linux-fslc-imx-rt: Upgrade to 4.1.15-1.0.0 GA2.1

Use patch 4.1.19-rt22 (which applies cleanly) despite the fact that the
kernel is currently based on 4.1.20, because 4.1.20-rt23 is not yet
available at a stable URL.

The same issues that needed to be patched in 3.14 are still present in
4.1, so update the patches and defconfig accordingly to apply to the
new kernel.

Signed-off-by: Dominic Sacré <dominic.sacre@gmx.de>
Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>

1 files changed, 126 insertions, 0 deletions

diff --git a/recipes-kernel/linux/linux-fslc-imx-rt/0003-Work-around-CPU-stalls-in-the-imx-sdma-driver.patch b/recipes-kernel/linux/linux-fslc-imx-rt/0003-Work-around-CPU-stalls-in-the-imx-sdma-driver.patch
new file mode 100644
index 0000000..93200c6
--- /dev/null
+++ b/recipes-kernel/linux/linux-fslc-imx-rt/0003-Work-around-CPU-stalls-in-the-imx-sdma-driver.patch
@@ -0,0 +1,126 @@
+From f7cba8d49a980909cea48c5b9dcfefc6e13fef0b Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Dominic=20Sacr=C3=A9?= <dominic.sacre@gmx.de>
+Date: Fri, 29 Apr 2016 15:48:40 +0200
+Subject: [PATCH] Work around CPU stalls in the imx-sdma driver
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Replace 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 i.MX6Q SabreSD 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>
+---
+ drivers/dma/imx-sdma.c | 16 ++++++++--------
+ 1 file changed, 8 insertions(+), 8 deletions(-)
+
+diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
+index 31b7fed..bb7d6aa 100644
+--- a/drivers/dma/imx-sdma.c
++++ b/drivers/dma/imx-sdma.c
+@@ -408,7 +408,7 @@ 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;
+@@ -700,7 +700,7 @@ 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;
+@@ -712,7 +712,7 @@ 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);
+@@ -979,7 +979,7 @@ 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;
+@@ -1005,7 +1005,7 @@ 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);
+ 
+        sdmac->context_loaded = true;
+ 
+@@ -1019,7 +1019,7 @@ static int sdma_save_restore_context(struct sdma_engine *sdma, bool save)
+        unsigned long flags;
+        int ret;
+ 
+-       spin_lock_irqsave(&sdma->channel_0_lock, flags);
++       raw_spin_lock_irqsave(&sdma->channel_0_lock, flags);
+ 
+        if (save)
+                bd0->mode.command = C0_GETDM;
+@@ -1032,7 +1032,7 @@ static int sdma_save_restore_context(struct sdma_engine *sdma, bool save)
+        bd0->ext_buffer_addr = 2048;
+        ret = sdma_run_channel0(sdma);
+ 
+-       spin_unlock_irqrestore(&sdma->channel_0_lock, flags);
++       raw_spin_unlock_irqrestore(&sdma->channel_0_lock, flags);
+ 
+        return ret;
+ }
+@@ -2152,7 +2152,7 @@ static int 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;
+-- 
+2.8.1
+