[dpdk-dev] [PATCH v2 30/36] net/ice/base: discover and store size of available flash

[Qi Zhang]

When reading from the NVM using a flat address, it is useful to know the
upper bound on the size of the flash contents. This value is not stored
within the NVM.

We can determine the size by performing a bisection between upper and
lower bounds. It is known that the size cannot exceed 16 MB (offset of
0xFFFFFF).

Use a while loop to bisect the upper and lower bounds by reading one
byte at a time. On a failed read, lower the maximum bound. On
a successful read, increase the lower bound.

Save this as the flash_size in the ice_nvm_info structure that contains
data related to the NVM.

Signed-off-by: Jacob Keller <jacob.e.keller at intel.com>
Signed-off-by: Paul M Stillwell Jr <paul.m.stillwell.jr at intel.com>
Signed-off-by: Qi Zhang <qi.z.zhang at intel.com>
---
 drivers/net/ice/base/ice_nvm.c  | 61 +++++++++++++++++++++++++++++++++++++++++
 drivers/net/ice/base/ice_type.h |  1 +
 2 files changed, 62 insertions(+)

diff --git a/drivers/net/ice/base/ice_nvm.c b/drivers/net/ice/base/ice_nvm.c
index 51915cb7c..1bbd6e209 100644
--- a/drivers/net/ice/base/ice_nvm.c
+++ b/drivers/net/ice/base/ice_nvm.c
@@ -357,6 +357,60 @@ static enum ice_status ice_get_orom_ver_info(struct ice_hw *hw)
 }
 
 /**
+ * ice_discover_flash_size - Discover the available flash size.
+ * @hw: pointer to the HW struct
+ *
+ * The device flash could be up to 16MB in size. However, it is possible that
+ * the actual size is smaller. Use bisection to determine the accessible size
+ * of flash memory.
+ */
+static enum ice_status ice_discover_flash_size(struct ice_hw *hw)
+{
+	u32 min_size = 0, max_size = ICE_AQC_NVM_MAX_OFFSET + 1;
+	enum ice_status status;
+
+	ice_debug(hw, ICE_DBG_TRACE, "%s\n", __func__);
+
+	status = ice_acquire_nvm(hw, ICE_RES_READ);
+	if (status)
+		return status;
+
+	while ((max_size - min_size) > 1) {
+		u32 offset = (max_size + min_size) / 2;
+		u32 len = 1;
+		u8 data;
+
+		status = ice_read_flat_nvm(hw, offset, &len, &data, false);
+		if (status == ICE_ERR_AQ_ERROR &&
+		    hw->adminq.sq_last_status == ICE_AQ_RC_EINVAL) {
+			ice_debug(hw, ICE_DBG_NVM,
+				  "%s: New upper bound of %u bytes\n",
+				  __func__, offset);
+			status = ICE_SUCCESS;
+			max_size = offset;
+		} else if (!status) {
+			ice_debug(hw, ICE_DBG_NVM,
+				  "%s: New lower bound of %u bytes\n",
+				  __func__, offset);
+			min_size = offset;
+		} else {
+			/* an unexpected error occurred */
+			goto err_read_flat_nvm;
+		}
+	}
+
+	ice_debug(hw, ICE_DBG_NVM,
+		  "Predicted flash size is %u bytes\n", max_size);
+
+	hw->nvm.flash_size = max_size;
+
+err_read_flat_nvm:
+	ice_release_nvm(hw);
+
+	return status;
+}
+
+/**
  * ice_init_nvm - initializes NVM setting
  * @hw: pointer to the HW struct
  *
@@ -416,6 +470,13 @@ enum ice_status ice_init_nvm(struct ice_hw *hw)
 
 	nvm->eetrack = (eetrack_hi << 16) | eetrack_lo;
 
+	status = ice_discover_flash_size(hw);
+	if (status) {
+		ice_debug(hw, ICE_DBG_NVM,
+			  "NVM init error: failed to discover flash size.\n");
+		return status;
+	}
+
 	switch (hw->device_id) {
 	/* the following devices do not have boot_cfg_tlv yet */
 	case ICE_DEV_ID_E822C_BACKPLANE:
diff --git a/drivers/net/ice/base/ice_type.h b/drivers/net/ice/base/ice_type.h
index c14188f4c..9ee0d405f 100644
--- a/drivers/net/ice/base/ice_type.h
+++ b/drivers/net/ice/base/ice_type.h
@@ -492,6 +492,7 @@ struct ice_nvm_info {
 	struct ice_orom_info orom;	/* Option ROM version info */
 	u32 eetrack;			/* NVM data version */
 	u16 sr_words;			/* Shadow RAM size in words */
+	u32 flash_size;			/* Size of available flash in bytes */
 	u8 major_ver;			/* major version of dev starter */
 	u8 minor_ver;			/* minor version of dev starter */
 	u8 blank_nvm_mode;		/* is NVM empty (no FW present)*/
-- 
2.13.6