Hi Jeffrey,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v5.14-rc7 next-20210826]
[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]

url:    https://github.com/0day-ci/linux/commits/Jeffrey-Hugo/bus-mhi-core-Use-cached-values-for-calculating-the-shared-write-pointer/20210827-010402
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 73f3af7b4611d77bdaea303fb639333eb28e37d7
config: riscv-randconfig-r042-20210826 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project ea08c4cd1c0869ec5024a8bb3f5cdf06ab03ae83)
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
        # install riscv cross compiling tool for clang build
        # apt-get install binutils-riscv64-linux-gnu
        # https://github.com/0day-ci/linux/commit/82f8b573ef9eb6f068ed842f7ce1009c6bd5b63e
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Jeffrey-Hugo/bus-mhi-core-Use-cached-values-for-calculating-the-shared-write-pointer/20210827-010402
        git checkout 82f8b573ef9eb6f068ed842f7ce1009c6bd5b63e
        # save the attached .config to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross O=build_dir ARCH=riscv SHELL=/bin/bash drivers/bus/mhi/core/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All error/warnings (new ones prefixed by >>):

>> drivers/bus/mhi/core/main.c:542:50: error: use of undeclared identifier 'ring_base'; did you mean 'pfn_base'?
           *ring->ctxt_wp = ring->iommu_base + (ring->wp - ring_base);
                                                           ^~~~~~~~~
                                                           pfn_base
   arch/riscv/include/asm/page.h:82:22: note: 'pfn_base' declared here
   extern unsigned long pfn_base;
                        ^
>> drivers/bus/mhi/core/main.c:542:17: warning: incompatible pointer to integer conversion assigning to 'u64' (aka 'unsigned long long') from 'void *' [-Wint-conversion]
           *ring->ctxt_wp = ring->iommu_base + (ring->wp - ring_base);
                          ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   1 warning and 1 error generated.


vim +542 drivers/bus/mhi/core/main.c

   532	
   533	static void mhi_recycle_ev_ring_element(struct mhi_controller *mhi_cntrl,
   534						struct mhi_ring *ring)
   535	{
   536		/* Update the WP */
   537		ring->wp += ring->el_size;
   538	
   539		if (ring->wp >= (ring->base + ring->len))
   540			ring->wp = ring->base;
   541	
 > 542		*ring->ctxt_wp = ring->iommu_base + (ring->wp - ring_base);
   543	
   544		/* Update the RP */
   545		ring->rp += ring->el_size;
   546		if (ring->rp >= (ring->base + ring->len))
   547			ring->rp = ring->base;
   548	
   549		/* Update to all cores */
   550		smp_wmb();
   551	}
   552	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org