[PATCH v3 2/6] pds_core: add support for identity version 2

["Nikhil P. Rao" <nikhil.rao@amd.com>]

From: Brett Creeley <brett.creeley@amd.com>

Add a new capabilities field in struct pds_core_dev_identity,
which requires bumping the identity version to 2, i.e.
PDS_CORE_IDENTITY_VERSION_2. If version 2 negotiation fails,
then quietly fall back to version 1. If version 1 negotiation
fails, then driver load will fail.

Another patch in the series will make use of the capabilities
field.

Signed-off-by: Brett Creeley <brett.creeley@amd.com>
---
 drivers/net/ethernet/amd/pds_core/dev.c | 39 ++++++++++++++++++++-----
 include/linux/pds/pds_core_if.h         |  4 +++
 2 files changed, 36 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/amd/pds_core/dev.c b/drivers/net/ethernet/amd/pds_core/dev.c
index dd9989cfe6b3..5c0ca3d0b000 100644
--- a/drivers/net/ethernet/amd/pds_core/dev.c
+++ b/drivers/net/ethernet/amd/pds_core/dev.c
@@ -250,15 +250,17 @@ int pdsc_devcmd_reset(struct pdsc *pdsc)
 	return pdsc_devcmd(pdsc, &cmd, &comp, pdsc->devcmd_timeout);
 }
 
-static int pdsc_devcmd_identify_locked(struct pdsc *pdsc)
+static int pdsc_devcmd_identify_locked(struct pdsc *pdsc, u8 drv_ident_ver,
+				       bool do_msg)
 {
 	union pds_core_dev_comp comp = {};
 	union pds_core_dev_cmd cmd = {
 		.identify.opcode = PDS_CORE_CMD_IDENTIFY,
-		.identify.ver = PDS_CORE_IDENTITY_VERSION_1,
+		.identify.ver = drv_ident_ver,
 	};
 
-	return pdsc_devcmd_locked(pdsc, &cmd, &comp, pdsc->devcmd_timeout);
+	return __pdsc_devcmd_locked(pdsc, &cmd, &comp, pdsc->devcmd_timeout,
+				    do_msg);
 }
 
 static void pdsc_init_devinfo(struct pdsc *pdsc)
@@ -281,8 +283,9 @@ static void pdsc_init_devinfo(struct pdsc *pdsc)
 	dev_dbg(pdsc->dev, "fw_version %s\n", pdsc->dev_info.fw_version);
 }
 
-static int pdsc_identify(struct pdsc *pdsc)
+static int pdsc_identify_ver(struct pdsc *pdsc, u8 drv_ident_ver)
 {
+	bool do_msg = drv_ident_ver == PDS_CORE_IDENTITY_VERSION_1;
 	struct pds_core_drv_identity drv = {};
 	size_t sz;
 	int err;
@@ -305,17 +308,24 @@ static int pdsc_identify(struct pdsc *pdsc)
 	sz = min_t(size_t, sizeof(drv), sizeof(pdsc->cmd_regs->data));
 	memcpy_toio(&pdsc->cmd_regs->data, &drv, sz);
 
-	err = pdsc_devcmd_identify_locked(pdsc);
+	err = pdsc_devcmd_identify_locked(pdsc, drv_ident_ver, do_msg);
 	if (!err) {
 		sz = min_t(size_t, sizeof(pdsc->dev_ident),
 			   sizeof(pdsc->cmd_regs->data));
 		memcpy_fromio(&pdsc->dev_ident, &pdsc->cmd_regs->data, sz);
+
+		/* V1 firmware doesn't set capabilities, so the field may
+		 * contain garbage from the outgoing driver identity.
+		 */
+		if (pdsc->dev_ident.version < PDS_CORE_IDENTITY_VERSION_2)
+			pdsc->dev_ident.capabilities = 0;
 	}
 	mutex_unlock(&pdsc->devcmd_lock);
 
 	if (err) {
-		dev_err(pdsc->dev, "Cannot identify device: %pe\n",
-			ERR_PTR(err));
+		if (do_msg)
+			dev_err(pdsc->dev, "Cannot identify device: %pe\n",
+				ERR_PTR(err));
 		return err;
 	}
 
@@ -334,6 +344,21 @@ static int pdsc_identify(struct pdsc *pdsc)
 	return 0;
 }
 
+static int pdsc_identify(struct pdsc *pdsc)
+{
+	int err;
+
+	/* Older firmware rejects anything but PDS_CORE_IDENTITY_VERSION_1
+	 * instead of returning the max supported identity version, so retry if
+	 * firmware doesn't support PDS_CORE_IDENTITY_VERSION_2
+	 */
+	err = pdsc_identify_ver(pdsc, PDS_CORE_IDENTITY_VERSION_2);
+	if (err)
+		err = pdsc_identify_ver(pdsc, PDS_CORE_IDENTITY_VERSION_1);
+
+	return err;
+}
+
 void pdsc_dev_uninit(struct pdsc *pdsc)
 {
 	if (pdsc->intr_info) {
diff --git a/include/linux/pds/pds_core_if.h b/include/linux/pds/pds_core_if.h
index 17a87c1a55d7..619186f26b5b 100644
--- a/include/linux/pds/pds_core_if.h
+++ b/include/linux/pds/pds_core_if.h
@@ -119,6 +119,8 @@ struct pds_core_drv_identity {
  *		      value in usecs to device units using:
  *		      device units = usecs * mult / div
  * @vif_types:        How many of each VIF device type is supported
+ * @capabilities:     Device capabilities
+ *		      only supported on version >= PDS_CORE_IDENTITY_VERSION_2
  */
 struct pds_core_dev_identity {
 	u8     version;
@@ -131,9 +133,11 @@ struct pds_core_dev_identity {
 	__le32 intr_coal_mult;
 	__le32 intr_coal_div;
 	__le16 vif_types[PDS_DEV_TYPE_MAX];
+	__le64 capabilities;
 };
 
 #define PDS_CORE_IDENTITY_VERSION_1	1
+#define PDS_CORE_IDENTITY_VERSION_2	2
 
 /**
  * struct pds_core_dev_identify_cmd - Driver/device identify command
-- 
2.43.0