From e1e4528f8c99624494043597859e7f9421832833 Mon Sep 17 00:00:00 2001 From: Suman Anna Date: Wed, 2 Jul 2014 18:00:59 -0500 Subject: hwspinlock/omap: enable module before reading SYSSTATUS register The number of hwspinlocks are determined based on the value read from the IP block's SYSSTATUS register. However, the module may not be enabled and clocked, and the read may result in a bus error. This particular issue is seen rather easily on AM33XX, since the module wakeup is software controlled, and it is disabled out of reset. Make sure the module is enabled and clocked before reading the SYSSTATUS register. Signed-off-by: Suman Anna [replace pm_runtime_put_sync with lenient pm_runtime_put] Signed-off-by: Ohad Ben-Cohen --- drivers/hwspinlock/omap_hwspinlock.c | 27 ++++++++++++++++++++------- 1 file changed, 20 insertions(+), 7 deletions(-) (limited to 'drivers') diff --git a/drivers/hwspinlock/omap_hwspinlock.c b/drivers/hwspinlock/omap_hwspinlock.c index 292869cc9034..c1e2cd4d85fe 100644 --- a/drivers/hwspinlock/omap_hwspinlock.c +++ b/drivers/hwspinlock/omap_hwspinlock.c @@ -98,10 +98,29 @@ static int omap_hwspinlock_probe(struct platform_device *pdev) if (!io_base) return -ENOMEM; + /* + * make sure the module is enabled and clocked before reading + * the module SYSSTATUS register + */ + pm_runtime_enable(&pdev->dev); + ret = pm_runtime_get_sync(&pdev->dev); + if (ret < 0) { + pm_runtime_put_noidle(&pdev->dev); + goto iounmap_base; + } + /* Determine number of locks */ i = readl(io_base + SYSSTATUS_OFFSET); i >>= SPINLOCK_NUMLOCKS_BIT_OFFSET; + /* + * runtime PM will make sure the clock of this module is + * enabled again iff at least one lock is requested + */ + ret = pm_runtime_put(&pdev->dev); + if (ret < 0) + goto iounmap_base; + /* one of the four lsb's must be set, and nothing else */ if (hweight_long(i & 0xf) != 1 || i > 8) { ret = -EINVAL; @@ -121,12 +140,6 @@ static int omap_hwspinlock_probe(struct platform_device *pdev) for (i = 0, hwlock = &bank->lock[0]; i < num_locks; i++, hwlock++) hwlock->priv = io_base + LOCK_BASE_OFFSET + sizeof(u32) * i; - /* - * runtime PM will make sure the clock of this module is - * enabled iff at least one lock is requested - */ - pm_runtime_enable(&pdev->dev); - ret = hwspin_lock_register(bank, &pdev->dev, &omap_hwspinlock_ops, pdata->base_id, num_locks); if (ret) @@ -135,9 +148,9 @@ static int omap_hwspinlock_probe(struct platform_device *pdev) return 0; reg_fail: - pm_runtime_disable(&pdev->dev); kfree(bank); iounmap_base: + pm_runtime_disable(&pdev->dev); iounmap(io_base); return ret; } -- cgit v1.2.3-59-g8ed1b