At least with the cppi41 dma, size 1 in dma transfers will just wait
until the device is disconnected. This causes timeouts in cppi41 dma
runtime PM.
Also the initial size 8 transfers take about 200ms to complete when
plugging a USB mass storage device to a hub. But we probably want to
keep those to avoid using PIO.
Fix the issue by adding a quirk for cppi41 and skip size 1 in dma if
set.
Note that additional cpp41 patches are needed to avoid error -115
messages, but that can be applied separately.
Fixes: fdea2d09b997 ("dmaengine: cppi41: Add basic PM runtime support")
Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
---
drivers/usb/musb/musb_cppi41.c | 1 +
drivers/usb/musb/musb_dma.h | 3 +++
drivers/usb/musb/musb_host.c | 16 +++++++++++++++-
3 files changed, 19 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/musb/musb_cppi41.c b/drivers/usb/musb/musb_cppi41.c
--- a/drivers/usb/musb/musb_cppi41.c
+++ b/drivers/usb/musb/musb_cppi41.c
@@ -695,6 +695,7 @@ cppi41_dma_controller_create(struct musb *musb, void __iomem *base)
controller->controller.channel_program = cppi41_dma_channel_program;
controller->controller.channel_abort = cppi41_dma_channel_abort;
controller->controller.is_compatible = cppi41_is_compatible;
+ controller->controller.quirks = MUSB_DMA_QUIRK_CPPI41_IN;
ret = cppi41_dma_controller_start(controller);
if (ret)
diff --git a/drivers/usb/musb/musb_dma.h b/drivers/usb/musb/musb_dma.h
--- a/drivers/usb/musb/musb_dma.h
+++ b/drivers/usb/musb/musb_dma.h
@@ -171,6 +171,8 @@ dma_channel_status(struct dma_channel *c)
return (is_dma_capable() && c) ? c->status : MUSB_DMA_STATUS_UNKNOWN;
}
+#define MUSB_DMA_QUIRK_CPPI41_IN BIT(0)
+
/**
* struct dma_controller - A DMA Controller.
* @start: call this to start a DMA controller;
@@ -196,6 +198,7 @@ struct dma_controller {
int (*is_compatible)(struct dma_channel *channel,
u16 maxpacket,
void *buf, u32 length);
+ unsigned int quirks;
};
/* called after channel_program(), may indicate a fault */
diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
--- a/drivers/usb/musb/musb_host.c
+++ b/drivers/usb/musb/musb_host.c
@@ -743,6 +743,8 @@ static void musb_ep_program(struct musb *musb, u8 epnum,
musb_ep_select(mbase, epnum);
+ dma_controller = musb->dma_controller;
+
if (is_out && !len) {
use_dma = 0;
csr = musb_readw(epio, MUSB_TXCSR);
@@ -751,8 +753,20 @@ static void musb_ep_program(struct musb *musb, u8 epnum,
hw_ep->tx_channel = NULL;
}
+ /*
+ * At least cppi41 in dma will just hang with size of 1 until the
+ * device is disconnected.
+ */
+ if (!is_out && dma_controller &&
+ (dma_controller->quirks & MUSB_DMA_QUIRK_CPPI41_IN)) {
+ use_dma = 0;
+ csr = musb_readw(epio, MUSB_RXCSR);
+ csr &= ~MUSB_RXCSR_DMAENAB;
+ musb_writew(epio, MUSB_RXCSR, csr);
+ hw_ep->rx_channel = NULL;
+ }
+
/* candidate for DMA? */
- dma_controller = musb->dma_controller;
if (use_dma && is_dma_capable() && epnum && dma_controller) {
dma_channel = is_out ? hw_ep->tx_channel : hw_ep->rx_channel;
if (!dma_channel) {
--
2.11.0
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