Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756530Ab3I2TdK (ORCPT ); Sun, 29 Sep 2013 15:33:10 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:59875 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756083Ab3I2T3y (ORCPT ); Sun, 29 Sep 2013 15:29:54 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Solomon Peachy , "John W. Linville" Subject: [ 70/71] cw1200: Dont perform SPI transfers in interrupt context Date: Sun, 29 Sep 2013 12:28:22 -0700 Message-Id: <20130929192648.304161702@linuxfoundation.org> X-Mailer: git-send-email 1.8.4.6.g82e253f.dirty In-Reply-To: <20130929192643.539596256@linuxfoundation.org> References: <20130929192643.539596256@linuxfoundation.org> User-Agent: quilt/0.60-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4669 Lines: 142 3.11-stable review patch. If anyone has any objections, please let me know. ------------------ From: Solomon Peachy commit aec8e88c947b7017e2b4bbcb68a4bfc4a1f8ad35 upstream. When we get an interrupt from the hardware, the first thing the driver does is tell the device to mask off the interrupt line. Unfortunately this involves a SPI transaction in interrupt context. Some (most?) SPI controllers perform the transfer asynchronously and try to sleep. This is bad, and triggers a BUG(). So, work around this by using adding a hwbus hook for the cw1200 driver core to call. The cw1200_spi driver translates this into irq_disable()/irq_enable() calls instead, which can safely be called in interrupt context. Apparently the platforms I used to develop the cw1200_spi driver used synchronous spi_sync() implementations, which is why this didn't surface until now. Many thanks to Dave Sizeburns for the inital bug report and his services as a tester. Signed-off-by: Solomon Peachy Signed-off-by: John W. Linville Signed-off-by: Greg Kroah-Hartman --- drivers/net/wireless/cw1200/cw1200_spi.c | 19 ++++++++++++++++--- drivers/net/wireless/cw1200/fwio.c | 2 +- drivers/net/wireless/cw1200/hwbus.h | 1 + drivers/net/wireless/cw1200/hwio.c | 15 +++++++++++++++ 4 files changed, 33 insertions(+), 4 deletions(-) --- a/drivers/net/wireless/cw1200/cw1200_spi.c +++ b/drivers/net/wireless/cw1200/cw1200_spi.c @@ -42,6 +42,7 @@ struct hwbus_priv { spinlock_t lock; /* Serialize all bus operations */ wait_queue_head_t wq; int claimed; + int irq_disabled; }; #define SDIO_TO_SPI_ADDR(addr) ((addr & 0x1f)>>2) @@ -237,6 +238,8 @@ static irqreturn_t cw1200_spi_irq_handle struct hwbus_priv *self = dev_id; if (self->core) { + disable_irq_nosync(self->func->irq); + self->irq_disabled = 1; cw1200_irq_handler(self->core); return IRQ_HANDLED; } else { @@ -270,13 +273,22 @@ exit: static int cw1200_spi_irq_unsubscribe(struct hwbus_priv *self) { - int ret = 0; - pr_debug("SW IRQ unsubscribe\n"); disable_irq_wake(self->func->irq); free_irq(self->func->irq, self); - return ret; + return 0; +} + +static int cw1200_spi_irq_enable(struct hwbus_priv *self, int enable) +{ + /* Disables are handled by the interrupt handler */ + if (enable && self->irq_disabled) { + enable_irq(self->func->irq); + self->irq_disabled = 0; + } + + return 0; } static int cw1200_spi_off(const struct cw1200_platform_data_spi *pdata) @@ -356,6 +368,7 @@ static struct hwbus_ops cw1200_spi_hwbus .unlock = cw1200_spi_unlock, .align_size = cw1200_spi_align_size, .power_mgmt = cw1200_spi_pm, + .irq_enable = cw1200_spi_irq_enable, }; /* Probe Function to be called by SPI stack when device is discovered */ --- a/drivers/net/wireless/cw1200/fwio.c +++ b/drivers/net/wireless/cw1200/fwio.c @@ -485,7 +485,7 @@ int cw1200_load_firmware(struct cw1200_c /* Enable interrupt signalling */ priv->hwbus_ops->lock(priv->hwbus_priv); - ret = __cw1200_irq_enable(priv, 1); + ret = __cw1200_irq_enable(priv, 2); priv->hwbus_ops->unlock(priv->hwbus_priv); if (ret < 0) goto unsubscribe; --- a/drivers/net/wireless/cw1200/hwbus.h +++ b/drivers/net/wireless/cw1200/hwbus.h @@ -28,6 +28,7 @@ struct hwbus_ops { void (*unlock)(struct hwbus_priv *self); size_t (*align_size)(struct hwbus_priv *self, size_t size); int (*power_mgmt)(struct hwbus_priv *self, bool suspend); + int (*irq_enable)(struct hwbus_priv *self, int enable); }; #endif /* CW1200_HWBUS_H */ --- a/drivers/net/wireless/cw1200/hwio.c +++ b/drivers/net/wireless/cw1200/hwio.c @@ -273,6 +273,21 @@ int __cw1200_irq_enable(struct cw1200_co u16 val16; int ret; + /* We need to do this hack because the SPI layer can sleep on I/O + and the general path involves I/O to the device in interrupt + context. + + However, the initial enable call needs to go to the hardware. + + We don't worry about shutdown because we do a full reset which + clears the interrupt enabled bits. + */ + if (priv->hwbus_ops->irq_enable) { + ret = priv->hwbus_ops->irq_enable(priv->hwbus_priv, enable); + if (ret || enable < 2) + return ret; + } + if (HIF_8601_SILICON == priv->hw_type) { ret = __cw1200_reg_read_32(priv, ST90TDS_CONFIG_REG_ID, &val32); if (ret < 0) { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/