[ndctl PATCH 6/8] libndctl,papr_scm: Implement scaffolding to issue and handle DSM cmds

[Vaibhav Jain <vaibhav@linux.ibm.com>]

This patch implement necessary infrastructure inside 'papr_scm.c' to
issue and handle DSM commands. Changed implemented are:

* Implement dimm initialization/un-initialization functions
  papr_dimm_init()/unint() to allocate a per-dimm 'struct dimm_priv'
  instance.

* New helper function allocate_cmd() to allocate command packages for
  a specific DSM command and payload size.

* New function update_dimm_state() to parse a given command payload
  and update per dimm 'struct dimm_priv'.

* Provide an implementation of 'dimm_ops->smart_get_flags' to send the
  submitted instance of 'struct ndctl_cmd' to update_dimm_state().

* Logging helpers for papr_scm that use the underlying libndctl
  provided logging.

Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
---
 ndctl/lib/papr_scm.c | 174 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 174 insertions(+)

diff --git a/ndctl/lib/papr_scm.c b/ndctl/lib/papr_scm.c
index 878698a5a8b4..0a3857e2a4c4 100644
--- a/ndctl/lib/papr_scm.c
+++ b/ndctl/lib/papr_scm.c
@@ -20,6 +20,29 @@
 #include <lib/private.h>
 #include <papr_scm_dsm.h>
 
+/* Utility logging maros for simplify logging */
+#define PAPR_DBG(_dimm_, _format_str_, ...) dbg(_dimm_->bus->ctx,	\
+					      "papr_scm:"#_format_str_,	\
+					      ##__VA_ARGS__)
+#define PAPR_INFO(_dimm_, _format_str_, ...) info(_dimm_->bus->ctx,	\
+						"papr_scm:"#_format_str_, \
+						##__VA_ARGS__)
+#define PAPR_ERR(_dimm_, _format_str_, ...) err(_dimm_->bus->ctx,	\
+					      "papr_scm:"#_format_str_,	\
+					      ##__VA_ARGS__)
+#define PAPR_NOTICE(_dimm_, _format_str_, ...) notice(_dimm_->bus->ctx,	\
+						    "papr_scm:"#_format_str_, \
+						    ##__VA_ARGS__)
+
+/* Command flags to indicate if a given command is parsed of not */
+#define CMD_PKG_SUBMITTED 1
+#define CMD_PKG_PARSED 2
+
+/* Per dimm data. Holds per-dimm data parsed from the cmd_pkgs */
+struct dimm_priv {
+	/* Empty for now */
+};
+
 static bool papr_cmd_is_supported(struct ndctl_dimm *dimm, int cmd)
 {
 	/* Handle this separately to support monitor mode */
@@ -29,6 +52,157 @@ static bool papr_cmd_is_supported(struct ndctl_dimm *dimm, int cmd)
 	return !!(dimm->cmd_mask & (1ULL << cmd));
 }
 
+static __u64 pcmd_to_dsm(const struct nd_papr_scm_cmd_pkg *pcmd)
+{
+	return pcmd->hdr.nd_command;
+}
+
+/* Verify if the given command is supported and valid */
+static bool cmd_is_valid(struct ndctl_dimm *dimm, struct ndctl_cmd *cmd)
+{
+	const struct nd_papr_scm_cmd_pkg *pcmd = nd_to_papr_cmd_pkg(cmd->pkg);
+
+	if (dimm == NULL)
+		return false;
+
+	if (cmd == NULL) {
+		PAPR_ERR(dimm, "Invalid command\n");
+		return false;
+	}
+
+	/* Verify the command family */
+	if (pcmd->hdr.nd_family != NVDIMM_FAMILY_PAPR_SCM) {
+		PAPR_ERR(dimm, "Invalid command family:0x%016llx\n",
+			 pcmd->hdr.nd_family);
+		return false;
+	}
+
+	/* Verify the DSM */
+	if (pcmd_to_dsm(pcmd) <= DSM_PAPR_SCM_MIN ||
+	    pcmd_to_dsm(pcmd) >= DSM_PAPR_SCM_MAX) {
+		PAPR_ERR(dimm, "Invalid command :0x%016llx\n",
+			 pcmd->hdr.nd_command);
+		return false;
+	}
+
+	return true;
+}
+
+/* Parse a command payload and update dimm flags/private data */
+static int update_dimm_stats(struct ndctl_dimm *dimm, struct ndctl_cmd *cmd)
+{
+	const struct nd_papr_scm_cmd_pkg *pcmd;
+
+	if (!cmd_is_valid(dimm, cmd))
+		return -EINVAL;
+
+	/*
+	 * Silently prevent parsing of an already parsed ndctl_cmd else
+	 * mark the command as parsed.
+	 */
+	if (cmd->status >= CMD_PKG_PARSED) {
+		return 0;
+	} else if (cmd->status < 0) {
+		PAPR_ERR(dimm, "Command error %d\n", cmd->status);
+		return -ENXIO;
+	}
+
+	/* Mark the command as parsed */
+	cmd->status = CMD_PKG_PARSED;
+
+	/* Get the command dsm and handle it */
+	pcmd = nd_to_papr_cmd_pkg(cmd->pkg);
+	switch (pcmd_to_dsm(pcmd)) {
+	default:
+		PAPR_ERR(dimm, "Unhandled dsm-command 0x%016llx\n",
+			 pcmd_to_dsm(pcmd));
+		return -ENOENT;
+	}
+}
+
+/* Allocate a struct ndctl_cmd for given dsm command with payload size */
+static struct ndctl_cmd *allocate_cmd(struct ndctl_dimm *dimm,
+				      __u64 dsm_cmd, size_t payload_size,
+				      uint16_t payload_version)
+{
+	struct ndctl_cmd *cmd;
+	struct nd_papr_scm_cmd_pkg *pcmd;
+	size_t size;
+
+	size = sizeof(struct ndctl_cmd) +
+		sizeof(struct nd_papr_scm_cmd_pkg) + payload_size;
+	cmd = calloc(1, size);
+	if (!cmd)
+		return NULL;
+	pcmd = nd_to_papr_cmd_pkg(cmd->pkg);
+
+	ndctl_cmd_ref(cmd);
+	cmd->dimm = dimm;
+	cmd->type = ND_CMD_CALL;
+	cmd->size = size;
+	cmd->status = CMD_PKG_SUBMITTED;
+	cmd->firmware_status = (u32 *) &pcmd->cmd_status;
+
+	/* Populate the nd_cmd_pkg contained in nd_papr_scm_cmd_pkg */
+	pcmd->hdr.nd_family = NVDIMM_FAMILY_PAPR_SCM;
+	pcmd->hdr.nd_command = dsm_cmd;
+
+	pcmd->payload_version = payload_version;
+	pcmd->payload_offset = sizeof(struct nd_papr_scm_cmd_pkg);
+
+	/* Keep payload size empty. To be populated by called */
+	pcmd->hdr.nd_fw_size = 0;
+	pcmd->hdr.nd_size_out = 0;
+	pcmd->hdr.nd_size_in = 0;
+
+	return cmd;
+}
+
+static unsigned int papr_smart_get_flags(struct ndctl_cmd *cmd)
+{
+	/* In case of error return empty flags * */
+	if (update_dimm_stats(cmd->dimm, cmd))
+		return 0;
+
+	/* Return empty flags for now as no DSM support */
+	return 0;
+}
+
+static int papr_dimm_init(struct ndctl_dimm *dimm)
+{
+	struct dimm_priv *p;
+
+	if (dimm->dimm_user_data) {
+		PAPR_DBG(dimm, "Dimm already initialized !!\n");
+		return 0;
+	}
+
+	p = calloc(1, sizeof(struct dimm_priv));
+	if (!p) {
+		PAPR_ERR(dimm, "Unable to allocate memory for dimm-private\n");
+		return -1;
+	}
+
+	dimm->dimm_user_data = p;
+	return 0;
+}
+
+static void papr_dimm_uninit(struct ndctl_dimm *dimm)
+{
+	struct dimm_priv *p = dimm->dimm_user_data;
+
+	if (!p) {
+		PAPR_DBG(dimm, "Dimm already un-initialized !!\n");
+		return;
+	}
+
+	dimm->dimm_user_data = NULL;
+	free(p);
+}
+
 struct ndctl_dimm_ops * const papr_scm_dimm_ops = &(struct ndctl_dimm_ops) {
 	.cmd_is_supported = papr_cmd_is_supported,
+	.dimm_init = papr_dimm_init,
+	.dimm_uninit = papr_dimm_uninit,
+	.smart_get_flags = papr_smart_get_flags,
 };
-- 
2.24.1
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