Does your solution supports mixing of DMA and PIO? The MUSB DMA doesn't support odd number of bytes or mixing 1/2/4 byte access. So, we will need mixing of DMA and PIO mode for transfer. There is a need to add the cache flush/invalidate code by default when switching between PIO and DMA mode. The cache flush/invalidate code needs to be added in the generic code as it already knows if a chain is setup using DMA or not. > -----Original Message----- > From: Pandita, Vikram [mailto:vikram.pandita@xxxxxx] > Sent: Wednesday, August 04, 2010 10:28 PM > To: Gadiyar, Anand; linux-usb@xxxxxxxxxxxxxxx > Cc: Mankad, Maulik Ojas; Shilimkar, Santosh; Oliver Neukum; Alan Stern; Praveena NADAHALLY; Felipe Balbi; Gupta, Ajay Kumar > Subject: RE: [PATCH v3] usb: musb: do not use dma for control transfers > > > >>-----Original Message----- >>From: linux-usb-owner@xxxxxxxxxxxxxxx [mailto:linux-usb- >>owner@xxxxxxxxxxxxxxx] On Behalf Of Gadiyar, Anand > <snip> >>Index: kernel-omap4-base/include/linux/usb.h >>=================================================================== >>--- kernel-omap4-base.orig/include/linux/usb.h 2010-08-04 >>14:57:04.109948812 +0530 >>+++ kernel-omap4-base/include/linux/usb.h 2010-08-04 14:58:20.817938610 >>+0530 >>@@ -311,6 +311,10 @@ >> int busnum; /* Bus number (in order of reg) */ >> const char *bus_name; /* stable id (PCI slot_name etc) */ >> u8 uses_dma; /* Does the host controller use DMA? */ >>+ u8 uses_pio_for_control; /* >>+ * Does the host controller use PIO >>+ * for control transfers? >>+ */ > > Wondering we already have uses_dma an 8-bit flag available. > Is it wise to use the uses_dma flag as a bit mask to show DMA properties > and avoid adding additional u8? > > Something like: > DMA_NONE (0) > DMA_ENABLE_BULK (1<0) > DMA_ENABLE_CONTROL (1<1) > > So that if (uses_dma) still continues to work > And anyone having a need or CONTROL DMA can check explicitly... > >> u8 otg_port; /* 0, or number of OTG/HNP port */ >> unsigned is_b_host:1; /* true during some HNP roleswitches */ >> unsigned b_hnp_enable:1; /* OTG: did A-Host enable HNP? */ > <snip> > -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
