MUSB RTL version 1.8 onward (OMAP3630, AM/DM37x, OMAP4) DMA requires
the buffers to be aligned on a four byte boundary. This affects USB
CDC/RNDIS class application where buffers are always unaligned.
Use system DMA for unaligned buffers as a workaround of this issue.
Current patch supports device side CDC/RNDIS. Host side would require
change in Tx programming path for mode-0 operation when transfer length
is more than packet size.
Also fixed an issue in device Tx completion path where 'is_dma' is getting
set unconditionally. This would fail the io if Tx transfer is done in
mode-0. Fixed it by updating it based on 'request->actual' length.
Signed-off-by: Ajay Kumar Gupta <ajay.gupta@xxxxxx>
---
drivers/usb/musb/Kconfig | 6 +++
drivers/usb/musb/musb_gadget.c | 21 +++++++++++-
drivers/usb/musb/musbhsdma.c | 75 ++++++++++++++++++++++++++++++++++++++--
3 files changed, 98 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/musb/Kconfig b/drivers/usb/musb/Kconfig
index f847fe2..05db0ff 100644
--- a/drivers/usb/musb/Kconfig
+++ b/drivers/usb/musb/Kconfig
@@ -166,6 +166,12 @@ config MUSB_USE_SYSTEM_DMA_WORKAROUND
DMA channels are simultaneously enabled. To work around this issue,
you can choose to use System DMA for RX channels.
+ Also on Mentor DMA in MUSB RTL version 1.8 (OMAP3630, AM/DM37x)
+ requires buffers to be aligned on a four byte boundary. This affects
+ USB CDC/RNDIS class application where buffers are always unaligned.
+ To work around this issue, you can choose to use System DMA for
+ unaligned buffers.
+
config USB_TI_CPPI_DMA
bool
depends on USB_MUSB_HDRC && !MUSB_PIO_ONLY
diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
index 6fca870..9ac45e4 100644
--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -317,6 +317,22 @@ static void txstate(struct musb *musb, struct musb_request *req)
else
musb_ep->dma->desired_mode = 1;
+ /*
+ * Use system dma for unaligned buffers on RTL >= 1.8
+ * for Inventra DMA. As system DMA can work only in
+ * mode-0 so update the desired_mode and request_size.
+ */
+ if (is_inventra_dma_enabled() &&
+ ((request->dma + request->actual) & 0x3) &&
+ (musb->hwvers >= MUSB_HWVERS_1800)) {
+
+ request_size = min_t(size_t,
+ musb_ep->hw_ep->max_packet_sz_tx,
+ request->length - request->actual);
+
+ musb_ep->dma->desired_mode = 0;
+ }
+
use_dma = use_dma && c->channel_program(
musb_ep->dma, musb_ep->packet_sz,
musb_ep->dma->desired_mode,
@@ -463,7 +479,6 @@ void musb_g_tx(struct musb *musb, u8 epnum)
u8 is_dma = 0;
if (dma && (csr & MUSB_TXCSR_DMAENAB)) {
- is_dma = 1;
csr |= MUSB_TXCSR_P_WZC_BITS;
csr &= ~(MUSB_TXCSR_DMAENAB | MUSB_TXCSR_P_UNDERRUN |
MUSB_TXCSR_TXPKTRDY);
@@ -471,6 +486,10 @@ void musb_g_tx(struct musb *musb, u8 epnum)
/* Ensure writebuffer is empty. */
csr = musb_readw(epio, MUSB_TXCSR);
request->actual += musb_ep->dma->actual_len;
+
+ if (request->actual == request->length)
+ is_dma = 1;
+
DBG(4, "TXCSR%d %04x, DMA off, len %zu, req %p\n",
epnum, csr, musb_ep->dma->actual_len, request);
}
diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
index 70342eb..6118d5f 100644
--- a/drivers/usb/musb/musbhsdma.c
+++ b/drivers/usb/musb/musbhsdma.c
@@ -54,12 +54,18 @@ static void musb_sysdma_completion(int lch, u16 ch_status, void *data)
(struct musb_dma_channel *) data;
struct musb_dma_controller *controller = musb_channel->controller;
struct musb *musb = controller->private_data;
+ void __iomem *mbase = controller->base;
+
channel = &musb_channel->channel;
DBG(2, "lch = 0x%d, ch_status = 0x%x\n", lch, ch_status);
spin_lock_irqsave(&musb->lock, flags);
- addr = (u32) omap_get_dma_dst_pos(musb_channel->sysdma_channel);
+ if (musb_channel->transmit)
+ addr = (u32) omap_get_dma_src_pos(musb_channel->sysdma_channel);
+ else
+ addr = (u32) omap_get_dma_dst_pos(musb_channel->sysdma_channel);
+
if (musb_channel->len == 0)
channel->actual_len = 0;
else
@@ -72,6 +78,26 @@ static void musb_sysdma_completion(int lch, u16 ch_status, void *data)
"=> reconfig 0 " : " => complete");
channel->status = MUSB_DMA_STATUS_FREE;
+
+ /* completed */
+ if ((musb_channel->transmit) && (channel->desired_mode == 0)
+ && (channel->actual_len == musb_channel->max_packet_sz)) {
+
+ u8 epnum = musb_channel->epnum;
+ int offset = MUSB_EP_OFFSET(epnum,
+ MUSB_TXCSR);
+ u16 txcsr;
+
+ /*
+ * The programming guide says that we
+ * must clear DMAENAB before DMAMODE.
+ */
+ musb_ep_select(mbase, epnum);
+ txcsr = musb_readw(mbase, offset);
+ txcsr |= MUSB_TXCSR_TXPKTRDY;
+ musb_writew(mbase, offset, txcsr);
+ }
+
musb_dma_completion(musb, musb_channel->epnum, musb_channel->transmit);
spin_unlock_irqrestore(&musb->lock, flags);
@@ -138,8 +164,15 @@ static struct dma_channel *dma_channel_allocate(struct dma_controller *c,
* issue when TX and RX DMA channels are simultaneously
* enabled. To work around this issue, use system DMA
* for all RX channels.
+ * Also on MUSB RTL version 1.8 onward (OMAP3630, OMAP4
+ * and AM/DM37x) DMA requires buffers to be aligned on
+ * a four byte boundary. This affects USB CDC/RNDIS
+ * class application where buffers are always unaligned.
+ * Using system DMA for unaligned buffers as a
+ * workaround for this issue.
*/
- if (((musb->hwvers == MUSB_HWVERS_1400) && !transmit)
+ if ((((musb->hwvers == MUSB_HWVERS_1400) && !transmit)
+ || (musb->hwvers >= MUSB_HWVERS_1800))
&& use_sdma_workaround()) {
int ret;
ret = omap_request_dma(OMAP24XX_DMA_NO_DEVICE,
@@ -194,11 +227,18 @@ static void configure_channel(struct dma_channel *channel,
struct musb *musb = controller->private_data;
void __iomem *mbase = controller->base;
u8 bchannel = musb_channel->idx;
+ u8 buffer_is_aligned = (dma_addr & 0x3) ? 0 : 1;
+ u8 use_sdma = (musb_channel->sysdma_channel == -1) ? 0 : 1;
u16 csr = 0;
DBG(4, "%p, pkt_sz %d, addr 0x%x, len %d, mode %d\n",
channel, packet_sz, dma_addr, len, mode);
- if (musb_channel->sysdma_channel != -1) {
+
+ if (buffer_is_aligned && (packet_sz >= 512) &&
+ (musb->hwvers >= MUSB_HWVERS_1800))
+ use_sdma = 0;
+
+ if (use_sdma && !musb_channel->transmit) {
/* System DMA */
/* RX: set src = FIFO */
omap_set_dma_transfer_params(musb_channel->sysdma_channel,
@@ -224,6 +264,32 @@ static void configure_channel(struct dma_channel *channel,
omap_start_dma(musb_channel->sysdma_channel);
+ } else if (use_sdma && musb_channel->transmit) {
+ /* System DMA */
+ /* TX: set dst = FIFO */
+ omap_set_dma_transfer_params(musb_channel->sysdma_channel,
+ OMAP_DMA_DATA_TYPE_S8,
+ len ? len : 1, 1, /* One frame */
+ OMAP_DMA_SYNC_ELEMENT,
+ OMAP24XX_DMA_NO_DEVICE,
+ 0); /* Src Sync */
+
+ omap_set_dma_src_params(musb_channel->sysdma_channel, 0,
+ OMAP_DMA_AMODE_POST_INC, dma_addr,
+ 0, 0);
+
+ omap_set_dma_dest_params(musb_channel->sysdma_channel, 0,
+ OMAP_DMA_AMODE_CONSTANT,
+ MUSB_FIFO_ADDRESS(musb->ctrl_phys_base,
+ musb_channel->epnum),
+ 0, 0);
+
+ omap_set_dma_dest_data_pack(musb_channel->sysdma_channel, 0);
+ omap_set_dma_dest_burst_mode(musb_channel->sysdma_channel,
+ OMAP_DMA_DATA_BURST_DIS);
+
+ omap_start_dma(musb_channel->sysdma_channel);
+
} else { /* Mentor DMA */
if (mode) {
@@ -299,6 +365,9 @@ static int dma_channel_abort(struct dma_channel *channel)
if (channel->status == MUSB_DMA_STATUS_BUSY) {
if (musb_channel->transmit) {
+ if (musb_channel->sysdma_channel != -1)
+ omap_stop_dma(musb_channel->sysdma_channel);
+
offset = MUSB_EP_OFFSET(musb_channel->epnum,
MUSB_TXCSR);
--
1.6.2.4
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