diff options
Diffstat (limited to 'drivers/net/can/spi/mcp251xfd/mcp251xfd-ram.c')
| -rw-r--r-- | drivers/net/can/spi/mcp251xfd/mcp251xfd-ram.c | 153 |
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; + } +} |