Hi Pierre-Yves, I love your patch! Perhaps something to improve: [auto build test WARNING on robh/for-next] [also build test WARNING on v4.19-rc5 next-20180928] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] url: https://github.com/0day-ci/linux/commits/Pierre-Yves-MORDRET/Add-DMA-MDMA-chaining-support/20180928-164058 base: https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next config: i386-allyesconfig (attached as .config) compiler: gcc-7 (Debian 7.3.0-1) 7.3.0 reproduce: # save the attached .config to linux build tree make ARCH=i386 Note: it may well be a FALSE warning. FWIW you are at least aware of it now. http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings All warnings (new ones prefixed by >>): drivers//dma/stm32-dma.c: In function 'stm32_dma_probe': >> drivers//dma/stm32-dma.c:1911:3: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized] dev_info(&pdev->dev, "no dma pool: can't use MDMA: %d\n", ret); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ vim +/ret +1911 drivers//dma/stm32-dma.c 1864 1865 static int stm32_dma_probe(struct platform_device *pdev) 1866 { 1867 struct stm32_dma_chan *chan; 1868 struct stm32_dma_mdma *mchan; 1869 struct stm32_dma_device *dmadev; 1870 struct dma_device *dd; 1871 const struct of_device_id *match; 1872 struct resource *res; 1873 char name[4]; 1874 int i, ret; 1875 1876 match = of_match_device(stm32_dma_of_match, &pdev->dev); 1877 if (!match) { 1878 dev_err(&pdev->dev, "Error: No device match found\n"); 1879 return -ENODEV; 1880 } 1881 1882 dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev), GFP_KERNEL); 1883 if (!dmadev) 1884 return -ENOMEM; 1885 1886 dd = &dmadev->ddev; 1887 1888 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 1889 dmadev->base = devm_ioremap_resource(&pdev->dev, res); 1890 if (IS_ERR(dmadev->base)) 1891 return PTR_ERR(dmadev->base); 1892 1893 dmadev->clk = devm_clk_get(&pdev->dev, NULL); 1894 if (IS_ERR(dmadev->clk)) { 1895 dev_err(&pdev->dev, "Error: Missing controller clock\n"); 1896 return PTR_ERR(dmadev->clk); 1897 } 1898 1899 dmadev->mem2mem = of_property_read_bool(pdev->dev.of_node, 1900 "st,mem2mem"); 1901 1902 dmadev->rst = devm_reset_control_get(&pdev->dev, NULL); 1903 if (!IS_ERR(dmadev->rst)) { 1904 reset_control_assert(dmadev->rst); 1905 udelay(2); 1906 reset_control_deassert(dmadev->rst); 1907 } 1908 1909 dmadev->sram_pool = of_gen_pool_get(pdev->dev.of_node, "sram", 0); 1910 if (!dmadev->sram_pool) > 1911 dev_info(&pdev->dev, "no dma pool: can't use MDMA: %d\n", ret); 1912 else 1913 dev_dbg(&pdev->dev, "SRAM pool: %zu KiB\n", 1914 gen_pool_size(dmadev->sram_pool) / 1024); 1915 1916 dma_cap_set(DMA_SLAVE, dd->cap_mask); 1917 dma_cap_set(DMA_PRIVATE, dd->cap_mask); 1918 dma_cap_set(DMA_CYCLIC, dd->cap_mask); 1919 dd->device_alloc_chan_resources = stm32_dma_alloc_chan_resources; 1920 dd->device_free_chan_resources = stm32_dma_free_chan_resources; 1921 dd->device_tx_status = stm32_dma_tx_status; 1922 dd->device_issue_pending = stm32_dma_issue_pending; 1923 dd->device_prep_slave_sg = stm32_dma_prep_slave_sg; 1924 dd->device_prep_dma_cyclic = stm32_dma_prep_dma_cyclic; 1925 dd->device_config = stm32_dma_slave_config; 1926 dd->device_terminate_all = stm32_dma_terminate_all; 1927 dd->device_synchronize = stm32_dma_synchronize; 1928 dd->src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | 1929 BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | 1930 BIT(DMA_SLAVE_BUSWIDTH_4_BYTES); 1931 dd->dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | 1932 BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | 1933 BIT(DMA_SLAVE_BUSWIDTH_4_BYTES); 1934 dd->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV); 1935 dd->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST; 1936 dd->max_burst = STM32_DMA_MAX_BURST; 1937 dd->dev = &pdev->dev; 1938 INIT_LIST_HEAD(&dd->channels); 1939 1940 if (dmadev->mem2mem) { 1941 dma_cap_set(DMA_MEMCPY, dd->cap_mask); 1942 dd->device_prep_dma_memcpy = stm32_dma_prep_dma_memcpy; 1943 dd->directions |= BIT(DMA_MEM_TO_MEM); 1944 } 1945 1946 for (i = 0; i < STM32_DMA_MAX_CHANNELS; i++) { 1947 chan = &dmadev->chan[i]; 1948 chan->id = i; 1949 chan->vchan.desc_free = stm32_dma_desc_free; 1950 vchan_init(&chan->vchan, dd); 1951 1952 mchan = &chan->mchan; 1953 if (dmadev->sram_pool) { 1954 snprintf(name, sizeof(name), "ch%d", chan->id); 1955 mchan->chan = dma_request_slave_channel(dd->dev, name); 1956 if (!mchan->chan) 1957 dev_info(&pdev->dev, 1958 "can't request MDMA chan for %s\n", 1959 name); 1960 } 1961 } 1962 1963 ret = dma_async_device_register(dd); 1964 if (ret) 1965 return ret; 1966 1967 for (i = 0; i < STM32_DMA_MAX_CHANNELS; i++) { 1968 chan = &dmadev->chan[i]; 1969 res = platform_get_resource(pdev, IORESOURCE_IRQ, i); 1970 if (!res) { 1971 ret = -EINVAL; 1972 dev_err(&pdev->dev, "No irq resource for chan %d\n", i); 1973 goto err_unregister; 1974 } 1975 chan->irq = res->start; 1976 ret = devm_request_irq(&pdev->dev, chan->irq, 1977 stm32_dma_chan_irq, 0, 1978 dev_name(chan2dev(chan)), chan); 1979 if (ret) { 1980 dev_err(&pdev->dev, 1981 "request_irq failed with err %d channel %d\n", 1982 ret, i); 1983 goto err_unregister; 1984 } 1985 } 1986 1987 ret = of_dma_controller_register(pdev->dev.of_node, 1988 stm32_dma_of_xlate, dmadev); 1989 if (ret < 0) { 1990 dev_err(&pdev->dev, 1991 "STM32 DMA DMA OF registration failed %d\n", ret); 1992 goto err_unregister; 1993 } 1994 1995 platform_set_drvdata(pdev, dmadev); 1996 1997 dev_info(&pdev->dev, "STM32 DMA driver registered\n"); 1998 1999 return 0; 2000 2001 err_unregister: 2002 dma_async_device_unregister(dd); 2003 2004 return ret; 2005 } 2006 --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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