[PATCH v13 07/15] cxl: Share HDM decoder register unpacking
From: Srirangan Madhavan
Date: Tue Sep 22 2026 - 04:47:58 EST
Factor HDM register parsing into cxl_hdm_unpack_decoder(). Validate local
values before publishing complete settings, including committed, locked,
and target-or-skip state.
Pass endpoint skip state to the DPA reservation helper instead of
updating live endpoint state, preserving its ownership.
Signed-off-by: Srirangan Madhavan <smadhavan@xxxxxxxxxx>
---
drivers/cxl/core/core.h | 4 ++
drivers/cxl/core/hdm.c | 74 +++++++++++++------------------------
drivers/cxl/core/resource.c | 55 +++++++++++++++++++++++++++
3 files changed, 85 insertions(+), 48 deletions(-)
diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
index 3444479cbade..7e2723d1f87d 100644
--- a/drivers/cxl/core/core.h
+++ b/drivers/cxl/core/core.h
@@ -142,6 +142,10 @@ extern struct cxl_rwsem cxl_rwsem;
void cxl_commit_start(void __iomem *hdm, struct cxl_decoder_settings *settings);
int cxl_commit_wait(void __iomem *hdm, struct cxl_decoder_settings *settings);
+int cxl_hdm_unpack_decoder(struct cxl_decoder_settings *settings, int id,
+ u32 ctrl, u64 base, u64 size,
+ u64 target_or_skip_reg_val);
+
int cxl_memdev_init(void);
void cxl_memdev_exit(void);
void cxl_mbox_init(void);
diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
index b3ddc02df65e..98268e8e15b2 100644
--- a/drivers/cxl/core/hdm.c
+++ b/drivers/cxl/core/hdm.c
@@ -932,8 +932,8 @@ static int init_hdm_decoder(struct cxl_port *port, struct cxl_decoder *cxld,
u64 *dpa_base, struct cxl_endpoint_dvsec_info *info)
{
struct cxl_endpoint_decoder *cxled = NULL;
- u64 size, base, skip, dpa_size, lo, hi;
- bool committed;
+ struct cxl_decoder_settings settings;
+ u64 size, base, skip, dpa_size, lo, hi, target_or_skip_reg_val;
u32 remainder;
int i, rc;
u32 ctrl;
@@ -953,35 +953,34 @@ static int init_hdm_decoder(struct cxl_port *port, struct cxl_decoder *cxld,
lo = readl(hdm + CXL_HDM_DECODER0_SIZE_LOW_OFFSET(which));
hi = readl(hdm + CXL_HDM_DECODER0_SIZE_HIGH_OFFSET(which));
size = (hi << 32) + lo;
- committed = !!(ctrl & CXL_HDM_DECODER0_CTRL_COMMITTED);
+ lo = readl(hdm + CXL_HDM_DECODER0_TL_LOW(which));
+ hi = readl(hdm + CXL_HDM_DECODER0_TL_HIGH(which));
+ target_or_skip_reg_val = (hi << 32) + lo;
+ rc = cxl_hdm_unpack_decoder(&settings, which, ctrl, base, size,
+ target_or_skip_reg_val);
+ if (rc) {
+ dev_warn(&port->dev,
+ "decoder%d.%d: Invalid decoder configuration (ctrl: %#x): %d\n",
+ port->id, cxld->id, ctrl, rc);
+ return rc;
+ }
+
cxld->commit = cxl_decoder_commit;
cxld->reset = cxl_decoder_reset;
-
- if (!committed)
- size = 0;
- if (base == U64_MAX || size == U64_MAX) {
- dev_warn(&port->dev, "decoder%d.%d: Invalid resource range\n",
- port->id, cxld->id);
- return -ENXIO;
- }
+ cxld->config = settings.config;
+ size = range_len(&cxld->hpa_range);
if (info)
cxled = to_cxl_endpoint_decoder(&cxld->dev);
- cxld->hpa_range = (struct range) {
- .start = base,
- .end = base + size - 1,
- };
+ if (!cxled && cxld->interleave_ways > 8) {
+ dev_warn(&port->dev,
+ "decoder%d.%d: Invalid target count: %d\n",
+ port->id, cxld->id, cxld->interleave_ways);
+ return -ENXIO;
+ }
/* decoders are enabled if committed */
- if (committed) {
- cxld->flags |= CXL_DECODER_F_ENABLE;
- if (ctrl & CXL_HDM_DECODER0_CTRL_LOCK)
- cxld->flags |= CXL_DECODER_F_LOCK;
- if (FIELD_GET(CXL_HDM_DECODER0_CTRL_HOSTONLY, ctrl))
- cxld->target_type = CXL_DECODER_HOSTONLYMEM;
- else
- cxld->target_type = CXL_DECODER_DEVMEM;
-
+ if (cxld->flags & CXL_DECODER_F_ENABLE) {
guard(rwsem_write)(&cxl_rwsem.region);
if (cxld->id != cxl_num_decoders_committed(port)) {
dev_warn(&port->dev,
@@ -1015,38 +1014,19 @@ static int init_hdm_decoder(struct cxl_port *port, struct cxl_decoder *cxld,
writel(ctrl, hdm + CXL_HDM_DECODER0_CTRL_OFFSET(which));
}
}
- rc = eiw_to_ways(FIELD_GET(CXL_HDM_DECODER0_CTRL_IW_MASK, ctrl),
- &cxld->interleave_ways);
- if (rc) {
- dev_warn(&port->dev,
- "decoder%d.%d: Invalid interleave ways (ctrl: %#x)\n",
- port->id, cxld->id, ctrl);
- return rc;
- }
- rc = eig_to_granularity(FIELD_GET(CXL_HDM_DECODER0_CTRL_IG_MASK, ctrl),
- &cxld->interleave_granularity);
- if (rc) {
- dev_warn(&port->dev,
- "decoder%d.%d: Invalid interleave granularity (ctrl: %#x)\n",
- port->id, cxld->id, ctrl);
- return rc;
- }
-
dev_dbg(&port->dev, "decoder%d.%d: range: %#llx-%#llx iw: %d ig: %d\n",
port->id, cxld->id, cxld->hpa_range.start, cxld->hpa_range.end,
cxld->interleave_ways, cxld->interleave_granularity);
if (!cxled) {
- lo = readl(hdm + CXL_HDM_DECODER0_TL_LOW(which));
- hi = readl(hdm + CXL_HDM_DECODER0_TL_HIGH(which));
- target_list.value = (hi << 32) + lo;
+ target_list.value = settings.target_or_skip_reg_val;
for (i = 0; i < cxld->interleave_ways; i++)
cxld->target_map[i] = target_list.target_id[i];
return 0;
}
- if (!committed)
+ if (!(cxld->flags & CXL_DECODER_F_ENABLE))
return 0;
dpa_size = div_u64_rem(size, cxld->interleave_ways, &remainder);
@@ -1056,9 +1036,7 @@ static int init_hdm_decoder(struct cxl_port *port, struct cxl_decoder *cxld,
port->id, cxld->id, size, cxld->interleave_ways);
return -ENXIO;
}
- lo = readl(hdm + CXL_HDM_DECODER0_SKIP_LOW(which));
- hi = readl(hdm + CXL_HDM_DECODER0_SKIP_HIGH(which));
- skip = (hi << 32) + lo;
+ skip = settings.target_or_skip_reg_val;
rc = devm_cxl_dpa_reserve(cxled, *dpa_base + skip, dpa_size, skip);
if (rc) {
dev_err(&port->dev,
diff --git a/drivers/cxl/core/resource.c b/drivers/cxl/core/resource.c
index 1b4742622054..7eea2bc38d94 100644
--- a/drivers/cxl/core/resource.c
+++ b/drivers/cxl/core/resource.c
@@ -109,3 +109,58 @@ int cxl_commit_wait(void __iomem *hdm, struct cxl_decoder_settings *settings)
return cxld_await_commit(hdm, settings->config.id);
}
EXPORT_SYMBOL_FOR_MODULES(cxl_commit_wait, "cxl_core");
+
+int cxl_hdm_unpack_decoder(struct cxl_decoder_settings *settings, int id,
+ u32 ctrl, u64 base, u64 size,
+ u64 target_or_skip_reg_val)
+{
+ bool committed = FIELD_GET(CXL_HDM_DECODER0_CTRL_COMMITTED, ctrl);
+ enum cxl_decoder_type target_type;
+ int interleave_granularity;
+ int interleave_ways;
+ unsigned long flags = 0;
+ struct range hpa_range;
+ int rc;
+
+ if (!committed)
+ size = 0;
+ if (base == U64_MAX || size == U64_MAX ||
+ (size && base > U64_MAX - (size - 1)))
+ return -ENXIO;
+
+ hpa_range = (struct range) {
+ .start = base,
+ .end = base + size - 1,
+ };
+ target_type = FIELD_GET(CXL_HDM_DECODER0_CTRL_HOSTONLY, ctrl) ?
+ CXL_DECODER_HOSTONLYMEM : CXL_DECODER_DEVMEM;
+ if (committed) {
+ flags |= CXL_DECODER_F_ENABLE;
+ if (ctrl & CXL_HDM_DECODER0_CTRL_LOCK)
+ flags |= CXL_DECODER_F_LOCK;
+ }
+
+ rc = eiw_to_ways(FIELD_GET(CXL_HDM_DECODER0_CTRL_IW_MASK, ctrl),
+ &interleave_ways);
+ if (rc)
+ return rc;
+ rc = eig_to_granularity(FIELD_GET(CXL_HDM_DECODER0_CTRL_IG_MASK, ctrl),
+ &interleave_granularity);
+ if (rc)
+ return rc;
+
+ *settings = (struct cxl_decoder_settings) {
+ .config = {
+ .id = id,
+ .hpa_range = hpa_range,
+ .interleave_ways = interleave_ways,
+ .interleave_granularity = interleave_granularity,
+ .target_type = target_type,
+ .flags = flags,
+ },
+ .target_or_skip_reg_val = target_or_skip_reg_val,
+ };
+
+ return 0;
+}
+EXPORT_SYMBOL_FOR_MODULES(cxl_hdm_unpack_decoder, "cxl_core");
--
2.43.0