PL330: Add PL330 DMA controller driver
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From: jassi brar on 25 Mar 2010 01:40 On Thu, Mar 25, 2010 at 12:17 PM, Joonyoung Shim <jy0922.shim(a)samsung.com> wrote: > The PL330 is currently the dma controller using at the S5PC1XX arm SoC. > This supports DMA_MEMCPY and DMA_SLAVE. > > The datasheet for the PL330 can find below url: > http://infocenter.arm.com/help/topic/com.arm.doc.ddi0424a/DDI0424A_dmac_pl330_r0p0_trm.pdf > > Signed-off-by: Joonyoung Shim <jy0922.shim(a)samsung.com> > --- > Change log: > > v2: Convert into an amba_device driver. > Code clean and update from v1 patch review. [CC'ing Russell and Ben as stakeholders] Dear Maintainers I too have been writing a driver for PL330 after taking into account the suggestions of Russell, Ben and other participants of the thread http://lists.infradead.org/pipermail/linux-arm-kernel/2010-February/009856.html If you don't think this driver conflicts with the theme of the thread, may I ask you to please put this driver on hold until you checkout my implementation of solution to the issue... which should be soon. Regards, Jaswinder Singh Solution-1 Group Linux Kernel Team System LSI Division Samsung Electronics Co., Ltd. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Marc Zyngier on 25 Mar 2010 01:50 On Thu, 25 Mar 2010 12:17:15 +0900 Joonyoung Shim <jy0922.shim(a)samsung.com> wrote: > +/* instruction set functions */ > +static inline int pl330_dmaaddh(u8 *desc_pool_virt, u16 imm, bool ra) > +{ > + u8 opcode = DMAADDH | (ra << 1); > + > + writeb(opcode, desc_pool_virt++); desc_pool_virt is a virtual address (from dma_alloc_coherent). In such case, write[bwl] seems to be the wrong interface. I suggest the following code: *desc_pool_virt++ = opcode; > + writew(imm, desc_pool_virt); Does anything ensure that this won't generate an unaligned access? > + return 3; > +} M. -- I'm the slime oozin' out from your TV set... -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Linus Walleij on 25 Mar 2010 04:30 2010/3/25 Joonyoung Shim <jy0922.shim(a)samsung.com>: > The PL330 is currently the dma controller using at the S5PC1XX arm SoC. > This supports DMA_MEMCPY and DMA_SLAVE. Looks good to me now so: Acked-by: Linus Walleij <linus.walleij(a)stericsson.com> Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Linus Walleij on 25 Mar 2010 04:40 2010/3/25 jassi brar <jassisinghbrar(a)gmail.com>: > I too have been writing a driver for PL330 after taking into account the > suggestions of Russell, Ben and other participants of the thread > http://lists.infradead.org/pipermail/linux-arm-kernel/2010-February/009856.html > > If you don't think this driver conflicts with the theme of the thread, > may I ask you to please put this driver on hold until you checkout my implementation > of solution to the issue... which should be soon. Please post the code as it looks today even if it's not compiling instead of asking others to hold their patches back. It will be obvious from what you have if there is some special use you're covering. Perhaps Joonyoung can simply port over the stuff you need to this driver if you show your code. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Joonyoung Shim on 25 Mar 2010 05:10
On 3/25/2010 2:44 PM, Marc Zyngier wrote: > On Thu, 25 Mar 2010 12:17:15 +0900 > Joonyoung Shim <jy0922.shim(a)samsung.com> wrote: > >> +/* instruction set functions */ >> +static inline int pl330_dmaaddh(u8 *desc_pool_virt, u16 imm, bool ra) >> +{ >> + u8 opcode = DMAADDH | (ra << 1); >> + >> + writeb(opcode, desc_pool_virt++); > > desc_pool_virt is a virtual address (from dma_alloc_coherent). In such > case, write[bwl] seems to be the wrong interface. I suggest the > following code: > > *desc_pool_virt++ = opcode; > >> + writew(imm, desc_pool_virt); > Right. The write[bwl] is api for address ioremapped of io device. I will change these. > Does anything ensure that this won't generate an unaligned access? > PL330 DMA controller fetches variable length instructions that consist of one to six bytes, so i think unaligned access is no problem. >> + return 3; >> +} > > M. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |