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[82.243.161.21]) by smtp.googlemail.com with ESMTPSA id r27sm1586429edx.33.2020.10.02.09.49.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 Oct 2020 09:49:36 -0700 (PDT) From: Jerome Brunet To: Ulf Hansson Cc: Jerome Brunet , Kevin Hilman , linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org, Brad Harper , Sebastian Andrzej Siewior Subject: [PATCH] mmc: meson-gx: remove IRQF_ONESHOT Date: Fri, 2 Oct 2020 18:49:15 +0200 Message-Id: <20201002164915.938217-1-jbrunet@baylibre.com> X-Mailer: git-send-email 2.25.4 MIME-Version: 1.0 X-Patchwork-Bot: notify Precedence: bulk List-ID: X-Mailing-List: linux-mmc@vger.kernel.org IRQF_ONESHOT was added to this driver to make sure the irq was not enabled again until the thread part of the irq had finished doing its job. Doing so upsets RT because, under RT, the hardirq part of the irq handler is not migrated to a thread if the irq is claimed with IRQF_ONESHOT. In this case, it has been reported to eventually trigger a deadlock with the led subsystem. Preventing RT from doing this migration was certainly not the intent, the description of IRQF_ONESHOT does not really reflect this constraint: > IRQF_ONESHOT - Interrupt is not reenabled after the hardirq handler finished. > Used by threaded interrupts which need to keep the > irq line disabled until the threaded handler has been run. This is exactly what this driver was trying to acheive so I'm still a bit confused whether this is a driver or an RT issue. Anyway, this can be solved driver side by manually disabling the IRQs instead of the relying on the IRQF_ONESHOT. IRQF_ONESHOT may then be removed while still making sure the irq won't trigger until the threaded part of the handler is done. Fixes: eb4d81127746 ("mmc: meson-gx: correct irq flag") Reported-by: Brad Harper Cc: Sebastian Andrzej Siewior Signed-off-by: Jerome Brunet Tested-by: Jerome Brunet Tested-by: Brad Harper --- drivers/mmc/host/meson-gx-mmc.c | 47 ++++++++++++++++++++------------- 1 file changed, 29 insertions(+), 18 deletions(-) diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c index 08a3b1c05acb..effc356db904 100644 --- a/drivers/mmc/host/meson-gx-mmc.c +++ b/drivers/mmc/host/meson-gx-mmc.c @@ -101,8 +101,7 @@ #define IRQ_RESP_STATUS BIT(14) #define IRQ_SDIO BIT(15) #define IRQ_EN_MASK \ - (IRQ_CRC_ERR | IRQ_TIMEOUTS | IRQ_END_OF_CHAIN | IRQ_RESP_STATUS |\ - IRQ_SDIO) + (IRQ_CRC_ERR | IRQ_TIMEOUTS | IRQ_END_OF_CHAIN) #define SD_EMMC_CMD_CFG 0x50 #define SD_EMMC_CMD_ARG 0x54 @@ -170,6 +169,7 @@ struct meson_host { dma_addr_t descs_dma_addr; int irq; + u32 irq_en; bool vqmmc_enabled; }; @@ -842,22 +842,24 @@ static irqreturn_t meson_mmc_irq(int irq, void *dev_id) struct meson_host *host = dev_id; struct mmc_command *cmd; struct mmc_data *data; - u32 irq_en, status, raw_status; + u32 status, raw_status; irqreturn_t ret = IRQ_NONE; - irq_en = readl(host->regs + SD_EMMC_IRQ_EN); + /* Disable irqs */ + writel(0, host->regs + SD_EMMC_IRQ_EN); + raw_status = readl(host->regs + SD_EMMC_STATUS); - status = raw_status & irq_en; + status = raw_status & host->irq_en; if (!status) { dev_dbg(host->dev, "Unexpected IRQ! irq_en 0x%08x - status 0x%08x\n", - irq_en, raw_status); - return IRQ_NONE; + host->irq_en, raw_status); + goto none; } if (WARN_ON(!host) || WARN_ON(!host->cmd)) - return IRQ_NONE; + goto none; /* ack all raised interrupts */ writel(status, host->regs + SD_EMMC_STATUS); @@ -908,6 +910,11 @@ static irqreturn_t meson_mmc_irq(int irq, void *dev_id) if (ret == IRQ_HANDLED) meson_mmc_request_done(host->mmc, cmd->mrq); +none: + /* Enable the irq again if the thread will not run */ + if (ret != IRQ_WAKE_THREAD) + writel(host->irq_en, host->regs + SD_EMMC_IRQ_EN); + return ret; } @@ -934,15 +941,17 @@ static irqreturn_t meson_mmc_irq_thread(int irq, void *dev_id) struct mmc_command *next_cmd, *cmd = host->cmd; struct mmc_data *data; unsigned int xfer_bytes; + int ret = IRQ_HANDLED; - if (WARN_ON(!cmd)) - return IRQ_NONE; + if (WARN_ON(!cmd)) { + ret = IRQ_NONE; + goto out; + } if (cmd->error) { meson_mmc_wait_desc_stop(host); meson_mmc_request_done(host->mmc, cmd->mrq); - - return IRQ_HANDLED; + goto out; } data = cmd->data; @@ -959,7 +968,10 @@ static irqreturn_t meson_mmc_irq_thread(int irq, void *dev_id) else meson_mmc_request_done(host->mmc, cmd->mrq); - return IRQ_HANDLED; +out: + /* Re-enable the irqs */ + writel(host->irq_en, host->regs + SD_EMMC_IRQ_EN); + return ret; } /* @@ -1133,13 +1145,12 @@ static int meson_mmc_probe(struct platform_device *pdev) /* clear, ack and enable interrupts */ writel(0, host->regs + SD_EMMC_IRQ_EN); - writel(IRQ_CRC_ERR | IRQ_TIMEOUTS | IRQ_END_OF_CHAIN, - host->regs + SD_EMMC_STATUS); - writel(IRQ_CRC_ERR | IRQ_TIMEOUTS | IRQ_END_OF_CHAIN, - host->regs + SD_EMMC_IRQ_EN); + host->irq_en = IRQ_EN_MASK; + writel(host->irq_en, host->regs + SD_EMMC_STATUS); + writel(host->irq_en, host->regs + SD_EMMC_IRQ_EN); ret = request_threaded_irq(host->irq, meson_mmc_irq, - meson_mmc_irq_thread, IRQF_ONESHOT, + meson_mmc_irq_thread, 0, dev_name(&pdev->dev), host); if (ret) goto err_init_clk;