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Diffstat (limited to 'drivers/net/can/spi/mcp251xfd/mcp251xfd-ram.c')
-rw-r--r--drivers/net/can/spi/mcp251xfd/mcp251xfd-ram.c153
1 files changed, 153 insertions, 0 deletions
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-ram.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-ram.c
new file mode 100644
index 000000000..9e8e82cdb
--- /dev/null
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-ram.c
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// mcp251xfd - Microchip MCP251xFD Family CAN controller driver
+//
+// Copyright (c) 2021, 2022 Pengutronix,
+// Marc Kleine-Budde <kernel@pengutronix.de>
+//
+
+#include "mcp251xfd-ram.h"
+
+static inline u8 can_ram_clamp(const struct can_ram_config *config,
+ const struct can_ram_obj_config *obj,
+ u8 val)
+{
+ u8 max;
+
+ max = min_t(u8, obj->max, obj->fifo_num * config->fifo_depth);
+ return clamp(val, obj->min, max);
+}
+
+static u8
+can_ram_rounddown_pow_of_two(const struct can_ram_config *config,
+ const struct can_ram_obj_config *obj,
+ const u8 coalesce, u8 val)
+{
+ u8 fifo_num = obj->fifo_num;
+ u8 ret = 0, i;
+
+ val = can_ram_clamp(config, obj, val);
+
+ if (coalesce) {
+ /* Use 1st FIFO for coalescing, if requested.
+ *
+ * Either use complete FIFO (and FIFO Full IRQ) for
+ * coalescing or only half of FIFO (FIFO Half Full
+ * IRQ) and use remaining half for normal objects.
+ */
+ ret = min_t(u8, coalesce * 2, config->fifo_depth);
+ val -= ret;
+ fifo_num--;
+ }
+
+ for (i = 0; i < fifo_num && val; i++) {
+ u8 n;
+
+ n = min_t(u8, rounddown_pow_of_two(val),
+ config->fifo_depth);
+
+ /* skip small FIFOs */
+ if (n < obj->fifo_depth_min)
+ return ret;
+
+ ret += n;
+ val -= n;
+ }
+
+ return ret;
+}
+
+void can_ram_get_layout(struct can_ram_layout *layout,
+ const struct can_ram_config *config,
+ const struct ethtool_ringparam *ring,
+ const struct ethtool_coalesce *ec,
+ const bool fd_mode)
+{
+ u8 num_rx, num_tx;
+ u16 ram_free;
+
+ /* default CAN */
+
+ num_tx = config->tx.def[fd_mode];
+ num_tx = can_ram_rounddown_pow_of_two(config, &config->tx, 0, num_tx);
+
+ ram_free = config->size;
+ ram_free -= config->tx.size[fd_mode] * num_tx;
+
+ num_rx = ram_free / config->rx.size[fd_mode];
+
+ layout->default_rx = can_ram_rounddown_pow_of_two(config, &config->rx, 0, num_rx);
+ layout->default_tx = num_tx;
+
+ /* MAX CAN */
+
+ ram_free = config->size;
+ ram_free -= config->tx.size[fd_mode] * config->tx.min;
+ num_rx = ram_free / config->rx.size[fd_mode];
+
+ ram_free = config->size;
+ ram_free -= config->rx.size[fd_mode] * config->rx.min;
+ num_tx = ram_free / config->tx.size[fd_mode];
+
+ layout->max_rx = can_ram_rounddown_pow_of_two(config, &config->rx, 0, num_rx);
+ layout->max_tx = can_ram_rounddown_pow_of_two(config, &config->tx, 0, num_tx);
+
+ /* cur CAN */
+
+ if (ring) {
+ u8 num_rx_coalesce = 0, num_tx_coalesce = 0;
+
+ num_rx = can_ram_rounddown_pow_of_two(config, &config->rx, 0, ring->rx_pending);
+
+ /* The ethtool doc says:
+ * To disable coalescing, set usecs = 0 and max_frames = 1.
+ */
+ if (ec && !(ec->rx_coalesce_usecs_irq == 0 &&
+ ec->rx_max_coalesced_frames_irq == 1)) {
+ u8 max;
+
+ /* use only max half of available objects for coalescing */
+ max = min_t(u8, num_rx / 2, config->fifo_depth);
+ num_rx_coalesce = clamp(ec->rx_max_coalesced_frames_irq,
+ (u32)config->rx.fifo_depth_coalesce_min,
+ (u32)max);
+ num_rx_coalesce = rounddown_pow_of_two(num_rx_coalesce);
+
+ num_rx = can_ram_rounddown_pow_of_two(config, &config->rx,
+ num_rx_coalesce, num_rx);
+ }
+
+ ram_free = config->size - config->rx.size[fd_mode] * num_rx;
+ num_tx = ram_free / config->tx.size[fd_mode];
+ num_tx = min_t(u8, ring->tx_pending, num_tx);
+ num_tx = can_ram_rounddown_pow_of_two(config, &config->tx, 0, num_tx);
+
+ /* The ethtool doc says:
+ * To disable coalescing, set usecs = 0 and max_frames = 1.
+ */
+ if (ec && !(ec->tx_coalesce_usecs_irq == 0 &&
+ ec->tx_max_coalesced_frames_irq == 1)) {
+ u8 max;
+
+ /* use only max half of available objects for coalescing */
+ max = min_t(u8, num_tx / 2, config->fifo_depth);
+ num_tx_coalesce = clamp(ec->tx_max_coalesced_frames_irq,
+ (u32)config->tx.fifo_depth_coalesce_min,
+ (u32)max);
+ num_tx_coalesce = rounddown_pow_of_two(num_tx_coalesce);
+
+ num_tx = can_ram_rounddown_pow_of_two(config, &config->tx,
+ num_tx_coalesce, num_tx);
+ }
+
+ layout->cur_rx = num_rx;
+ layout->cur_tx = num_tx;
+ layout->rx_coalesce = num_rx_coalesce;
+ layout->tx_coalesce = num_tx_coalesce;
+ } else {
+ layout->cur_rx = layout->default_rx;
+ layout->cur_tx = layout->default_tx;
+ layout->rx_coalesce = 0;
+ layout->tx_coalesce = 0;
+ }
+}