Thread (4 messages) 4 messages, 3 authors, 2021-01-11

Re: [PATCH 1/1] usb: gadget: aspeed: fix stop dma register setting.

From: Joel Stanley <joel@jms.id.au>
Date: 2021-01-11 02:25:38
Also in: linux-aspeed, linux-usb, lkml

On Fri, 8 Jan 2021 at 08:13, Ryan Chen [off-list ref] wrote:
quoted hunk ↗ jump to hunk
The vhub engine has two dma mode, one is descriptor list, another
is single stage DMA. Each mode has different stop register setting.
Descriptor list operation (bit2) : 0 disable reset, 1: enable reset
Single mode operation (bit0) : 0 : disable, 1: enable

Signed-off-by: Ryan Chen <ryan_chen@aspeedtech.com>
---
 drivers/usb/gadget/udc/aspeed-vhub/epn.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/gadget/udc/aspeed-vhub/epn.c b/drivers/usb/gadget/udc/aspeed-vhub/epn.c
index 0bd6b20435b8..02d8bfae58fb 100644
--- a/drivers/usb/gadget/udc/aspeed-vhub/epn.c
+++ b/drivers/usb/gadget/udc/aspeed-vhub/epn.c
@@ -420,7 +420,10 @@ static void ast_vhub_stop_active_req(struct ast_vhub_ep *ep,
        u32 state, reg, loops;

        /* Stop DMA activity */
-       writel(0, ep->epn.regs + AST_VHUB_EP_DMA_CTLSTAT);
+       if (ep->epn.desc_mode)
+               writel(VHUB_EP_DMA_CTRL_RESET, ep->epn.regs + AST_VHUB_EP_DMA_CTLSTAT);
+       else
+               writel(0, ep->epn.regs + AST_VHUB_EP_DMA_CTLSTAT);
This looks correct, as whenever the driver re-enables DMA it uses
ep->epn.dma_conf for the value of this register. So we're not losing
any configuration by setting it to 0.

Acked-by: Joel Stanley <joel@jms.id.au>
Fixes: 7ecca2a4080c ("usb/gadget: Add driver for Aspeed SoC virtual hub")

I've cc'd Ben for his ack too.

Cheers,

Joel
        /* Wait for it to complete */
        for (loops = 0; loops < 1000; loops++) {
--
2.17.1
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