clk); - /* Release DMA */ - if (drv_data->controller_info->enable_dma) - pxa2xx_spi_dma_release(drv_data); + /* Mark as suspended to prevent further IRQ handling */ + drv_data->suspended = true; + + /* Wait for any pending interrupt handlers to complete */ + synchronize_irq(ssp->irq); /* Release IRQ */ free_irq(ssp->irq, drv_data); + + /* Safe to disable the SSP clock now */ + pxa2xx_spi_clk_disable(drv_data); + + /* Release DMA */ + if (drv_data->controller_info->enable_dma) + pxa2xx_spi_dma_release(drv_data); + else if (is_lpss_ssp(drv_data)) + pm_runtime_put_sync(dev); } EXPORT_SYMBOL_NS_GPL(pxa2xx_spi_remove, "SPI_PXA2xx"); @@ -1490,10 +1537,10 @@ static int pxa2xx_spi_suspend(struct device *dev) return status; pxa_ssp_disable(ssp); + drv_data->suspended = true; + synchronize_irq(ssp->irq); - if (!pm_runtime_suspended(dev)) - clk_disable_unprepare(ssp->clk); - + pxa2xx_spi_clk_disable(drv_data); return 0; } @@ -1505,28 +1552,53 @@ static int pxa2xx_spi_resume(struct device *dev) /* Enable the SSP clock */ if (!pm_runtime_suspended(dev)) { - status = clk_prepare_enable(ssp->clk); + status = pxa2xx_spi_clk_enable(drv_data); if (status) return status; } + if (is_lpss_ssp(drv_data)) + lpss_ssp_setup(drv_data); + + drv_data->suspended = false; + /* Start the queue running */ - return spi_controller_resume(drv_data->controller); + status = spi_controller_resume(drv_data->controller); + if (status) { + drv_data->suspended = true; + synchronize_irq(ssp->irq); + pxa2xx_spi_clk_disable(drv_data); + return status; + } + + return 0; } static int pxa2xx_spi_runtime_suspend(struct device *dev) { struct driver_data *drv_data = dev_get_drvdata(dev); - clk_disable_unprepare(drv_data->ssp->clk); + if (!drv_data->clk_enabled) + return 0; + + pxa_ssp_disable(drv_data->ssp); + drv_data->suspended = true; + synchronize_irq(drv_data->ssp->irq); + pxa2xx_spi_clk_disable(drv_data); return 0; } static int pxa2xx_spi_runtime_resume(struct device *dev) { struct driver_data *drv_data = dev_get_drvdata(dev); + int status; + + status = pxa2xx_spi_clk_enable(drv_data); + if (status) + return status; - return clk_prepare_enable(drv_data->ssp->clk); + drv_data->suspended = false; + return 0; } EXPORT_NS_GPL_DEV_PM_OPS(pxa2xx_spi_pm_ops, SPI_PXA2xx) = { diff --git a/drivers/spi/spi-pxa2xx.h b/drivers/spi/spi-pxa2xx.h index 447be0369384..44f37bf9c519 100644 --- a/drivers/spi/spi-pxa2xx.h +++ b/drivers/spi/spi-pxa2xx.h @@ -72,6 +72,9 @@ struct driver_data { void __iomem *lpss_base; + bool suspended; + bool clk_enabled; + /* Optional slave FIFO ready signal */ struct gpio_desc *gpiod_ready; }; -- 2.39.5