From 962845da54afe2fc7ebf64c2d8bb5aa65a826b2f Mon Sep 17 00:00:00 2001 From: Dong Aisheng Date: Fri, 7 Nov 2014 16:45:14 +0800 Subject: [PATCH] can: m_can: add missing message RAM initialization The M_CAN message RAM is usually equipped with a parity or ECC functionality. But RAM cells suffer a hardware reset and can therefore hold arbitrary content at startup - including parity and/or ECC bits. To prevent the M_CAN controller detecting checksum errors when reading potentially uninitialized TX message RAM content to transmit CAN frames the TX message RAM has to be written with (any kind of) initial data. Signed-off-by: Dong Aisheng Signed-off-by: Marc Kleine-Budde --- drivers/net/can/m_can/m_can.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c index e61886bf1bb3..268ad5064c47 100644 --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -1010,7 +1010,7 @@ static int m_can_of_parse_mram(struct platform_device *pdev, struct resource *res; void __iomem *addr; u32 out_val[MRAM_CFG_LEN]; - int ret; + int i, start, end, ret; /* message ram could be shared */ res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "message_ram"); @@ -1061,6 +1061,15 @@ static int m_can_of_parse_mram(struct platform_device *pdev, priv->mcfg[MRAM_TXE].off, priv->mcfg[MRAM_TXE].num, priv->mcfg[MRAM_TXB].off, priv->mcfg[MRAM_TXB].num); + /* initialize the entire Message RAM in use to avoid possible + * ECC/parity checksum errors when reading an uninitialized buffer + */ + start = priv->mcfg[MRAM_SIDF].off; + end = priv->mcfg[MRAM_TXB].off + + priv->mcfg[MRAM_TXB].num * TXB_ELEMENT_SIZE; + for (i = start; i < end; i += 4) + writel(0x0, priv->mram_base + i); + return 0; } -- 2.30.2