From 8e5481d98bbf1de0ff06a3e488b668572d578e61 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Fri, 23 Sep 2016 21:38:51 +0200 Subject: serial: stm32: use mapbase instead of membase for DMA Building this driver with a 64-bit dma_addr_t type results in a compiler warning: drivers/tty/serial/stm32-usart.c: In function 'stm32_of_dma_rx_probe': drivers/tty/serial/stm32-usart.c:746:20: error: cast from pointer to integer of different size [-Werror=pointer-to-int-cast] drivers/tty/serial/stm32-usart.c: In function 'stm32_of_dma_tx_probe': drivers/tty/serial/stm32-usart.c:818:20: error: cast from pointer to integer of different size [-Werror=pointer-to-int-cast] While the type conversion here is harmless, this hints at a different problem: we pass an __iomem pointer into a DMA engine, which expects a phys_addr_t. This happens to work because stm32 has no MMU and ioremap() is an identity mapping here, but it's still an incorrect API use. Using dma_addr_t is doubly wrong here, because that would be the result of dma_map_single() rather than the physical address. Using the mapbase instead fixes multiple issues: - the warning is gone - we don't go through ioremap in error - the cast is gone, making it use the correct resource_size_t/phys_addr_t type in the process. Fixes: 3489187204eb ("serial: stm32: adding dma support") Signed-off-by: Arnd Bergmann Reviewed-by: Gerald Baeza Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/stm32-usart.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/tty') diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index 4d3001b77e7e..2adb678a863b 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -743,7 +743,7 @@ static int stm32_of_dma_rx_probe(struct stm32_port *stm32port, /* Configure DMA channel */ memset(&config, 0, sizeof(config)); - config.src_addr = (dma_addr_t)port->membase + ofs->rdr; + config.src_addr = port->mapbase + ofs->rdr; config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; ret = dmaengine_slave_config(stm32port->rx_ch, &config); @@ -815,7 +815,7 @@ static int stm32_of_dma_tx_probe(struct stm32_port *stm32port, /* Configure DMA channel */ memset(&config, 0, sizeof(config)); - config.dst_addr = (dma_addr_t)port->membase + ofs->tdr; + config.dst_addr = port->mapbase + ofs->tdr; config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; ret = dmaengine_slave_config(stm32port->tx_ch, &config); -- cgit v1.2.3-59-g8ed1b