From c8ebae37034c0ead62eb4df8ef88e999ddb8d5cf Mon Sep 17 00:00:00 2001 From: Russell King Date: Tue, 11 Jan 2011 19:35:53 +0000 Subject: ARM: mmci: add dmaengine-based DMA support Based on a patch from Linus Walleij. Add dmaengine based support for DMA to the MMCI driver, using the Primecell DMA engine interface. The changes over Linus' driver are: - rename txsize_threshold to dmasize_threshold, as this reflects the purpose more. - use 'mmci_dma_' as the function prefix rather than 'dma_mmci_'. - clean up requesting of dma channels. - don't release a single channel twice when it's shared between tx and rx. - get rid of 'dma_enable' bool - instead check whether the channel is NULL. - detect incomplete DMA at the end of a transfer. Some DMA controllers (eg, PL08x) are unable to be configured for scatter DMA and also listen to all four DMA request signals [BREQ,SREQ,LBREQ,LSREQ] from the MMCI. They can do one or other but not both. As MMCI uses LBREQ/LSREQ for the final burst/words, PL08x does not transfer the last few words. - map and unmap DMA buffers using the DMA engine struct device, not the MMCI struct device - the DMA engine is doing the DMA transfer, not us. - avoid double-unmapping of the DMA buffers on MMCI data errors. - don't check for negative values from the dmaengine tx submission function - Dan says this must never fail. - use new dmaengine helper functions rather than using the ugly function pointers directly. - allow DMA code to be fully optimized away using dma_inprogress() which is defined to constant 0 if DMA engine support is disabled. - request maximum segment size from the DMA engine struct device and set this appropriately. - removed checking of buffer alignment - the DMA engine should deal with its own restrictions on buffer alignment, not the individual DMA engine users. - removed setting DMAREQCTL - this confuses some DMA controllers as it causes LBREQ to be asserted for the last seven transfers, rather than six SREQ and one LSREQ. - removed burst setting - the DMA controller should not burst past the transfer size required to complete the DMA operation. Tested-by: Linus Walleij Signed-off-by: Russell King --- drivers/mmc/host/mmci.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'drivers/mmc/host/mmci.h') diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h index 164ce060fc1f..ec9a7bc6d0df 100644 --- a/drivers/mmc/host/mmci.h +++ b/drivers/mmc/host/mmci.h @@ -148,8 +148,10 @@ struct clk; struct variant_data; +struct dma_chan; struct mmci_host { + phys_addr_t phybase; void __iomem *base; struct mmc_request *mrq; struct mmc_command *cmd; @@ -179,5 +181,16 @@ struct mmci_host { struct sg_mapping_iter sg_miter; unsigned int size; struct regulator *vcc; + +#ifdef CONFIG_DMA_ENGINE + /* DMA stuff */ + struct dma_chan *dma_current; + struct dma_chan *dma_rx_channel; + struct dma_chan *dma_tx_channel; + +#define dma_inprogress(host) ((host)->dma_current) +#else +#define dma_inprogress(host) (0) +#endif }; -- cgit v1.2.3