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 <stanley.miao@windriver.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
diff --git a/arch/arm/plat-omap/mcbsp.c b/arch/arm/plat-omap/mcbsp.c
index f2401a8..e5842e3 100644
--- a/arch/arm/plat-omap/mcbsp.c
+++ b/arch/arm/plat-omap/mcbsp.c
@@ -214,6 +214,7 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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;
}