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-rw-r--r--recipes-kernel/linux/linux-imx-rt-3.14.28/0004-imx-sdma-channel-use-raw-spinlock.patch95
-rw-r--r--recipes-kernel/linux/linux-imx-rt_3.14.28.bb1
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 @@
1Work around CPU stalls in the imx-sdma driver by replacing spinlocks
2with raw spinlocks. This prevents preemption during the spinlock's
3critical section, as is the case on non PREEMPT_RT kernels.
4
5Without this patch, the following error can occur, for example when
6using the audio codec on an iMX6Q Sabre SD board:
7
8INFO: rcu_preempt self-detected stall on CPU { 0} (t=2100 jiffies g=106 c=105 q=93)
9CPU: 0 PID: 120 Comm: irq/34-sdma Not tainted 3.14.28-rt25-1.0.0_ga+g91cf351 #1
10[<80014a8c>] (unwind_backtrace) from [<8001173c>] (show_stack+0x10/0x14)
11[<8001173c>] (show_stack) from [<806ee750>] (dump_stack+0x7c/0xc8)
12[<806ee750>] (dump_stack) from [<800771c8>] (rcu_check_callbacks+0x454/0x888)
13[<800771c8>] (rcu_check_callbacks) from [<80037f28>] (update_process_times+0x40/0x5c)
14[<80037f28>] (update_process_times) from [<80082230>] (tick_sched_timer+0x4c/0x78)
15[<80082230>] (tick_sched_timer) from [<8004bf30>] (__run_hrtimer.isra.34+0x74/0x124)
16[<8004bf30>] (__run_hrtimer.isra.34) from [<8004cbb0>] (hrtimer_interrupt+0x154/0x3ac)
17[<8004cbb0>] (hrtimer_interrupt) from [<80014464>] (twd_handler+0x30/0x38)
18[<80014464>] (twd_handler) from [<8006fa2c>] (handle_percpu_devid_irq+0x6c/0x84)
19[<8006fa2c>] (handle_percpu_devid_irq) from [<8006bc64>] (generic_handle_irq+0x2c/0x3c)
20[<8006bc64>] (generic_handle_irq) from [<8000ed8c>] (handle_IRQ+0x40/0x90)
21[<8000ed8c>] (handle_IRQ) from [<8000856c>] (gic_handle_irq+0x2c/0x5c)
22[<8000856c>] (gic_handle_irq) from [<80012240>] (__irq_svc+0x40/0x84)
23Exception stack(0xa840feb8 to 0xa840ff00)
24fea0: a8007a28 00000002
25fec0: 00000001 0000a6a6 a80079c0 a8007a28 a83ea080 00000000 a80079c0 a83ea080
26fee0: 285190f0 00000000 00000000 a840ff00 8006d04c 806f3070 20030113 ffffffff
27[<80012240>] (__irq_svc) from [<806f3070>] (_raw_spin_unlock_irq+0x20/0x60)
28[<806f3070>] (_raw_spin_unlock_irq) from [<8006d04c>] (irq_finalize_oneshot.part.37+0x70/0xcc)
29[<8006d04c>] (irq_finalize_oneshot.part.37) from [<8006d148>] (irq_forced_thread_fn+0x60/0x64)
30[<8006d148>] (irq_forced_thread_fn) from [<8006d3dc>] (irq_thread+0x138/0x1a4)
31[<8006d3dc>] (irq_thread) from [<8004913c>] (kthread+0xbc/0xd4)
32[<8004913c>] (kthread) from [<8000e538>] (ret_from_fork+0x14/0x3c)
33
34Upstream-Status: Pending
35
36Signed-off-by: Dominic Sacré <dominic.sacre@gmx.de>
37
38diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
39index bae2ea8..74ff5a0 100644
40--- a/drivers/dma/imx-sdma.c
41+++ b/drivers/dma/imx-sdma.c
42@@ -343,7 +343,7 @@ struct sdma_engine {
43 struct dma_device dma_device;
44 struct clk *clk_ipg;
45 struct clk *clk_ahb;
46- spinlock_t channel_0_lock;
47+ raw_spinlock_t channel_0_lock;
48 u32 script_number;
49 struct sdma_script_start_addrs *script_addrs;
50 const struct sdma_driver_data *drvdata;
51@@ -593,7 +593,7 @@ static int sdma_load_script(struct sdma_engine *sdma, void *buf, int size,
52 return -ENOMEM;
53 }
54
55- spin_lock_irqsave(&sdma->channel_0_lock, flags);
56+ raw_spin_lock_irqsave(&sdma->channel_0_lock, flags);
57
58 bd0->mode.command = C0_SETPM;
59 bd0->mode.status = BD_DONE | BD_INTR | BD_WRAP | BD_EXTD;
60@@ -605,7 +605,7 @@ static int sdma_load_script(struct sdma_engine *sdma, void *buf, int size,
61
62 ret = sdma_run_channel0(sdma);
63
64- spin_unlock_irqrestore(&sdma->channel_0_lock, flags);
65+ raw_spin_unlock_irqrestore(&sdma->channel_0_lock, flags);
66
67 if (use_iram)
68 gen_pool_free(sdma->iram_pool, (unsigned long)buf_virt, size);
69@@ -880,7 +880,7 @@ static int sdma_load_context(struct sdma_channel *sdmac)
70 dev_dbg(sdma->dev, "event_mask0 = 0x%08x\n", (u32)sdmac->event_mask[0]);
71 dev_dbg(sdma->dev, "event_mask1 = 0x%08x\n", (u32)sdmac->event_mask[1]);
72
73- spin_lock_irqsave(&sdma->channel_0_lock, flags);
74+ raw_spin_lock_irqsave(&sdma->channel_0_lock, flags);
75
76 memset(context, 0, sizeof(*context));
77 context->channel_state.pc = load_address;
78@@ -906,7 +906,7 @@ static int sdma_load_context(struct sdma_channel *sdmac)
79 bd0->ext_buffer_addr = 2048 + (sizeof(*context) / 4) * channel;
80 ret = sdma_run_channel0(sdma);
81
82- spin_unlock_irqrestore(&sdma->channel_0_lock, flags);
83+ raw_spin_unlock_irqrestore(&sdma->channel_0_lock, flags);
84
85 return ret;
86 }
87@@ -1881,7 +1881,7 @@ static int __init sdma_probe(struct platform_device *pdev)
88 if (!sdma)
89 return -ENOMEM;
90
91- spin_lock_init(&sdma->channel_0_lock);
92+ raw_spin_lock_init(&sdma->channel_0_lock);
93
94 sdma->dev = &pdev->dev;
95 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 += "\
23 file://0001-fix-build.patch \ 23 file://0001-fix-build.patch \
24 file://0002-fix-build-with-rt-enabled.patch \ 24 file://0002-fix-build-with-rt-enabled.patch \
25 file://0003-no-split-ptlocks.patch \ 25 file://0003-no-split-ptlocks.patch \
26 file://0004-imx-sdma-channel-use-raw-spinlock.patch \
26" 27"
27 28
28SRC_URI[rt-patch1.md5sum] = "28bfd1e14ccab1ea1fb48f56f982d80c" 29SRC_URI[rt-patch1.md5sum] = "28bfd1e14ccab1ea1fb48f56f982d80c"