ice: add ability to read and configure FW log data

Once logging is enabled the user should read the data from the 'data'
file. The data is in the form of a binary blob that can be sent to Intel
for decoding. To read the data use a command like:

  # cat /sys/kernel/debug/ice/0000\:18\:00.0/fwlog/data > log_data.bin

If the user wants to clear the FW log data that has been stored in the
driver then they can write any value to the 'data' file and that will clear
the data. An example is:

  # echo 34 > /sys/kernel/debug/ice/0000\:18\:00.0/fwlog/data

In addition to being able to read the data the user can configure how
much memory is used to store FW log data. This allows the user to
increase/decrease the amount of memory based on the users situation.
The data is stored such that if the memory fills up then the oldest data
will get overwritten in a circular manner. To change the amount of
memory the user can write to the 'log_size' file like this:

  # echo <value> > /sys/kernel/debug/ice/0000\:18\:00.0/fwlog/log_size

Where <value> is one of 128K, 256K, 512K, 1M, and 2M. The default value
is 1M.

The user can see the current value of 'log_size' by reading the file:

  # cat /sys/kernel/debug/ice/0000\:18\:00.0/fwlog/log_size

Signed-off-by: Paul M Stillwell Jr <paul.m.stillwell.jr@intel.com>
Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

1 files changed, 142 insertions, 0 deletions

diff --git a/drivers/net/ethernet/intel/ice/ice_fwlog.c b/drivers/net/ethernet/intel/ice/ice_fwlog.c
index 25a17cbc1d34..92b5dac481cd 100644
--- a/drivers/net/ethernet/intel/ice/ice_fwlog.c
+++ b/drivers/net/ethernet/intel/ice/ice_fwlog.c
@@ -1,10 +1,128 @@
 // SPDX-License-Identifier: GPL-2.0
 /* Copyright (c) 2022, Intel Corporation. */
 
+#include <linux/vmalloc.h>
 #include "ice.h"
 #include "ice_common.h"
 #include "ice_fwlog.h"
 
+bool ice_fwlog_ring_full(struct ice_fwlog_ring *rings)
+{
+	u16 head, tail;
+
+	head = rings->head;
+	tail = rings->tail;
+
+	if (head < tail && (tail - head == (rings->size - 1)))
+		return true;
+	else if (head > tail && (tail == (head - 1)))
+		return true;
+
+	return false;
+}
+
+bool ice_fwlog_ring_empty(struct ice_fwlog_ring *rings)
+{
+	return rings->head == rings->tail;
+}
+
+void ice_fwlog_ring_increment(u16 *item, u16 size)
+{
+	*item = (*item + 1) & (size - 1);
+}
+
+static int ice_fwlog_alloc_ring_buffs(struct ice_fwlog_ring *rings)
+{
+	int i, nr_bytes;
+	u8 *mem;
+
+	nr_bytes = rings->size * ICE_AQ_MAX_BUF_LEN;
+	mem = vzalloc(nr_bytes);
+	if (!mem)
+		return -ENOMEM;
+
+	for (i = 0; i < rings->size; i++) {
+		struct ice_fwlog_data *ring = &rings->rings[i];
+
+		ring->data_size = ICE_AQ_MAX_BUF_LEN;
+		ring->data = mem;
+		mem += ICE_AQ_MAX_BUF_LEN;
+	}
+
+	return 0;
+}
+
+static void ice_fwlog_free_ring_buffs(struct ice_fwlog_ring *rings)
+{
+	int i;
+
+	for (i = 0; i < rings->size; i++) {
+		struct ice_fwlog_data *ring = &rings->rings[i];
+
+		/* the first ring is the base memory for the whole range so
+		 * free it
+		 */
+		if (!i)
+			vfree(ring->data);
+
+		ring->data = NULL;
+		ring->data_size = 0;
+	}
+}
+
+#define ICE_FWLOG_INDEX_TO_BYTES(n) ((128 * 1024) << (n))
+/**
+ * ice_fwlog_realloc_rings - reallocate the FW log rings
+ * @hw: pointer to the HW structure
+ * @index: the new index to use to allocate memory for the log data
+ *
+ */
+void ice_fwlog_realloc_rings(struct ice_hw *hw, int index)
+{
+	struct ice_fwlog_ring ring;
+	int status, ring_size;
+
+	/* convert the number of bytes into a number of 4K buffers. externally
+	 * the driver presents the interface to the FW log data as a number of
+	 * bytes because that's easy for users to understand. internally the
+	 * driver uses a ring of buffers because the driver doesn't know where
+	 * the beginning and end of any line of log data is so the driver has
+	 * to overwrite data as complete blocks. when the data is returned to
+	 * the user the driver knows that the data is correct and the FW log
+	 * can be correctly parsed by the tools
+	 */
+	ring_size = ICE_FWLOG_INDEX_TO_BYTES(index) / ICE_AQ_MAX_BUF_LEN;
+	if (ring_size == hw->fwlog_ring.size)
+		return;
+
+	/* allocate space for the new rings and buffers then release the
+	 * old rings and buffers. that way if we don't have enough
+	 * memory then we at least have what we had before
+	 */
+	ring.rings = kcalloc(ring_size, sizeof(*ring.rings), GFP_KERNEL);
+	if (!ring.rings)
+		return;
+
+	ring.size = ring_size;
+
+	status = ice_fwlog_alloc_ring_buffs(&ring);
+	if (status) {
+		dev_warn(ice_hw_to_dev(hw), "Unable to allocate memory for FW log ring data buffers\n");
+		ice_fwlog_free_ring_buffs(&ring);
+		kfree(ring.rings);
+		return;
+	}
+
+	ice_fwlog_free_ring_buffs(&hw->fwlog_ring);
+	kfree(hw->fwlog_ring.rings);
+
+	hw->fwlog_ring.rings = ring.rings;
+	hw->fwlog_ring.size = ring.size;
+	hw->fwlog_ring.index = index;
+	hw->fwlog_ring.head = 0;
+	hw->fwlog_ring.tail = 0;
+}
+
 /**
  * ice_fwlog_init - Initialize FW logging configuration
  * @hw: pointer to the HW structure
@@ -28,6 +146,25 @@ int ice_fwlog_init(struct ice_hw *hw)
 		if (status)
 			return status;
 
+		hw->fwlog_ring.rings = kcalloc(ICE_FWLOG_RING_SIZE_DFLT,
+					       sizeof(*hw->fwlog_ring.rings),
+					       GFP_KERNEL);
+		if (!hw->fwlog_ring.rings) {
+			dev_warn(ice_hw_to_dev(hw), "Unable to allocate memory for FW log rings\n");
+			return -ENOMEM;
+		}
+
+		hw->fwlog_ring.size = ICE_FWLOG_RING_SIZE_DFLT;
+		hw->fwlog_ring.index = ICE_FWLOG_RING_SIZE_INDEX_DFLT;
+
+		status = ice_fwlog_alloc_ring_buffs(&hw->fwlog_ring);
+		if (status) {
+			dev_warn(ice_hw_to_dev(hw), "Unable to allocate memory for FW log ring data buffers\n");
+			ice_fwlog_free_ring_buffs(&hw->fwlog_ring);
+			kfree(hw->fwlog_ring.rings);
+			return status;
+		}
+
 		ice_debugfs_fwlog_init(hw->back);
 	} else {
 		dev_warn(ice_hw_to_dev(hw), "FW logging is not supported in this NVM image. Please update the NVM to get FW log support\n");
@@ -68,6 +205,11 @@ void ice_fwlog_deinit(struct ice_hw *hw)
 	if (status)
 		dev_warn(ice_hw_to_dev(hw), "Unable to unregister FW logging, status: %d\n",
 			 status);
+
+	if (hw->fwlog_ring.rings) {
+		ice_fwlog_free_ring_buffs(&hw->fwlog_ring);
+		kfree(hw->fwlog_ring.rings);
+	}
 }
 
 /**