[PATCH net-next 1/7] net/faraday: Separate rx page storage from rxdesc

From: Joel Stanley
Date: Tue Sep 20 2016 - 02:30:35 EST


From: Andrew Jeffery <andrew@xxxxxxxx>

The ftgmac100 hardware revision in e.g. the Aspeed AST2500 no longer
reserves all bits in RXDES#2 but instead uses the bottom 16 bits to
store MAC frame metadata. Avoid corruption by shifting struct page
pointers out to their own member in struct ftgmac100.

Signed-off-by: Andrew Jeffery <andrew@xxxxxxxx>
Signed-off-by: Joel Stanley <joel@xxxxxxxxx>
---
drivers/net/ethernet/faraday/ftgmac100.c | 25 ++++++++++++++++++-------
1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c
index 36361f8bf894..40622567159a 100644
--- a/drivers/net/ethernet/faraday/ftgmac100.c
+++ b/drivers/net/ethernet/faraday/ftgmac100.c
@@ -60,6 +60,8 @@ struct ftgmac100 {
struct ftgmac100_descs *descs;
dma_addr_t descs_dma_addr;

+ struct page *rx_pages[RX_QUEUE_ENTRIES];
+
unsigned int rx_pointer;
unsigned int tx_clean_pointer;
unsigned int tx_pointer;
@@ -341,18 +343,27 @@ static bool ftgmac100_rxdes_ipcs_err(struct ftgmac100_rxdes *rxdes)
return rxdes->rxdes1 & cpu_to_le32(FTGMAC100_RXDES1_IP_CHKSUM_ERR);
}

+static inline struct page **ftgmac100_rxdes_page_slot(struct ftgmac100 *priv,
+ struct ftgmac100_rxdes *rxdes)
+{
+ return &priv->rx_pages[rxdes - priv->descs->rxdes];
+}
+
/*
* rxdes2 is not used by hardware. We use it to keep track of page.
* Since hardware does not touch it, we can skip cpu_to_le32()/le32_to_cpu().
*/
-static void ftgmac100_rxdes_set_page(struct ftgmac100_rxdes *rxdes, struct page *page)
+static void ftgmac100_rxdes_set_page(struct ftgmac100 *priv,
+ struct ftgmac100_rxdes *rxdes,
+ struct page *page)
{
- rxdes->rxdes2 = (unsigned int)page;
+ *ftgmac100_rxdes_page_slot(priv, rxdes) = page;
}

-static struct page *ftgmac100_rxdes_get_page(struct ftgmac100_rxdes *rxdes)
+static struct page *ftgmac100_rxdes_get_page(struct ftgmac100 *priv,
+ struct ftgmac100_rxdes *rxdes)
{
- return (struct page *)rxdes->rxdes2;
+ return *ftgmac100_rxdes_page_slot(priv, rxdes);
}

/******************************************************************************
@@ -501,7 +512,7 @@ static bool ftgmac100_rx_packet(struct ftgmac100 *priv, int *processed)

do {
dma_addr_t map = ftgmac100_rxdes_get_dma_addr(rxdes);
- struct page *page = ftgmac100_rxdes_get_page(rxdes);
+ struct page *page = ftgmac100_rxdes_get_page(priv, rxdes);
unsigned int size;

dma_unmap_page(priv->dev, map, RX_BUF_SIZE, DMA_FROM_DEVICE);
@@ -779,7 +790,7 @@ static int ftgmac100_alloc_rx_page(struct ftgmac100 *priv,
return -ENOMEM;
}

- ftgmac100_rxdes_set_page(rxdes, page);
+ ftgmac100_rxdes_set_page(priv, rxdes, page);
ftgmac100_rxdes_set_dma_addr(rxdes, map);
ftgmac100_rxdes_set_dma_own(rxdes);
return 0;
@@ -791,7 +802,7 @@ static void ftgmac100_free_buffers(struct ftgmac100 *priv)

for (i = 0; i < RX_QUEUE_ENTRIES; i++) {
struct ftgmac100_rxdes *rxdes = &priv->descs->rxdes[i];
- struct page *page = ftgmac100_rxdes_get_page(rxdes);
+ struct page *page = ftgmac100_rxdes_get_page(priv, rxdes);
dma_addr_t map = ftgmac100_rxdes_get_dma_addr(rxdes);

if (!page)
--
2.9.3