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path: root/drivers/dma/sh/rcar-dmac.c
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2015-02-12dmaengine: rcar-dmac: Fix uninitialized variable usageLaurent Pinchart
The desc variable is used uninitialized in the rcar_dmac_desc_get() and rcar_dmac_xfer_chunk_get() functions if descriptors need to be allocated. Fix it. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-12-23dmaengine: rcar-dmac: Handle hardware descriptor allocation failureJürg Billeter
If the atomic DMA coherent pool is too small, disable use of hardware descriptor lists instead of crashing the system: ERROR: 256 KiB atomic DMA coherent pool is too small! Please increase it with coherent_pool= kernel parameter! Unable to handle kernel NULL pointer dereference at virtual address 00000004 Internal error: Oops: a07 [#1] PREEMPT SMP ARM PC is at rcar_dmac_chan_reinit+0x3c/0x160 LR is at _raw_spin_lock_irqsave+0x18/0x5c [<802132c0>] (rcar_dmac_chan_reinit) from [<80214818>] (rcar_dmac_isr_error+0x84/0xa0) [<80214818>] (rcar_dmac_isr_error) from [<80060484>] (handle_irq_event_percpu+0x50/0x150) [<80060484>] (handle_irq_event_percpu) from [<800605c0>] (handle_irq_event+0x3c/0x5c) [<800605c0>] (handle_irq_event) from [<8006350c>] (handle_fasteoi_irq+0xb8/0x198) [<8006350c>] (handle_fasteoi_irq) from [<8005fdb0>] (generic_handle_irq+0x20/0x30) [<8005fdb0>] (generic_handle_irq) from [<8000fcd0>] (handle_IRQ+0x50/0xc4) [<8000fcd0>] (handle_IRQ) from [<800092cc>] (gic_handle_irq+0x28/0x5c) [<800092cc>] (gic_handle_irq) from [<80012700>] (__irq_svc+0x40/0x70) Kernel panic - not syncing: Fatal exception in interrupt Signed-off-by: Jürg Billeter <j@bitron.ch> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
2014-12-23dmaengine: rcar-dmac: Cache hardware descriptors memoryLaurent Pinchart
Unlike DMA transfers descriptors that are preallocated and cached, memory used to store hardware descriptors is allocated and freed with the DMA coherent allocation API for every transfer. Besides degrading performances, this creates a CMA stress test that seems to cause issues. Running dmatest with the noverify option produces [ 50.066539] alloc_contig_range test_pages_isolated(6b845, 6b846) failed [ 50.235180] alloc_contig_range test_pages_isolated(6b848, 6b84e) failed [ 52.964584] alloc_contig_range test_pages_isolated(6b847, 6b848) failed [ 54.127113] alloc_contig_range test_pages_isolated(6b843, 6b844) failed [ 56.270253] alloc_contig_range test_pages_isolated(6b84c, 6b850) failed The root cause needs to be fixed, but in the meantime, as a workaround and a performance improvement, cache hardware descriptors. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
2014-12-23dmaengine: rcar-dmac: Implement support for hardware descriptor listsLaurent Pinchart
The DMAC supports hardware-based auto-configuration from descriptor lists. This reduces the number of interrupts required for processing a DMA transfer. Support that mode in the driver. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
2014-12-23dmaengine: rcar-dmac: Add Renesas R-Car Gen2 DMA Controller (DMAC) driverLaurent Pinchart
The DMAC is a general purpose multi-channel DMA controller that supports both slave and memcpy transfers. The driver currently supports the DMAC found in the r8a7790 and r8a7791 SoCs. Support for compatible DMA controllers (such as the audio DMAC) will be added later. Feature-wise, automatic hardware handling of descriptors chains isn't supported yet. LPAE support is implemented. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Tested-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>