From: Hema HK <hemahk@xxxxxx>
Dma channels are allocated in musb_gadget_enable function.
Mentor has only 8 dma channels against 31 endpoints.If there are
multiple gadgets(g_multi) using multiple endpoints enable the endpoints
but not doing the data trasnfers,then other endpoints endup using PIO mode.
The effective utilization of DMA channels will be done by allocating
the dma channels during data transfer request and releasing when the
request completes.
Signed-off-by: Hema HK <hemahk@xxxxxx>
Cc: Felipe Balbi <felipe.balbi@xxxxxxxxx>
---
Based off V2.6.34 + gregkh-07-usb-2.6.34.patch
[Rebased with "[PATCH v6] usb: musb: Unmapping the dma buffer when switching to PIO mode" ]
Index: linux-2.6/drivers/usb/musb/musb_gadget.c
===================================================================
--- linux-2.6.orig/drivers/usb/musb/musb_gadget.c
+++ linux-2.6/drivers/usb/musb/musb_gadget.c
@@ -122,23 +122,25 @@ static inline void map_dma_buffer(struct
static inline void unmap_dma_buffer(struct musb_request *request,
struct musb *musb)
{
- if (request->mapped) {
- dma_unmap_single(musb->controller,
- request->request.dma,
- request->request.length,
- request->tx
- ? DMA_TO_DEVICE
- : DMA_FROM_DEVICE);
- request->request.dma = DMA_ADDR_INVALID;
- request->mapped = 0;
- } else {
- dma_sync_single_for_cpu(musb->controller,
- request->request.dma,
- request->request.length,
- request->tx
- ? DMA_TO_DEVICE
- : DMA_FROM_DEVICE);
+ if (request->request.dma != DMA_ADDR_INVALID) {
+ if (request->mapped) {
+ dma_unmap_single(musb->controller,
+ request->request.dma,
+ request->request.length,
+ request->tx
+ ? DMA_TO_DEVICE
+ : DMA_FROM_DEVICE);
+ request->request.dma = DMA_ADDR_INVALID;
+ request->mapped = 0;
+ } else {
+ dma_sync_single_for_cpu(musb->controller,
+ request->request.dma,
+ request->request.length,
+ request->tx
+ ? DMA_TO_DEVICE
+ : DMA_FROM_DEVICE);
+ }
}
}
@@ -169,8 +171,12 @@ __acquires(ep->musb->lock)
ep->busy = 1;
spin_unlock(&musb->lock);
- if (is_dma_capable() && ep->dma)
+ if (is_dma_capable() && ep->dma) {
+ struct dma_controller *c = ep->musb->dma_controller;
+ c->channel_release(ep->dma);
+ ep->dma = NULL;
unmap_dma_buffer(req, musb);
+ }
if (request->status == 0)
DBG(5, "%s done request %p, %d/%d\n",
ep->end_point.name, request,
@@ -294,14 +300,12 @@ static inline int max_ep_writesize(struc
static void txstate(struct musb *musb, struct musb_request *req)
{
u8 epnum = req->epnum;
- struct musb_ep *musb_ep;
+ struct musb_ep *musb_ep = req->ep;
void __iomem *epio = musb->endpoints[epnum].regs;
struct usb_request *request;
u16 fifo_count = 0, csr;
int use_dma = 0;
-
- musb_ep = req->ep;
-
+ struct musb_hw_ep *hw_ep = musb_ep->hw_ep;
/* we shouldn't get here while DMA is active ... but we do ... */
if (dma_channel_status(musb_ep->dma) == MUSB_DMA_STATUS_BUSY) {
DBG(4, "dma pending...\n");
@@ -332,9 +336,24 @@ static void txstate(struct musb *musb, s
csr);
#ifndef CONFIG_MUSB_PIO_ONLY
- if (is_dma_capable() && musb_ep->dma) {
- struct dma_controller *c = musb->dma_controller;
+ struct dma_controller *c = musb->dma_controller;
+ if (is_cppi_enabled() && !musb_ep->dma) {
+
+ /*
+ * allocate dma channel if not allocated
+ * for this endpoint already
+ */
+ musb_ep->dma = c->channel_alloc(c, hw_ep, musb_ep->is_in);
+ /*
+ * channel allocation is successfull now map the
+ * buffer to dma configure the DMA channel for
+ * recieving the packets
+ */
+ if (musb_ep->dma)
+ map_dma_buffer(req, musb);
+ }
+ if (musb_ep->dma) {
use_dma = (request->dma != DMA_ADDR_INVALID);
/* MUSB_TXCSR_P_ISO is still set correctly */
@@ -615,6 +634,7 @@ static void rxstate(struct musb *musb, s
u16 len = musb_ep->packet_sz;
u16 csr = musb_readw(epio, MUSB_RXCSR);
+ struct musb_hw_ep *hw_ep = musb_ep->hw_ep;
/* We shouldn't get here while DMA is active, but we do... */
if (dma_channel_status(musb_ep->dma) == MUSB_DMA_STATUS_BUSY) {
DBG(4, "DMA pending...\n");
@@ -627,6 +647,21 @@ static void rxstate(struct musb *musb, s
return;
}
+ if (is_dma_capable() && !musb_ep->dma) {
+ struct dma_controller *c = musb->dma_controller;
+ /*
+ * Allocate dma channel if not allocated
+ * for this endpoint already
+ */
+ musb_ep->dma = c->channel_alloc(c, hw_ep, musb_ep->is_in);
+ /*
+ * Channel allocation is successfull now map the buffer
+ * to dma configure the DMA channel for recieving the
+ * packets
+ */
+ if (musb_ep->dma)
+ map_dma_buffer(req, musb);
+ }
if (is_cppi_enabled() && musb_ep->dma) {
struct dma_controller *c = musb->dma_controller;
struct dma_channel *channel = musb_ep->dma;
@@ -642,9 +677,10 @@ static void rxstate(struct musb *musb, s
request->dma + request->actual,
request->length - request->actual)) {
- /* make sure that if an rxpkt arrived after the irq,
- * the cppi engine will be ready to take it as soon
- * as DMA is enabled
+ /*
+ * Make sure that if an rxpkt arrived after the
+ * irq,the cppi engine will be ready to take it
+ * as soon as DMA is enabled
*/
csr &= ~(MUSB_RXCSR_AUTOCLEAR
| MUSB_RXCSR_DMAMODE);
@@ -1010,20 +1046,13 @@ static int musb_gadget_enable(struct usb
/* NOTE: all the I/O code _should_ work fine without DMA, in case
* for some reason you run out of channels here.
*/
- if (is_dma_capable() && musb->dma_controller) {
- struct dma_controller *c = musb->dma_controller;
-
- musb_ep->dma = c->channel_alloc(c, hw_ep,
- (desc->bEndpointAddress & USB_DIR_IN));
- } else
- musb_ep->dma = NULL;
musb_ep->desc = desc;
musb_ep->busy = 0;
musb_ep->wedged = 0;
status = 0;
- pr_debug("%s periph: enabled %s for %s %s, %smaxpacket %d\n",
+ pr_debug("%s periph: enabled %s for %s %s, maxpacket %d\n",
musb_driver_name, musb_ep->end_point.name,
({ char *s; switch (musb_ep->type) {
case USB_ENDPOINT_XFER_BULK: s = "bulk"; break;
@@ -1031,7 +1060,6 @@ static int musb_gadget_enable(struct usb
default: s = "iso"; break;
}; s; }),
musb_ep->is_in ? "IN" : "OUT",
- musb_ep->dma ? "dma, " : "",
musb_ep->packet_sz);
schedule_work(&musb->irq_work);
@@ -1173,13 +1201,8 @@ static int musb_gadget_queue(struct usb_
request->epnum = musb_ep->current_epnum;
request->tx = musb_ep->is_in;
- if (is_dma_capable() && musb_ep->dma)
- map_dma_buffer(request, musb);
- else if (!req->buf)
+ if (!req->buf)
return -ENODATA;
- else
- request->mapped = 0;
-
spin_lock_irqsave(&musb->lock, lockflags);
/* don't queue if the ep is down */
--
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