diff options
Diffstat (limited to 'drivers/misc/cxl/native.c')
| -rw-r--r-- | drivers/misc/cxl/native.c | 58 |
1 files changed, 51 insertions, 7 deletions
diff --git a/drivers/misc/cxl/native.c b/drivers/misc/cxl/native.c index 120c468ee9e0..e77450567f69 100644 --- a/drivers/misc/cxl/native.c +++ b/drivers/misc/cxl/native.c @@ -21,10 +21,10 @@ #include "cxl.h" #include "trace.h" -static int afu_control(struct cxl_afu *afu, u64 command, +static int afu_control(struct cxl_afu *afu, u64 command, u64 clear, u64 result, u64 mask, bool enabled) { - u64 AFU_Cntl = cxl_p2n_read(afu, CXL_AFU_Cntl_An); + u64 AFU_Cntl; unsigned long timeout = jiffies + (HZ * CXL_TIMEOUT); int rc = 0; @@ -33,7 +33,8 @@ static int afu_control(struct cxl_afu *afu, u64 command, trace_cxl_afu_ctrl(afu, command); - cxl_p2n_write(afu, CXL_AFU_Cntl_An, AFU_Cntl | command); + AFU_Cntl = cxl_p2n_read(afu, CXL_AFU_Cntl_An); + cxl_p2n_write(afu, CXL_AFU_Cntl_An, (AFU_Cntl & ~clear) | command); AFU_Cntl = cxl_p2n_read(afu, CXL_AFU_Cntl_An); while ((AFU_Cntl & mask) != result) { @@ -67,7 +68,7 @@ static int afu_enable(struct cxl_afu *afu) { pr_devel("AFU enable request\n"); - return afu_control(afu, CXL_AFU_Cntl_An_E, + return afu_control(afu, CXL_AFU_Cntl_An_E, 0, CXL_AFU_Cntl_An_ES_Enabled, CXL_AFU_Cntl_An_ES_MASK, true); } @@ -76,7 +77,8 @@ int cxl_afu_disable(struct cxl_afu *afu) { pr_devel("AFU disable request\n"); - return afu_control(afu, 0, CXL_AFU_Cntl_An_ES_Disabled, + return afu_control(afu, 0, CXL_AFU_Cntl_An_E, + CXL_AFU_Cntl_An_ES_Disabled, CXL_AFU_Cntl_An_ES_MASK, false); } @@ -85,7 +87,7 @@ static int native_afu_reset(struct cxl_afu *afu) { pr_devel("AFU reset request\n"); - return afu_control(afu, CXL_AFU_Cntl_An_RA, + return afu_control(afu, CXL_AFU_Cntl_An_RA, 0, CXL_AFU_Cntl_An_RS_Complete | CXL_AFU_Cntl_An_ES_Disabled, CXL_AFU_Cntl_An_RS_MASK | CXL_AFU_Cntl_An_ES_MASK, false); @@ -595,7 +597,33 @@ static int deactivate_afu_directed(struct cxl_afu *afu) cxl_sysfs_afu_m_remove(afu); cxl_chardev_afu_remove(afu); - cxl_ops->afu_reset(afu); + /* + * The CAIA section 2.2.1 indicates that the procedure for starting and + * stopping an AFU in AFU directed mode is AFU specific, which is not + * ideal since this code is generic and with one exception has no + * knowledge of the AFU. This is in contrast to the procedure for + * disabling a dedicated process AFU, which is documented to just + * require a reset. The architecture does indicate that both an AFU + * reset and an AFU disable should result in the AFU being disabled and + * we do both followed by a PSL purge for safety. + * + * Notably we used to have some issues with the disable sequence on PSL + * cards, which is why we ended up using this heavy weight procedure in + * the first place, however a bug was discovered that had rendered the + * disable operation ineffective, so it is conceivable that was the + * sole explanation for those difficulties. Careful regression testing + * is recommended if anyone attempts to remove or reorder these + * operations. + * + * The XSL on the Mellanox CX4 behaves a little differently from the + * PSL based cards and will time out an AFU reset if the AFU is still + * enabled. That card is special in that we do have a means to identify + * it from this code, so in that case we skip the reset and just use a + * disable/purge to avoid the timeout and corresponding noise in the + * kernel log. + */ + if (afu->adapter->native->sl_ops->needs_reset_before_disable) + cxl_ops->afu_reset(afu); cxl_afu_disable(afu); cxl_psl_purge(afu); @@ -735,6 +763,22 @@ static int native_attach_process(struct cxl_context *ctx, bool kernel, static inline int detach_process_native_dedicated(struct cxl_context *ctx) { + /* + * The CAIA section 2.1.1 indicates that we need to do an AFU reset to + * stop the AFU in dedicated mode (we therefore do not make that + * optional like we do in the afu directed path). It does not indicate + * that we need to do an explicit disable (which should occur + * implicitly as part of the reset) or purge, but we do these as well + * to be on the safe side. + * + * Notably we used to have some issues with the disable sequence + * (before the sequence was spelled out in the architecture) which is + * why we were so heavy weight in the first place, however a bug was + * discovered that had rendered the disable operation ineffective, so + * it is conceivable that was the sole explanation for those + * difficulties. Point is, we should be careful and do some regression + * testing if we ever attempt to remove any part of this procedure. + */ cxl_ops->afu_reset(ctx->afu); cxl_afu_disable(ctx->afu); cxl_psl_purge(ctx->afu); |