From 06151158f2da4764479b4ec01688dc4bade6ce9d Mon Sep 17 00:00:00 2001 From: "Stanley.Miao" Date: Thu, 29 Jan 2009 08:57:12 -0800 Subject: ARM: OMAP: Fix McBSP spin_lock deadlock A spin_lock deadlock will occur when omap_mcbsp_request() is invoked. omap_mcbsp_request() \- clk_enable(mcbsp->clk) [takes and holds clockfw_lock] \- omap2_clk_enable() \- _omap2_clk_enable() \- omap_mcbsp_clk_enable() \- clk_enable(child clock) [tries for clockfw_lock again] mcbsp_clk is a virtual clock and it comprises several child clocks. when enable mcbsp_clk in omap_mcbsp_request(), the enable function of mcbsp_clk will enable its child clocks, then the deadlock occurs. The solution is to remove the virtual clock and enable these child clocks in omap_mcbsp_request() directly. Signed-off-by: Stanley.Miao Signed-off-by: Tony Lindgren --- arch/arm/plat-omap/include/mach/mcbsp.h | 6 ++-- arch/arm/plat-omap/mcbsp.c | 52 ++++++++++++++++++++++++--------- 2 files changed, 43 insertions(+), 15 deletions(-) (limited to 'arch/arm/plat-omap') diff --git a/arch/arm/plat-omap/include/mach/mcbsp.h b/arch/arm/plat-omap/include/mach/mcbsp.h index eef873db3d4..113c2466c86 100644 --- a/arch/arm/plat-omap/include/mach/mcbsp.h +++ b/arch/arm/plat-omap/include/mach/mcbsp.h @@ -344,7 +344,8 @@ struct omap_mcbsp_platform_data { u8 dma_rx_sync, dma_tx_sync; u16 rx_irq, tx_irq; struct omap_mcbsp_ops *ops; - char const *clk_name; + char const **clk_names; + int num_clks; }; struct omap_mcbsp { @@ -376,7 +377,8 @@ struct omap_mcbsp { /* Protect the field .free, while checking if the mcbsp is in use */ spinlock_t lock; struct omap_mcbsp_platform_data *pdata; - struct clk *clk; + struct clk **clks; + int num_clks; }; extern struct omap_mcbsp **mcbsp_ptr; extern int omap_mcbsp_count; diff --git a/arch/arm/plat-omap/mcbsp.c b/arch/arm/plat-omap/mcbsp.c index f2401a831f9..e5842e30e53 100644 --- a/arch/arm/plat-omap/mcbsp.c +++ b/arch/arm/plat-omap/mcbsp.c @@ -214,6 +214,7 @@ EXPORT_SYMBOL(omap_mcbsp_set_io_type); int omap_mcbsp_request(unsigned int id) { struct omap_mcbsp *mcbsp; + int i; int err; if (!omap_mcbsp_check_valid_id(id)) { @@ -225,7 +226,8 @@ int omap_mcbsp_request(unsigned int id) if (mcbsp->pdata && mcbsp->pdata->ops && mcbsp->pdata->ops->request) mcbsp->pdata->ops->request(id); - clk_enable(mcbsp->clk); + for (i = 0; i < mcbsp->num_clks; i++) + clk_enable(mcbsp->clks[i]); spin_lock(&mcbsp->lock); if (!mcbsp->free) { @@ -276,6 +278,7 @@ EXPORT_SYMBOL(omap_mcbsp_request); void omap_mcbsp_free(unsigned int id) { struct omap_mcbsp *mcbsp; + int i; if (!omap_mcbsp_check_valid_id(id)) { printk(KERN_ERR "%s: Invalid id (%d)\n", __func__, id + 1); @@ -286,7 +289,8 @@ void omap_mcbsp_free(unsigned int id) if (mcbsp->pdata && mcbsp->pdata->ops && mcbsp->pdata->ops->free) mcbsp->pdata->ops->free(id); - clk_disable(mcbsp->clk); + for (i = mcbsp->num_clks - 1; i >= 0; i--) + clk_disable(mcbsp->clks[i]); spin_lock(&mcbsp->lock); if (mcbsp->free) { @@ -872,6 +876,7 @@ static int __devinit omap_mcbsp_probe(struct platform_device *pdev) struct omap_mcbsp_platform_data *pdata = pdev->dev.platform_data; struct omap_mcbsp *mcbsp; int id = pdev->id - 1; + int i; int ret = 0; if (!pdata) { @@ -916,14 +921,25 @@ static int __devinit omap_mcbsp_probe(struct platform_device *pdev) mcbsp->dma_rx_sync = pdata->dma_rx_sync; mcbsp->dma_tx_sync = pdata->dma_tx_sync; - if (pdata->clk_name) - mcbsp->clk = clk_get(&pdev->dev, pdata->clk_name); - if (IS_ERR(mcbsp->clk)) { - dev_err(&pdev->dev, - "Invalid clock configuration for McBSP%d.\n", - mcbsp->id); - ret = PTR_ERR(mcbsp->clk); - goto err_clk; + if (pdata->num_clks) { + mcbsp->num_clks = pdata->num_clks; + mcbsp->clks = kzalloc(mcbsp->num_clks * sizeof(struct clk *), + GFP_KERNEL); + if (!mcbsp->clks) { + ret = -ENOMEM; + goto exit; + } + for (i = 0; i < mcbsp->num_clks; i++) { + mcbsp->clks[i] = clk_get(&pdev->dev, pdata->clk_names[i]); + if (IS_ERR(mcbsp->clks[i])) { + dev_err(&pdev->dev, + "Invalid %s configuration for McBSP%d.\n", + pdata->clk_names[i], mcbsp->id); + ret = PTR_ERR(mcbsp->clks[i]); + goto err_clk; + } + } + } mcbsp->pdata = pdata; @@ -932,6 +948,9 @@ static int __devinit omap_mcbsp_probe(struct platform_device *pdev) return 0; err_clk: + while (i--) + clk_put(mcbsp->clks[i]); + kfree(mcbsp->clks); iounmap(mcbsp->io_base); err_ioremap: mcbsp->free = 0; @@ -942,6 +961,7 @@ exit: static int __devexit omap_mcbsp_remove(struct platform_device *pdev) { struct omap_mcbsp *mcbsp = platform_get_drvdata(pdev); + int i; platform_set_drvdata(pdev, NULL); if (mcbsp) { @@ -950,12 +970,18 @@ static int __devexit omap_mcbsp_remove(struct platform_device *pdev) mcbsp->pdata->ops->free) mcbsp->pdata->ops->free(mcbsp->id); - clk_disable(mcbsp->clk); - clk_put(mcbsp->clk); + for (i = mcbsp->num_clks - 1; i >= 0; i--) { + clk_disable(mcbsp->clks[i]); + clk_put(mcbsp->clks[i]); + } iounmap(mcbsp->io_base); - mcbsp->clk = NULL; + if (mcbsp->num_clks) { + kfree(mcbsp->clks); + mcbsp->clks = NULL; + mcbsp->num_clks = 0; + } mcbsp->free = 0; mcbsp->dev = NULL; } -- cgit v1.2.3