Hi Anurag, On Wednesday 23 Sep 2015 15:12:36 Anurag Kumar Vulisha wrote: > On Monday, September 21, 2015 9:27 PM Vinod Koul wrote: > > On Thu, Aug 27, 2015 at 09:19:18PM +0530, Anurag Kumar Vulisha wrote: > >> This VDMA is a soft ip, which can be programmed to support > >> 32 bit addressing or greater than 32 bit addressing. > >> > >> When the VDMA ip is configured for 32 bit address space the transfer > >> start address is specified by a single register. > > > > would be good to specfiy which one > > Will change this in v3 What happened to v3 ? :-) > >> When the VDMA core is configured for an address space greater than 32 > >> then each start address is specified by a combination of two > >> registers. The first register specifies the LSB 32 bits of address, > >> while the next register specifies the MSB 32 bits of address.For > >> example,5Ch will specify the LSB 32 bits while 60h will specify the > >> MSB 32 bits of the first start address.So we need to program two > >> registers at a time. > > > > can we have spaces after full stops and commas! > > Will take care of this in v3 patch. > > >> +/* Since vdma driver is trying to write to a register offset which is > >> +not a > >> + * multiple of 64 bits(ex : 0x5c), we are writing as two separate 32 > >> +bits > >> + * instead of a single 64 bit register write. > >> + */ > > > > This is not kernel style for multi-lines, pls refer to > > Documentation/CodingStyle > > Will address this in v3 patch > > >> + > >> +static inline void vdma_desc_write_64(struct xilinx_vdma_chan *chan, > >> u32 reg, > >> + u32 value_lsb, u32 value_msb) > >> +{ > >> + /* Write the lsb 32 bits*/ > >> + writel(value_lsb, chan->xdev->regs + chan->desc_offset + reg); > >> + > >> + /* Write the msb 32 bits */ > >> + writel(value_msb, chan->xdev->regs + chan->desc_offset + reg + 4); > > > > why not writeq > > We are trying to write at a register address(ex:0x5c) which is not aligned > on 8 bytes boundary.So if I try to use 64 bit write on it,unalignment > fault is getting generated.To avoid that we are using two separate 32 bit > writes. We had this discussion in previous versions of this patch with > Laurent Pinchart .I have also added this exaplanation in the comments above > this function. > > >> + err = of_property_read_u32(node, "xlnx,addrwidth", &addr_width); > >> + > >> + if (err < 0) { > >> + /* Setting addr_width property to default 32 bits */ > >> + addr_width = 32; > >> + } > > > > braces for a single line statement! Also space is redandant before if > > condition > > Will take care of this in v3 patch -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html