diff options
| -rw-r--r-- | recipes-kernel/linux/linux-imx-rt-3.14.28/0004-imx-sdma-channel-use-raw-spinlock.patch | 95 | ||||
| -rw-r--r-- | recipes-kernel/linux/linux-imx-rt_3.14.28.bb | 1 |
2 files changed, 96 insertions, 0 deletions
diff --git a/recipes-kernel/linux/linux-imx-rt-3.14.28/0004-imx-sdma-channel-use-raw-spinlock.patch b/recipes-kernel/linux/linux-imx-rt-3.14.28/0004-imx-sdma-channel-use-raw-spinlock.patch new file mode 100644 index 00000000..da36213c --- /dev/null +++ b/recipes-kernel/linux/linux-imx-rt-3.14.28/0004-imx-sdma-channel-use-raw-spinlock.patch @@ -0,0 +1,95 @@ +Work around CPU stalls in the imx-sdma driver by replacing spinlocks +with raw spinlocks. This prevents preemption during the spinlock's +critical section, as is the case on non PREEMPT_RT kernels. + +Without this patch, the following error can occur, for example when +using the audio codec on an iMX6Q Sabre SD board: + +INFO: rcu_preempt self-detected stall on CPU { 0} (t=2100 jiffies g=106 c=105 q=93) +CPU: 0 PID: 120 Comm: irq/34-sdma Not tainted 3.14.28-rt25-1.0.0_ga+g91cf351 #1 +[<80014a8c>] (unwind_backtrace) from [<8001173c>] (show_stack+0x10/0x14) +[<8001173c>] (show_stack) from [<806ee750>] (dump_stack+0x7c/0xc8) +[<806ee750>] (dump_stack) from [<800771c8>] (rcu_check_callbacks+0x454/0x888) +[<800771c8>] (rcu_check_callbacks) from [<80037f28>] (update_process_times+0x40/0x5c) +[<80037f28>] (update_process_times) from [<80082230>] (tick_sched_timer+0x4c/0x78) +[<80082230>] (tick_sched_timer) from [<8004bf30>] (__run_hrtimer.isra.34+0x74/0x124) +[<8004bf30>] (__run_hrtimer.isra.34) from [<8004cbb0>] (hrtimer_interrupt+0x154/0x3ac) +[<8004cbb0>] (hrtimer_interrupt) from [<80014464>] (twd_handler+0x30/0x38) +[<80014464>] (twd_handler) from [<8006fa2c>] (handle_percpu_devid_irq+0x6c/0x84) +[<8006fa2c>] (handle_percpu_devid_irq) from [<8006bc64>] (generic_handle_irq+0x2c/0x3c) +[<8006bc64>] (generic_handle_irq) from [<8000ed8c>] (handle_IRQ+0x40/0x90) +[<8000ed8c>] (handle_IRQ) from [<8000856c>] (gic_handle_irq+0x2c/0x5c) +[<8000856c>] (gic_handle_irq) from [<80012240>] (__irq_svc+0x40/0x84) +Exception stack(0xa840feb8 to 0xa840ff00) +fea0: a8007a28 00000002 +fec0: 00000001 0000a6a6 a80079c0 a8007a28 a83ea080 00000000 a80079c0 a83ea080 +fee0: 285190f0 00000000 00000000 a840ff00 8006d04c 806f3070 20030113 ffffffff +[<80012240>] (__irq_svc) from [<806f3070>] (_raw_spin_unlock_irq+0x20/0x60) +[<806f3070>] (_raw_spin_unlock_irq) from [<8006d04c>] (irq_finalize_oneshot.part.37+0x70/0xcc) +[<8006d04c>] (irq_finalize_oneshot.part.37) from [<8006d148>] (irq_forced_thread_fn+0x60/0x64) +[<8006d148>] (irq_forced_thread_fn) from [<8006d3dc>] (irq_thread+0x138/0x1a4) +[<8006d3dc>] (irq_thread) from [<8004913c>] (kthread+0xbc/0xd4) +[<8004913c>] (kthread) from [<8000e538>] (ret_from_fork+0x14/0x3c) + +Upstream-Status: Pending + +Signed-off-by: Dominic Sacré <dominic.sacre@gmx.de> + +diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c +index bae2ea8..74ff5a0 100644 +--- a/drivers/dma/imx-sdma.c ++++ b/drivers/dma/imx-sdma.c +@@ -343,7 +343,7 @@ struct sdma_engine { + struct dma_device dma_device; + struct clk *clk_ipg; + struct clk *clk_ahb; +- spinlock_t channel_0_lock; ++ raw_spinlock_t channel_0_lock; + u32 script_number; + struct sdma_script_start_addrs *script_addrs; + const struct sdma_driver_data *drvdata; +@@ -593,7 +593,7 @@ static int sdma_load_script(struct sdma_engine *sdma, void *buf, int size, + return -ENOMEM; + } + +- spin_lock_irqsave(&sdma->channel_0_lock, flags); ++ raw_spin_lock_irqsave(&sdma->channel_0_lock, flags); + + bd0->mode.command = C0_SETPM; + bd0->mode.status = BD_DONE | BD_INTR | BD_WRAP | BD_EXTD; +@@ -605,7 +605,7 @@ static int sdma_load_script(struct sdma_engine *sdma, void *buf, int size, + + ret = sdma_run_channel0(sdma); + +- spin_unlock_irqrestore(&sdma->channel_0_lock, flags); ++ raw_spin_unlock_irqrestore(&sdma->channel_0_lock, flags); + + if (use_iram) + gen_pool_free(sdma->iram_pool, (unsigned long)buf_virt, size); +@@ -880,7 +880,7 @@ static int sdma_load_context(struct sdma_channel *sdmac) + dev_dbg(sdma->dev, "event_mask0 = 0x%08x\n", (u32)sdmac->event_mask[0]); + dev_dbg(sdma->dev, "event_mask1 = 0x%08x\n", (u32)sdmac->event_mask[1]); + +- spin_lock_irqsave(&sdma->channel_0_lock, flags); ++ raw_spin_lock_irqsave(&sdma->channel_0_lock, flags); + + memset(context, 0, sizeof(*context)); + context->channel_state.pc = load_address; +@@ -906,7 +906,7 @@ static int sdma_load_context(struct sdma_channel *sdmac) + bd0->ext_buffer_addr = 2048 + (sizeof(*context) / 4) * channel; + ret = sdma_run_channel0(sdma); + +- spin_unlock_irqrestore(&sdma->channel_0_lock, flags); ++ raw_spin_unlock_irqrestore(&sdma->channel_0_lock, flags); + + return ret; + } +@@ -1881,7 +1881,7 @@ static int __init sdma_probe(struct platform_device *pdev) + if (!sdma) + return -ENOMEM; + +- spin_lock_init(&sdma->channel_0_lock); ++ raw_spin_lock_init(&sdma->channel_0_lock); + + sdma->dev = &pdev->dev; + sdma->drvdata = drvdata; diff --git a/recipes-kernel/linux/linux-imx-rt_3.14.28.bb b/recipes-kernel/linux/linux-imx-rt_3.14.28.bb index f5cb5806..b9a8bf0c 100644 --- a/recipes-kernel/linux/linux-imx-rt_3.14.28.bb +++ b/recipes-kernel/linux/linux-imx-rt_3.14.28.bb @@ -23,6 +23,7 @@ SRC_URI += "\ file://0001-fix-build.patch \ file://0002-fix-build-with-rt-enabled.patch \ file://0003-no-split-ptlocks.patch \ + file://0004-imx-sdma-channel-use-raw-spinlock.patch \ " SRC_URI[rt-patch1.md5sum] = "28bfd1e14ccab1ea1fb48f56f982d80c" |