From: Ian Munsie Date: Wed, 29 Jun 2016 18:51:26 +0000 (+1000) Subject: cxl: Workaround XSL bug that does not clear the RA bit after a reset X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=2a4f667aadb2d61c289a52a0d6dbc7e4e3aa009f;p=linux-beck.git cxl: Workaround XSL bug that does not clear the RA bit after a reset An issue was noted in our debug logs where the XSL would leave the RA bit asserted after an AFU reset operation, which would effectively prevent further AFU reset operations from working. Workaround the issue by clearing the RA bit with an MMIO write if it is still asserted after any AFU control operation. Signed-off-by: Ian Munsie Reviewed-by: Frederic Barrat Signed-off-by: Michael Ellerman --- diff --git a/drivers/misc/cxl/native.c b/drivers/misc/cxl/native.c index e77450567f69..04c27e41b654 100644 --- a/drivers/misc/cxl/native.c +++ b/drivers/misc/cxl/native.c @@ -55,6 +55,16 @@ static int afu_control(struct cxl_afu *afu, u64 command, u64 clear, cpu_relax(); AFU_Cntl = cxl_p2n_read(afu, CXL_AFU_Cntl_An); }; + + if (AFU_Cntl & CXL_AFU_Cntl_An_RA) { + /* + * Workaround for a bug in the XSL used in the Mellanox CX4 + * that fails to clear the RA bit after an AFU reset, + * preventing subsequent AFU resets from working. + */ + cxl_p2n_write(afu, CXL_AFU_Cntl_An, AFU_Cntl & ~CXL_AFU_Cntl_An_RA); + } + pr_devel("AFU command complete: %llx\n", command); afu->enabled = enabled; out: