[PATCH 2/4] soc: aspeed: Add UART DMA support

[kernel test robot]

Hi Chia-Wei,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on tty/tty-testing]
[also build test WARNING on tty/tty-next tty/tty-linus robh/for-next driver-core/driver-core-testing driver-core/driver-core-next driver-core/driver-core-linus usb/usb-testing usb/usb-next usb/usb-linus linus/master v6.2-rc7 next-20230210]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Chia-Wei-Wang/dt-bindings-aspeed-Add-UART-controller/20230210-152832
base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git tty-testing
patch link:    https://lore.kernel.org/r/20230210072643.2772-3-chiawei_wang%40aspeedtech.com
patch subject: [PATCH 2/4] soc: aspeed: Add UART DMA support
config: sh-allmodconfig (https://download.01.org/0day-ci/archive/20230210/202302101749.ctd9pkv1-lkp@intel.com/config)
compiler: sh4-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/b1e3a89584657d9b0398f3f46b09dc4229835fa3
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Chia-Wei-Wang/dt-bindings-aspeed-Add-UART-controller/20230210-152832
        git checkout b1e3a89584657d9b0398f3f46b09dc4229835fa3
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=sh olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=sh SHELL=/bin/bash drivers/soc/aspeed/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp at intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202302101749.ctd9pkv1-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/soc/aspeed/aspeed-udma.c: In function 'aspeed_udma_request_chan':
>> drivers/soc/aspeed/aspeed-udma.c:194:13: warning: variable 'retval' set but not used [-Wunused-but-set-variable]
     194 |         int retval = 0;
         |             ^~~~~~


vim +/retval +194 drivers/soc/aspeed/aspeed-udma.c

   189	
   190	static int aspeed_udma_request_chan(u32 ch_no, dma_addr_t addr,
   191			struct circ_buf *rb, u32 rb_sz,
   192			aspeed_udma_cb_t cb, void *id, bool dis_tmout, bool is_tx)
   193	{
 > 194		int retval = 0;
   195		int rbsz_code;
   196	
   197		u32 reg;
   198		unsigned long flags;
   199		struct aspeed_udma_chan *ch;
   200	
   201		if (ch_no > UDMA_MAX_CHANNEL) {
   202			retval = -EINVAL;
   203			goto out;
   204		}
   205	
   206		if (IS_ERR_OR_NULL(rb) || IS_ERR_OR_NULL(rb->buf)) {
   207			retval = -EINVAL;
   208			goto out;
   209		}
   210	
   211		rbsz_code = aspeed_udma_get_bufsz_code(rb_sz);
   212		if (rbsz_code < 0) {
   213			retval = -EINVAL;
   214			goto out;
   215		}
   216	
   217		spin_lock_irqsave(&udma->lock, flags);
   218	
   219		if (is_tx) {
   220			reg = readl(udma->regs + UDMA_TX_DMA_INT_EN);
   221			if (reg & (0x1 << ch_no)) {
   222				retval = -EBUSY;
   223				goto unlock_n_out;
   224			}
   225	
   226			reg |= (0x1 << ch_no);
   227			writel(reg, udma->regs + UDMA_TX_DMA_INT_EN);
   228	
   229			reg = readl(udma->regs + UDMA_CHX_TX_CTRL(ch_no));
   230			reg |= (dis_tmout) ? UDMA_TX_CTRL_TMOUT_DISABLE : 0;
   231			reg |= (rbsz_code << UDMA_TX_CTRL_BUFSZ_SHIFT) & UDMA_TX_CTRL_BUFSZ_MASK;
   232			writel(reg, udma->regs + UDMA_CHX_TX_CTRL(ch_no));
   233	
   234			writel(addr, udma->regs + UDMA_CHX_TX_BUF_BASE(ch_no));
   235		} else {
   236			reg = readl(udma->regs + UDMA_RX_DMA_INT_EN);
   237			if (reg & (0x1 << ch_no)) {
   238				retval = -EBUSY;
   239				goto unlock_n_out;
   240			}
   241	
   242			reg |= (0x1 << ch_no);
   243			writel(reg, udma->regs + UDMA_RX_DMA_INT_EN);
   244	
   245			reg = readl(udma->regs + UDMA_CHX_RX_CTRL(ch_no));
   246			reg |= (dis_tmout) ? UDMA_RX_CTRL_TMOUT_DISABLE : 0;
   247			reg |= (rbsz_code << UDMA_RX_CTRL_BUFSZ_SHIFT) & UDMA_RX_CTRL_BUFSZ_MASK;
   248			writel(reg, udma->regs + UDMA_CHX_RX_CTRL(ch_no));
   249	
   250			writel(addr, udma->regs + UDMA_CHX_RX_BUF_BASE(ch_no));
   251		}
   252	
   253		ch = (is_tx) ? &udma->tx_chs[ch_no] : &udma->rx_chs[ch_no];
   254		ch->rb = rb;
   255		ch->rb_sz = rb_sz;
   256		ch->cb = cb;
   257		ch->cb_arg = id;
   258		ch->dma_addr = addr;
   259		ch->dis_tmout = dis_tmout;
   260	
   261	unlock_n_out:
   262		spin_unlock_irqrestore(&udma->lock, flags);
   263	out:
   264		return 0;
   265	}
   266	

-- 
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https://github.com/intel/lkp-tests