serial: mfd: remove the timeout workaround for A0

This is kind of a revert for commit 669b7a0938e "hsu: add a periodic
timer to check dma rx channel", which is a workaround for a bug in A0
stepping silicon, where a dma rx data timeout is missing for some case.
Since new silicon has fixed it and the old version is phasing out, no
need to carry on it any more.

Signed-off-by: Feng Tang <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/tty/serial/mfd.c

···
 #define mfd_readl(obj, offset)		readl(obj->reg + offset)
 #define mfd_writel(obj, offset, val)	writel(val, obj->reg + offset)
 
-#define HSU_DMA_TIMEOUT_CHECK_FREQ	(HZ/10)
-
 struct hsu_dma_buffer {
 	u8		*buf;
 	dma_addr_t	dma_addr;
···
 	enum dma_data_direction	dirt;
 	struct uart_hsu_port	*uport;
 	void __iomem		*reg;
-	struct timer_list	rx_timer; /* only needed by RX channel */
 };
 
 struct uart_hsu_port {
···
 					 | (0x1 << 24)	/* timeout bit, see HSU Errata 1 */
 					 );
 	chan_writel(rxc, HSU_CH_CR, 0x3);
-
-	mod_timer(&rxc->rx_timer, jiffies + HSU_DMA_TIMEOUT_CHECK_FREQ);
 }
 
 /* Protected by spin_lock_irqsave(port->lock) */
···
 		chan_writel(chan, HSU_CH_CR, 0x3);
 		return;
 	}
-	del_timer(&chan->rx_timer);
 
 	dma_sync_single_for_cpu(port->dev, dbuf->dma_addr,
 			dbuf->dma_size, DMA_FROM_DEVICE);
···
 	tty_flip_buffer_push(tty);
 
 	chan_writel(chan, HSU_CH_CR, 0x3);
-	chan->rx_timer.expires = jiffies + HSU_DMA_TIMEOUT_CHECK_FREQ;
-	add_timer(&chan->rx_timer);
 
 }
 
···
 	struct uart_hsu_port *up =
 		container_of(port, struct uart_hsu_port, port);
 	unsigned long flags;
-
-	del_timer_sync(&up->rxc->rx_timer);
 
 	/* Disable interrupts from this port */
 	up->ier = 0;
···
 	return ret;
 }
 
-static void hsu_dma_rx_timeout(unsigned long data)
-{
-	struct hsu_dma_chan *chan = (void *)data;
-	struct uart_hsu_port *up = chan->uport;
-	struct hsu_dma_buffer *dbuf = &up->rxbuf;
-	int count = 0;
-	unsigned long flags;
-
-	spin_lock_irqsave(&up->port.lock, flags);
-
-	count = chan_readl(chan, HSU_CH_D0SAR) - dbuf->dma_addr;
-
-	if (!count) {
-		mod_timer(&chan->rx_timer, jiffies + HSU_DMA_TIMEOUT_CHECK_FREQ);
-		goto exit;
-	}
-
-	hsu_dma_rx(up, 0);
-exit:
-	spin_unlock_irqrestore(&up->port.lock, flags);
-}
-
 static void hsu_global_init(void)
 {
 	struct hsu_port *hsu;
···
 		dchan->reg = hsu->reg + HSU_DMA_CHANS_REG_OFFSET +
 				i * HSU_DMA_CHANS_REG_LENGTH;
 
-		/* Work around for RX */
-		if (dchan->dirt == DMA_FROM_DEVICE) {
-			init_timer(&dchan->rx_timer);
-			dchan->rx_timer.function = hsu_dma_rx_timeout;
-			dchan->rx_timer.data = (unsigned long)dchan;
-		}
 		dchan++;
 	}