net: macb: Shorten max_tx_len to 4KiB - 56 on mpfs

On mpfs, with SRAM configured for 4 queues, setting max_tx_len
to GEM_TX_MAX_LEN=0x3f0 results multiple AMBA errors.
Setting max_tx_len to (4KiB - 56) removes those errors.

The details are described in erratum 1686 by Cadence

The max jumbo frame size is also reduced for mpfs to (4KiB - 56).

Signed-off-by: Daire McNamara <daire.mcnamara@microchip.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
index cfbdd00..b6d5bf8 100644 (file)
--- a/drivers/net/ethernet/cadence/macb.h
+++ b/drivers/net/ethernet/cadence/macb.h
@@ -1181,6 +1181,7 @@ struct macb_config {
                            struct clk **hclk, struct clk **tx_clk,
                            struct clk **rx_clk, struct clk **tsu_clk);
        int     (*init)(struct platform_device *pdev);
+       unsigned int            max_tx_length;
        int     jumbo_max_len;
        const struct macb_usrio_config *usrio;
 };

diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index 29a1199..50a4b04 100644 (file)
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -4117,14 +4117,12 @@ static int macb_init(struct platform_device *pdev)
 
        /* setup appropriated routines according to adapter type */
        if (macb_is_gem(bp)) {
-               bp->max_tx_length = GEM_MAX_TX_LEN;
                bp->macbgem_ops.mog_alloc_rx_buffers = gem_alloc_rx_buffers;
                bp->macbgem_ops.mog_free_rx_buffers = gem_free_rx_buffers;
                bp->macbgem_ops.mog_init_rings = gem_init_rings;
                bp->macbgem_ops.mog_rx = gem_rx;
                dev->ethtool_ops = &gem_ethtool_ops;
        } else {
-               bp->max_tx_length = MACB_MAX_TX_LEN;
                bp->macbgem_ops.mog_alloc_rx_buffers = macb_alloc_rx_buffers;
                bp->macbgem_ops.mog_free_rx_buffers = macb_free_rx_buffers;
                bp->macbgem_ops.mog_init_rings = macb_init_rings;
@@ -4861,7 +4859,8 @@ static const struct macb_config mpfs_config = {
        .clk_init = macb_clk_init,
        .init = init_reset_optional,
        .usrio = &macb_default_usrio,
-       .jumbo_max_len = 10240,
+       .max_tx_length = 4040, /* Cadence Erratum 1686 */
+       .jumbo_max_len = 4040,
 };
 
 static const struct macb_config sama7g5_gem_config = {
@@ -5012,6 +5011,13 @@ static int macb_probe(struct platform_device *pdev)
        if (macb_config)
                bp->jumbo_max_len = macb_config->jumbo_max_len;
 
+       if (!hw_is_gem(bp->regs, bp->native_io))
+               bp->max_tx_length = MACB_MAX_TX_LEN;
+       else if (macb_config->max_tx_length)
+               bp->max_tx_length = macb_config->max_tx_length;
+       else
+               bp->max_tx_length = GEM_MAX_TX_LEN;
+
        bp->wol = 0;
        if (of_property_read_bool(np, "magic-packet"))
                bp->wol |= MACB_WOL_HAS_MAGIC_PACKET;