-----Original Message-----
From: Florian Fainelli <f.fainelli@gmail.com>
Sent: 2021年1月12日 1:30
To: Joakim Zhang <redacted>; peppe.cavallaro@st.com;
alexandre.torgue@st.com; joabreu@synopsys.com; davem@davemloft.net;
kuba@kernel.org
Cc: netdev@vger.kernel.org; dl-linux-imx <redacted>
Subject: Re: [PATCH 4/6] ethernet: stmmac: fix dma physical address of
descriptor when display ring

On 1/11/21 3:35 AM, Joakim Zhang wrote:

quoted

Driver uses dma_alloc_coherent to allocate dma memory for descriptors,
dma_alloc_coherent will return both the virtual address and physical
address. AFAIK, virt_to_phys could not convert virtual address to
physical address, for which memory is allocated by dma_alloc_coherent.

Signed-off-by: Joakim Zhang <redacted>
---
 .../ethernet/stmicro/stmmac/dwmac4_descs.c    |  5 +-
 .../net/ethernet/stmicro/stmmac/enh_desc.c    |  5 +-
 drivers/net/ethernet/stmicro/stmmac/hwif.h    |  3 +-
 .../net/ethernet/stmicro/stmmac/norm_desc.c   |  5 +-
 .../net/ethernet/stmicro/stmmac/stmmac_main.c | 50
++++++++++++-------
 5 files changed, 44 insertions(+), 24 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c

b/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
index c6540b003b43..8e1ee33ba1e6 100644

--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c

@@ -402,7 +402,8 @@ static void dwmac4_rd_set_tx_ic(struct dma_desc

*p)

quoted

 	p->des2 |= cpu_to_le32(TDES2_INTERRUPT_ON_COMPLETION);
 }

-static void dwmac4_display_ring(void *head, unsigned int size, bool
rx)
+static void dwmac4_display_ring(void *head, unsigned int size, bool rx,
+				unsigned int dma_rx_phy, unsigned int desc_size)
 {
 	struct dma_desc *p = (struct dma_desc *)head;
 	int i;

@@ -411,7 +412,7 @@ static void dwmac4_display_ring(void *head,

unsigned int size, bool rx)

 	for (i = 0; i < size; i++) {
 		pr_info("%03d [0x%x]: 0x%x 0x%x 0x%x 0x%x\n",
-			i, (unsigned int)virt_to_phys(p),
+			i, (unsigned int)(dma_rx_phy + i * desc_size),

This code will probably not work correctly on a machine with physical addresses
greater than 32-bit anyway and the address bits would be truncated then,
cannot you use a phy_addr_t or dma_addr_t and use %pa as far as the printk
format goes?

Thanks, I will fix it.

Best Regards,
Joakim Zhang

--
Florian