From 69853123c513cf478992ca44e8a39afd651811a9 Mon Sep 17 00:00:00 2001 From: Andre Przywara Date: Mon, 6 Jul 2020 01:40:37 +0100 Subject: [PATCH] net: sun8i_emac: Improve cache maintenance on RX descriptor init Before we initialise the RX descriptors, there is no need to *clean* them from the cache, as we touch them for the first time. However we should cover the case that those buffers contain dirty cache lines, which could be evicted and written back to DRAM any time later, in the worst case *after* the MAC has transferred a packet into them. Signed-off-by: Andre Przywara Acked-by: Maxime Ripard Tested-by: Amit Singh Tomar # Pine64+ Reviewed-by: Jagan Teki --- drivers/net/sun8i_emac.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/net/sun8i_emac.c b/drivers/net/sun8i_emac.c index 7144f96aa3..c567b9e082 100644 --- a/drivers/net/sun8i_emac.c +++ b/drivers/net/sun8i_emac.c @@ -383,16 +383,21 @@ static void rx_descs_init(struct emac_eth_dev *priv) struct emac_dma_desc *desc_p; u32 idx; - /* flush Rx buffers */ - flush_dcache_range((uintptr_t)rxbuffs, (ulong)rxbuffs + - RX_TOTAL_BUFSIZE); + /* + * Make sure we don't have dirty cache lines around, which could + * be cleaned to DRAM *after* the MAC has already written data to it. + */ + invalidate_dcache_range((uintptr_t)desc_table_p, + (uintptr_t)desc_table_p + sizeof(priv->rx_chain)); + invalidate_dcache_range((uintptr_t)rxbuffs, + (uintptr_t)rxbuffs + sizeof(priv->rxbuffer)); for (idx = 0; idx < CONFIG_RX_DESCR_NUM; idx++) { desc_p = &desc_table_p[idx]; desc_p->buf_addr = (uintptr_t)&rxbuffs[idx * CONFIG_ETH_BUFSIZE] ; desc_p->next = (uintptr_t)&desc_table_p[idx + 1]; - desc_p->ctl_size |= CONFIG_ETH_RXSIZE; + desc_p->ctl_size = CONFIG_ETH_RXSIZE; desc_p->status = EMAC_DESC_OWN_DMA; }