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authorIan Munsie <imunsie@au1.ibm.com>2014-12-08 19:17:59 +1100
committerMichael Ellerman <mpe@ellerman.id.au>2014-12-29 15:45:43 +1100
commitd6a6af2c181400aade59417e698c7cd9bec8804e (patch)
tree02269e6dda585d14c1ea7a6c1c5f6c59829b6dbe /drivers/misc/cxl
parent13da704682471669685ccc3fe111fd6c0127b2eb (diff)
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cxl: Disable AFU debug flag
Upon inspection of the implementation specific registers, it was discovered that the high bit of the implementation specific RXCTL register was enabled, which enables the DEADB00F debug feature. The debug feature causes MMIO reads to a disabled AFU to respond with 0xDEADB00F instead of all Fs. In general this should not be visible as the kernel will only allow MMIO access to enabled AFUs, but there may be some circumstances where an AFU may become disabled while it is use. One such case would be an AFU designed to only be used in the dedicated process mode and to disable itself after it has completed it's work (however even in that case the effects of this debug flag would be limited as the userspace application must have completed any required MMIO accesses before the AFU disables itself with or without the flag). This patch removes the debug flag and replaces the magic value programmed into this register with a preprocessor define so it is clearer what the rest of this initialisation does. Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'drivers/misc/cxl')
-rw-r--r--drivers/misc/cxl/cxl.h7
-rw-r--r--drivers/misc/cxl/pci.c2
2 files changed, 8 insertions, 1 deletions
diff --git a/drivers/misc/cxl/cxl.h b/drivers/misc/cxl/cxl.h
index 28078f8894a5..0df04380bfd6 100644
--- a/drivers/misc/cxl/cxl.h
+++ b/drivers/misc/cxl/cxl.h
@@ -287,6 +287,13 @@ static const cxl_p2n_reg_t CXL_PSL_WED_An = {0x0A0};
#define CXL_PE_SOFTWARE_STATE_S (1ul << (31 - 30)) /* Suspend */
#define CXL_PE_SOFTWARE_STATE_T (1ul << (31 - 31)) /* Terminate */
+/****** CXL_PSL_RXCTL_An (Implementation Specific) **************************
+ * Controls AFU Hang Pulse, which sets the timeout for the AFU to respond to
+ * the PSL for any response (except MMIO). Timeouts will occur between 1x to 2x
+ * of the hang pulse frequency.
+ */
+#define CXL_PSL_RXCTL_AFUHP_4S 0x7000000000000000ULL
+
/* SPA->sw_command_status */
#define CXL_SPA_SW_CMD_MASK 0xffff000000000000ULL
#define CXL_SPA_SW_CMD_TERMINATE 0x0001000000000000ULL
diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c
index 0f2cc9f8b4db..2ccd0a91d486 100644
--- a/drivers/misc/cxl/pci.c
+++ b/drivers/misc/cxl/pci.c
@@ -348,7 +348,7 @@ static int init_implementation_afu_regs(struct cxl_afu *afu)
cxl_p1n_write(afu, CXL_PSL_COALLOC_A, 0xFF000000FEFEFEFEULL);
/* for debugging with trace arrays */
cxl_p1n_write(afu, CXL_PSL_SLICE_TRACE, 0x0000FFFF00000000ULL);
- cxl_p1n_write(afu, CXL_PSL_RXCTL_A, 0xF000000000000000ULL);
+ cxl_p1n_write(afu, CXL_PSL_RXCTL_A, CXL_PSL_RXCTL_AFUHP_4S);
return 0;
}