Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755487AbZCFGqu (ORCPT ); Fri, 6 Mar 2009 01:46:50 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754684AbZCFGlL (ORCPT ); Fri, 6 Mar 2009 01:41:11 -0500 Received: from nwd2mail10.analog.com ([137.71.25.55]:39798 "EHLO nwd2mail10.analog.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751345AbZCFGkz (ORCPT ); Fri, 6 Mar 2009 01:40:55 -0500 X-IronPort-AV: E=Sophos;i="4.38,312,1233550800"; d="scan'208";a="83883648" From: Bryan Wu To: alan@lxorguk.ukuu.org.uk Cc: linux-kernel@vger.kernel.org, Sonic Zhang , Bryan Wu Subject: [PATCH 05/18] Blackfin Serial Driver: fix bug - serial port transfer big file from host to target would have more lines Date: Fri, 6 Mar 2009 14:42:47 +0800 Message-Id: <1236321780-28718-6-git-send-email-cooloney@kernel.org> X-Mailer: git-send-email 1.5.6.3 In-Reply-To: <1236321780-28718-1-git-send-email-cooloney@kernel.org> References: <1236321780-28718-1-git-send-email-cooloney@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2933 Lines: 78 From: Sonic Zhang Ignore receiving data if new position is in the same line of current buffer tail and small. Signed-off-by: Sonic Zhang Signed-off-by: Bryan Wu --- drivers/serial/bfin_5xx.c | 31 +++++++++++++++++++++++++++++-- 1 files changed, 29 insertions(+), 2 deletions(-) diff --git a/drivers/serial/bfin_5xx.c b/drivers/serial/bfin_5xx.c index 8d34ccd..5a163f6 100644 --- a/drivers/serial/bfin_5xx.c +++ b/drivers/serial/bfin_5xx.c @@ -407,6 +407,15 @@ void bfin_serial_rx_dma_timeout(struct bfin_serial_port *uart) spin_lock_irqsave(&uart->port.lock, flags); + /* 2D DMA RX buffer ring is used. Because curr_y_count and + * curr_x_count can't be read as an atomic operation, + * curr_y_count should be read before curr_x_count. When + * curr_x_count is read, curr_y_count may already indicate + * next buffer line. But, the position calculated here is + * still indicate the old line. The wrong position data may + * be smaller than current buffer tail, which cause garbages + * are received if it is not prohibit. + */ uart->rx_dma_nrows = get_dma_curr_ycount(uart->rx_dma_channel); x_pos = get_dma_curr_xcount(uart->rx_dma_channel); uart->rx_dma_nrows = DMA_RX_YCOUNT - uart->rx_dma_nrows; @@ -417,7 +426,11 @@ void bfin_serial_rx_dma_timeout(struct bfin_serial_port *uart) x_pos = 0; pos = uart->rx_dma_nrows * DMA_RX_XCOUNT + x_pos; - if (pos != uart->rx_dma_buf.tail) { + /* Ignore receiving data if new position is in the same line of + * current buffer tail and small. + */ + if (pos > uart->rx_dma_buf.tail || + uart->rx_dma_nrows < (uart->rx_dma_buf.tail/DMA_RX_XCOUNT)) { uart->rx_dma_buf.head = pos; bfin_serial_dma_rx_chars(uart); uart->rx_dma_buf.tail = uart->rx_dma_buf.head; @@ -455,11 +468,25 @@ static irqreturn_t bfin_serial_dma_rx_int(int irq, void *dev_id) { struct bfin_serial_port *uart = dev_id; unsigned short irqstat; + int pos; spin_lock(&uart->port.lock); irqstat = get_dma_curr_irqstat(uart->rx_dma_channel); clear_dma_irqstat(uart->rx_dma_channel); - bfin_serial_dma_rx_chars(uart); + + uart->rx_dma_nrows = get_dma_curr_ycount(uart->rx_dma_channel); + uart->rx_dma_nrows = DMA_RX_YCOUNT - uart->rx_dma_nrows; + if (uart->rx_dma_nrows == DMA_RX_YCOUNT) + uart->rx_dma_nrows = 0; + + pos = uart->rx_dma_nrows * DMA_RX_XCOUNT; + if (pos > uart->rx_dma_buf.tail || + uart->rx_dma_nrows < (uart->rx_dma_buf.tail/DMA_RX_XCOUNT)) { + uart->rx_dma_buf.head = pos; + bfin_serial_dma_rx_chars(uart); + uart->rx_dma_buf.tail = uart->rx_dma_buf.head; + } + spin_unlock(&uart->port.lock); return IRQ_HANDLED; -- 1.5.6.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/