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// 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;
}
}
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