[PATCH 5.12 004/178] dmaengine: xilinx: dpdma: initialize registers before request_irq

Greg Kroah-Hartman
2021-06-21T16:37:59Z

From: Quanyang Wang <quanyang.wang@windriver.com>

[ Upstream commit 538ea65a9fd1194352a41313bff876b74b5d90c5 ]

In some scenarios (kdump), dpdma hardware irqs has been enabled when
calling request_irq in probe function, and then the dpdma irq handler
xilinx_dpdma_irq_handler is invoked to access xdev->chan[i]. But at
this moment xdev->chan[i] hasn't been initialized.

We should ensure the dpdma controller to be in a consistent and
clean state before further initialization. So add dpdma_hw_init()
to do this.

Furthermore, in xilinx_dpdma_disable_irq, disable all interrupts
instead of error interrupts.

This patch is to fix the kdump kernel crash as below:

[ 3.696128] Unable to handle kernel NULL pointer dereference at virtual address 000000000000012c
[ 3.696710] xilinx-zynqmp-dpdma fd4c0000.dma-controller: Xilinx DPDMA engine is probed
[ 3.704900] Mem abort info:
[ 3.704902] ESR = 0x96000005
[ 3.704905] EC = 0x25: DABT (current EL), IL = 32 bits
[ 3.704907] SET = 0, FnV = 0
[ 3.704912] EA = 0, S1PTW = 0
[ 3.713800] ahci-ceva fd0c0000.ahci: supply ahci not found, using dummy regulator
[ 3.715585] Data abort info:
[ 3.715587] ISV = 0, ISS = 0x00000005
[ 3.715589] CM = 0, WnR = 0
[ 3.715592] [000000000000012c] user address but active_mm is swapper
[ 3.715596] Internal error: Oops: 96000005 [#1] SMP
[ 3.715599] Modules linked in:
[ 3.715608] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.10.0-12170-g60894882155f-dirty #77
[ 3.723937] Hardware name: ZynqMP ZCU102 Rev1.0 (DT)
[ 3.723942] pstate: 80000085 (Nzcv daIf -PAN -UAO -TCO BTYPE=--)
[ 3.723956] pc : xilinx_dpdma_irq_handler+0x418/0x560
[ 3.793049] lr : xilinx_dpdma_irq_handler+0x3d8/0x560
[ 3.798089] sp : ffffffc01186bdf0
[ 3.801388] x29: ffffffc01186bdf0 x28: ffffffc011836f28
[ 3.806692] x27: ffffff8023e0ac80 x26: 0000000000000080
[ 3.811996] x25: 0000000008000408 x24: 0000000000000003
[ 3.817300] x23: ffffffc01186be70 x22: ffffffc011291740
[ 3.822604] x21: 0000000000000000 x20: 0000000008000408
[ 3.827908] x19: 0000000000000000 x18: 0000000000000010
[ 3.833212] x17: 0000000000000000 x16: 0000000000000000
[ 3.838516] x15: 0000000000000000 x14: ffffffc011291740
[ 3.843820] x13: ffffffc02eb4d000 x12: 0000000034d4d91d
[ 3.849124] x11: 0000000000000040 x10: ffffffc0112d2d48
[ 3.854428] x9 : ffffffc0112d2d40 x8 : ffffff8021c00268
[ 3.859732] x7 : 0000000000000000 x6 : ffffffc011836000
[ 3.865036] x5 : 0000000000000003 x4 : 0000000000000000
[ 3.870340] x3 : 0000000000000001 x2 : 0000000000000000
[ 3.875644] x1 : 0000000000000000 x0 : 000000000000012c
[ 3.880948] Call trace:
[ 3.883382] xilinx_dpdma_irq_handler+0x418/0x560
[ 3.888079] __handle_irq_event_percpu+0x5c/0x178
[ 3.892774] handle_irq_event_percpu+0x34/0x98
[ 3.897210] handle_irq_event+0x44/0xb8
[ 3.901030] handle_fasteoi_irq+0xd0/0x190
[ 3.905117] generic_handle_irq+0x30/0x48
[ 3.909111] __handle_domain_irq+0x64/0xc0
[ 3.913192] gic_handle_irq+0x78/0xa0
[ 3.916846] el1_irq+0xc4/0x180
[ 3.919982] cpuidle_enter_state+0x134/0x2f8
[ 3.924243] cpuidle_enter+0x38/0x50
[ 3.927810] call_cpuidle+0x1c/0x40
[ 3.931290] do_idle+0x20c/0x270
[ 3.934502] cpu_startup_entry+0x28/0x58
[ 3.938410] rest_init+0xbc/0xcc
[ 3.941631] arch_call_rest_init+0x10/0x1c
[ 3.945718] start_kernel+0x51c/0x558

Fixes: 7cbb0c63de3f ("dmaengine: xilinx: dpdma: Add the Xilinx DisplayPort DMA engine driver")
Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com>
Link: https://lore.kernel.org/r/20210430064041.4058180-1-quanyang.wang@windriver.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/dma/xilinx/xilinx_dpdma.c | 24 +++++++++++++++++++++++-
1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/xilinx/xilinx_dpdma.c b/drivers/dma/xilinx/xilinx_dpdma.c
index 70b29bd079c9..ff7dfb3fdeb4 100644
--- a/drivers/dma/xilinx/xilinx_dpdma.c
+++ b/drivers/dma/xilinx/xilinx_dpdma.c
@@ -1459,7 +1459,7 @@ static void xilinx_dpdma_enable_irq(struct xilinx_dpdma_device *xdev)
*/
static void xilinx_dpdma_disable_irq(struct xilinx_dpdma_device *xdev)
{
- dpdma_write(xdev->reg, XILINX_DPDMA_IDS, XILINX_DPDMA_INTR_ERR_ALL);
+ dpdma_write(xdev->reg, XILINX_DPDMA_IDS, XILINX_DPDMA_INTR_ALL);
dpdma_write(xdev->reg, XILINX_DPDMA_EIDS, XILINX_DPDMA_EINTR_ALL);
}

@@ -1596,6 +1596,26 @@ static struct dma_chan *of_dma_xilinx_xlate(struct of_phandle_args *dma_spec,
return dma_get_slave_channel(&xdev->chan[chan_id]->vchan.chan);
}

+static void dpdma_hw_init(struct xilinx_dpdma_device *xdev)
+{
+ unsigned int i;
+ void __iomem *reg;
+
+ /* Disable all interrupts */
+ xilinx_dpdma_disable_irq(xdev);
+
+ /* Stop all channels */
+ for (i = 0; i < ARRAY_SIZE(xdev->chan); i++) {
+ reg = xdev->reg + XILINX_DPDMA_CH_BASE
+ + XILINX_DPDMA_CH_OFFSET * i;
+ dpdma_clr(reg, XILINX_DPDMA_CH_CNTL, XILINX_DPDMA_CH_CNTL_ENABLE);
+ }
+
+ /* Clear the interrupt status registers */
+ dpdma_write(xdev->reg, XILINX_DPDMA_ISR, XILINX_DPDMA_INTR_ALL);
+ dpdma_write(xdev->reg, XILINX_DPDMA_EISR, XILINX_DPDMA_EINTR_ALL);
+}
+
static int xilinx_dpdma_probe(struct platform_device *pdev)
{
struct xilinx_dpdma_device *xdev;
@@ -1622,6 +1642,8 @@ static int xilinx_dpdma_probe(struct platform_device *pdev)
if (IS_ERR(xdev->reg))
return PTR_ERR(xdev->reg);

+ dpdma_hw_init(xdev);
+
xdev->irq = platform_get_irq(pdev, 0);
if (xdev->irq < 0) {
dev_err(xdev->dev, "failed to get platform irq\n");
--
2.30.2