3 files changed, 71 insertions, 23 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-devtrace.h b/drivers/net/wireless/iwlwifi/iwl-devtrace.h
index 9a0f45ec9e01..10f01793d7a6 100644
--- a/drivers/net/wireless/iwlwifi/iwl-devtrace.h
+++ b/drivers/net/wireless/iwlwifi/iwl-devtrace.h
@@ -349,25 +349,23 @@ TRACE_EVENT(iwlwifi_dev_rx_data,
 TRACE_EVENT(iwlwifi_dev_hcmd,
         TP_PROTO(const struct device *dev,
                  struct iwl_host_cmd *cmd, u16 total_size,
-                 const void *hdr, size_t hdr_len),
-        TP_ARGS(dev, cmd, total_size, hdr, hdr_len),
+                 struct iwl_cmd_header *hdr),
+        TP_ARGS(dev, cmd, total_size, hdr),
         TP_STRUCT__entry(
                 DEV_ENTRY
                 __dynamic_array(u8, hcmd, total_size)
                 __field(u32, flags)
         ),
         TP_fast_assign(
-                int i, offset = hdr_len;
+                int i, offset = sizeof(*hdr);
 
                 DEV_ASSIGN;
                 __entry->flags = cmd->flags;
-                memcpy(__get_dynamic_array(hcmd), hdr, hdr_len);
+                memcpy(__get_dynamic_array(hcmd), hdr, sizeof(*hdr));
 
                 for (i = 0; i < IWL_MAX_CMD_TFDS; i++) {
                         if (!cmd->len[i])
                                 continue;
-                        if (!(cmd->dataflags[i] & IWL_HCMD_DFL_NOCOPY))
-                                continue;
                         memcpy((u8 *)__get_dynamic_array(hcmd) + offset,
                                cmd->data[i], cmd->len[i]);
                         offset += cmd->len[i];
diff --git a/drivers/net/wireless/iwlwifi/pcie/internal.h b/drivers/net/wireless/iwlwifi/pcie/internal.h
index aa2a39a637dd..3d62e8055352 100644
--- a/drivers/net/wireless/iwlwifi/pcie/internal.h
+++ b/drivers/net/wireless/iwlwifi/pcie/internal.h
@@ -182,6 +182,15 @@ struct iwl_queue {
 #define TFD_TX_CMD_SLOTS 256
 #define TFD_CMD_SLOTS 32
 
+/*
+ * The FH will write back to the first TB only, so we need
+ * to copy some data into the buffer regardless of whether
+ * it should be mapped or not. This indicates how much to
+ * copy, even for HCMDs it must be big enough to fit the
+ * DRAM scratch from the TX cmd, at least 16 bytes.
+ */
+#define IWL_HCMD_MIN_COPY_SIZE  16
+
 struct iwl_pcie_txq_entry {
         struct iwl_device_cmd *cmd;
         struct iwl_device_cmd *copy_cmd;
diff --git a/drivers/net/wireless/iwlwifi/pcie/tx.c b/drivers/net/wireless/iwlwifi/pcie/tx.c
index 8e9e3212fe78..8b625a7f5685 100644
--- a/drivers/net/wireless/iwlwifi/pcie/tx.c
+++ b/drivers/net/wireless/iwlwifi/pcie/tx.c
@@ -1152,10 +1152,12 @@ static int iwl_pcie_enqueue_hcmd(struct iwl_trans *trans,
         void *dup_buf = NULL;
         dma_addr_t phys_addr;
         int idx;
-        u16 copy_size, cmd_size;
+        u16 copy_size, cmd_size, dma_size;
         bool had_nocopy = false;
         int i;
         u32 cmd_pos;
+        const u8 *cmddata[IWL_MAX_CMD_TFDS];
+        u16 cmdlen[IWL_MAX_CMD_TFDS];
 
         copy_size = sizeof(out_cmd->hdr);
         cmd_size = sizeof(out_cmd->hdr);
@@ -1164,8 +1166,23 @@ static int iwl_pcie_enqueue_hcmd(struct iwl_trans *trans,
         BUILD_BUG_ON(IWL_MAX_CMD_TFDS > IWL_NUM_OF_TBS - 1);
 
         for (i = 0; i < IWL_MAX_CMD_TFDS; i++) {
+                cmddata[i] = cmd->data[i];
+                cmdlen[i] = cmd->len[i];
+
                 if (!cmd->len[i])
                         continue;
+
+                /* need at least IWL_HCMD_MIN_COPY_SIZE copied */
+                if (copy_size < IWL_HCMD_MIN_COPY_SIZE) {
+                        int copy = IWL_HCMD_MIN_COPY_SIZE - copy_size;
+
+                        if (copy > cmdlen[i])
+                                copy = cmdlen[i];
+                        cmdlen[i] -= copy;
+                        cmddata[i] += copy;
+                        copy_size += copy;
+                }
+
                 if (cmd->dataflags[i] & IWL_HCMD_DFL_NOCOPY) {
                         had_nocopy = true;
                         if (WARN_ON(cmd->dataflags[i] & IWL_HCMD_DFL_DUP)) {
@@ -1185,7 +1202,7 @@ static int iwl_pcie_enqueue_hcmd(struct iwl_trans *trans,
                                 goto free_dup_buf;
                         }
 
-                        dup_buf = kmemdup(cmd->data[i], cmd->len[i],
+                        dup_buf = kmemdup(cmddata[i], cmdlen[i],
                                           GFP_ATOMIC);
                         if (!dup_buf)
                                 return -ENOMEM;
@@ -1195,7 +1212,7 @@ static int iwl_pcie_enqueue_hcmd(struct iwl_trans *trans,
                                 idx = -EINVAL;
                                 goto free_dup_buf;
                         }
-                        copy_size += cmd->len[i];
+                        copy_size += cmdlen[i];
                 }
                 cmd_size += cmd->len[i];
         }
@@ -1242,14 +1259,31 @@ static int iwl_pcie_enqueue_hcmd(struct iwl_trans *trans,
 
         /* and copy the data that needs to be copied */
         cmd_pos = offsetof(struct iwl_device_cmd, payload);
+        copy_size = sizeof(out_cmd->hdr);
         for (i = 0; i < IWL_MAX_CMD_TFDS; i++) {
-                if (!cmd->len[i])
+                int copy = 0;
+
+                if (!cmd->len)
                         continue;
-                if (cmd->dataflags[i] & (IWL_HCMD_DFL_NOCOPY |
-                                         IWL_HCMD_DFL_DUP))
-                        break;
-                memcpy((u8 *)out_cmd + cmd_pos, cmd->data[i], cmd->len[i]);
-                cmd_pos += cmd->len[i];
+
+                /* need at least IWL_HCMD_MIN_COPY_SIZE copied */
+                if (copy_size < IWL_HCMD_MIN_COPY_SIZE) {
+                        copy = IWL_HCMD_MIN_COPY_SIZE - copy_size;
+
+                        if (copy > cmd->len[i])
+                                copy = cmd->len[i];
+                }
+
+                /* copy everything if not nocopy/dup */
+                if (!(cmd->dataflags[i] & (IWL_HCMD_DFL_NOCOPY |
+                                           IWL_HCMD_DFL_DUP)))
+                        copy = cmd->len[i];
+
+                if (copy) {
+                        memcpy((u8 *)out_cmd + cmd_pos, cmd->data[i], copy);
+                        cmd_pos += copy;
+                        copy_size += copy;
+                }
         }
 
         WARN_ON_ONCE(txq->entries[idx].copy_cmd);
@@ -1275,7 +1309,14 @@ static int iwl_pcie_enqueue_hcmd(struct iwl_trans *trans,
                      out_cmd->hdr.cmd, le16_to_cpu(out_cmd->hdr.sequence),
                      cmd_size, q->write_ptr, idx, trans_pcie->cmd_queue);
 
-        phys_addr = dma_map_single(trans->dev, &out_cmd->hdr, copy_size,
+        /*
+         * If the entire command is smaller than IWL_HCMD_MIN_COPY_SIZE, we must
+         * still map at least that many bytes for the hardware to write back to.
+         * We have enough space, so that's not a problem.
+         */
+        dma_size = max_t(u16, copy_size, IWL_HCMD_MIN_COPY_SIZE);
+
+        phys_addr = dma_map_single(trans->dev, &out_cmd->hdr, dma_size,
                                    DMA_BIDIRECTIONAL);
         if (unlikely(dma_mapping_error(trans->dev, phys_addr))) {
                 idx = -ENOMEM;
@@ -1283,14 +1324,15 @@ static int iwl_pcie_enqueue_hcmd(struct iwl_trans *trans,
         }
 
         dma_unmap_addr_set(out_meta, mapping, phys_addr);
-        dma_unmap_len_set(out_meta, len, copy_size);
+        dma_unmap_len_set(out_meta, len, dma_size);
 
         iwl_pcie_txq_build_tfd(trans, txq, phys_addr, copy_size, 1);
 
+        /* map the remaining (adjusted) nocopy/dup fragments */
         for (i = 0; i < IWL_MAX_CMD_TFDS; i++) {
-                const void *data = cmd->data[i];
+                const void *data = cmddata[i];
 
-                if (!cmd->len[i])
+                if (!cmdlen[i])
                         continue;
                 if (!(cmd->dataflags[i] & (IWL_HCMD_DFL_NOCOPY |
                                            IWL_HCMD_DFL_DUP)))
@@ -1298,7 +1340,7 @@ static int iwl_pcie_enqueue_hcmd(struct iwl_trans *trans,
                 if (cmd->dataflags[i] & IWL_HCMD_DFL_DUP)
                         data = dup_buf;
                 phys_addr = dma_map_single(trans->dev, (void *)data,
-                                           cmd->len[i], DMA_BIDIRECTIONAL);
+                                           cmdlen[i], DMA_BIDIRECTIONAL);
                 if (dma_mapping_error(trans->dev, phys_addr)) {
                         iwl_pcie_tfd_unmap(trans, out_meta,
                                            &txq->tfds[q->write_ptr],
@@ -1307,7 +1349,7 @@ static int iwl_pcie_enqueue_hcmd(struct iwl_trans *trans,
                         goto out;
                 }
 
-                iwl_pcie_txq_build_tfd(trans, txq, phys_addr, cmd->len[i], 0);
+                iwl_pcie_txq_build_tfd(trans, txq, phys_addr, cmdlen[i], 0);
         }
 
         out_meta->flags = cmd->flags;
@@ -1317,8 +1359,7 @@ static int iwl_pcie_enqueue_hcmd(struct iwl_trans *trans,
 
         txq->need_update = 1;
 
-        trace_iwlwifi_dev_hcmd(trans->dev, cmd, cmd_size,
-                               &out_cmd->hdr, copy_size);
+        trace_iwlwifi_dev_hcmd(trans->dev, cmd, cmd_size, &out_cmd->hdr);
 
         /* start timer if queue currently empty */
         if (q->read_ptr == q->write_ptr && trans_pcie->wd_timeout)