Commit 3af4b40b authored by Jacob Keller's avatar Jacob Keller Committed by Jakub Kicinski
Browse files

ice: implement direct read for NVM and Shadow RAM regions 



Implement the .read handler for the NVM and Shadow RAM regions. This
enables user space to read a small chunk of the flash without needing the
overhead of creating a full snapshot.

Update the documentation for ice to detail which regions have direct read
support.

Signed-off-by: default avatarJacob Keller <jacob.e.keller@intel.com>
Acked-by: default avatarJakub Kicinski <kuba@kernel.org>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 2d019784

Documentation/networking/devlink/ice.rst

+6 −2
Original line number Diff line number Diff line
@@ -198,8 +198,12 @@ device data. 
      - The contents of the device firmware's capabilities buffer. Useful to

        determine the current state and configuration of the device.



Users can request an immediate capture of a snapshot via the

``DEVLINK_CMD_REGION_NEW``

Both the ``nvm-flash`` and ``shadow-ram`` regions can be accessed without a

snapshot. The ``device-caps`` region requires a snapshot as the contents are

sent by firmware and can't be split into separate reads.



Users can request an immediate capture of a snapshot for all three regions

via the ``DEVLINK_CMD_REGION_NEW`` command.



.. code:: shell

drivers/net/ethernet/intel/ice/ice_devlink.c

+69 −0
Original line number Diff line number Diff line
@@ -1687,6 +1687,73 @@ static int ice_devlink_nvm_snapshot(struct devlink *devlink, 
	return 0;

}



/**

 * ice_devlink_nvm_read - Read a portion of NVM flash contents

 * @devlink: the devlink instance

 * @ops: the devlink region to snapshot

 * @extack: extended ACK response structure

 * @offset: the offset to start at

 * @size: the amount to read

 * @data: the data buffer to read into

 *

 * This function is called in response to DEVLINK_CMD_REGION_READ to directly

 * read a section of the NVM contents.

 *

 * It reads from either the nvm-flash or shadow-ram region contents.

 *

 * @returns zero on success, and updates the data pointer. Returns a non-zero

 * error code on failure.

 */

static int ice_devlink_nvm_read(struct devlink *devlink,

				const struct devlink_region_ops *ops,

				struct netlink_ext_ack *extack,

				u64 offset, u32 size, u8 *data)

{

	struct ice_pf *pf = devlink_priv(devlink);

	struct device *dev = ice_pf_to_dev(pf);

	struct ice_hw *hw = &pf->hw;

	bool read_shadow_ram;

	u64 nvm_size;

	int status;



	if (ops == &ice_nvm_region_ops) {

		read_shadow_ram = false;

		nvm_size = hw->flash.flash_size;

	} else if (ops == &ice_sram_region_ops) {

		read_shadow_ram = true;

		nvm_size = hw->flash.sr_words * 2u;

	} else {

		NL_SET_ERR_MSG_MOD(extack, "Unexpected region in snapshot function");

		return -EOPNOTSUPP;

	}



	if (offset + size >= nvm_size) {

		NL_SET_ERR_MSG_MOD(extack, "Cannot read beyond the region size");

		return -ERANGE;

	}



	status = ice_acquire_nvm(hw, ICE_RES_READ);

	if (status) {

		dev_dbg(dev, "ice_acquire_nvm failed, err %d aq_err %d\n",

			status, hw->adminq.sq_last_status);

		NL_SET_ERR_MSG_MOD(extack, "Failed to acquire NVM semaphore");

		return -EIO;

	}



	status = ice_read_flat_nvm(hw, (u32)offset, &size, data,

				   read_shadow_ram);

	if (status) {

		dev_dbg(dev, "ice_read_flat_nvm failed after reading %u bytes, err %d aq_err %d\n",

			size, status, hw->adminq.sq_last_status);

		NL_SET_ERR_MSG_MOD(extack, "Failed to read NVM contents");

		ice_release_nvm(hw);

		return -EIO;

	}

	ice_release_nvm(hw);



	return 0;

}



/**

 * ice_devlink_devcaps_snapshot - Capture snapshot of device capabilities

 * @devlink: the devlink instance
@@ -1735,12 +1802,14 @@ static const struct devlink_region_ops ice_nvm_region_ops = { 
	.name = "nvm-flash",

	.destructor = vfree,

	.snapshot = ice_devlink_nvm_snapshot,

	.read = ice_devlink_nvm_read,

};



static const struct devlink_region_ops ice_sram_region_ops = {

	.name = "shadow-ram",

	.destructor = vfree,

	.snapshot = ice_devlink_nvm_snapshot,

	.read = ice_devlink_nvm_read,

};



static const struct devlink_region_ops ice_devcaps_region_ops = {