[PATCH net 2/2] net/stmmac: Verify provided DTS AXI setup

[Jakub Raczynski]

During parsing of AXI setup, there are few issues:
- 'axi_blen' array is uninitialized value on stack without zero-init stack
  configured. This can result in random AXI burst length config if
  DTS config provides shorter array than AXI_BLEN.
  Fix this by initializing it to zero, which allows to provide shorter configs,
  which sometimes happens where only one value is used.

- stmmac_axi_blen_to_mask() is executed regardless of return of
  of_property_read_u32_array(). This is not issue after axi_blen is
  initialized to zero, as zero blen values are skipped in
  stmmac_axi_blen_to_mask(), but that would be useless operation.
  Fix it by checking return value of of_property_read_u32_array() and
  parse any legit config.

- In case of failed memory allocation for AXI and error, there is no handling
  of that. Fix it by checking if AXI config is error and return if so,
  as this can only lack of memory. No AXI config, although is probably
  wrong in most cases, is not treated as error, as generic config is mostly
  provided in drivers.

Fixes: afea03656add ("stmmac: rework DMA bus setting and introduce new platform AXI structure")
Reported-by: Sashiko AI <sashiko-bot at kernel.org>
Signed-off-by: Jakub Raczynski <j.raczynski at samsung.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
index 9112cd69b9b1..0acc61a98292 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
@@ -95,7 +95,7 @@ static struct stmmac_axi *stmmac_axi_setup(struct platform_device *pdev)
 {
 	struct device_node *np;
 	struct stmmac_axi *axi;
-	u32 axi_blen[AXI_BLEN];
+	u32 axi_blen[AXI_BLEN] = { 0 };
 
 	np = of_parse_phandle(pdev->dev.of_node, "snps,axi-config", 0);
 	if (!np)
@@ -115,8 +115,8 @@ static struct stmmac_axi *stmmac_axi_setup(struct platform_device *pdev)
 		axi->axi_wr_osr_lmt = 1;
 	if (of_property_read_u32(np, "snps,rd_osr_lmt", &axi->axi_rd_osr_lmt))
 		axi->axi_rd_osr_lmt = 1;
-	of_property_read_u32_array(np, "snps,blen", axi_blen, AXI_BLEN);
-	stmmac_axi_blen_to_mask(&axi->axi_blen_regval, axi_blen, AXI_BLEN);
+	if (!of_property_read_u32_array(np, "snps,blen", axi_blen, AXI_BLEN))
+		stmmac_axi_blen_to_mask(&axi->axi_blen_regval, axi_blen, AXI_BLEN);
 	of_node_put(np);
 
 	return axi;
@@ -580,6 +580,10 @@ stmmac_probe_config_dt(struct platform_device *pdev, u8 *mac)
 	of_property_read_u32(np, "snps,ps-speed", &plat->mac_port_sel_speed);
 
 	plat->axi = stmmac_axi_setup(pdev);
+	if (IS_ERR(plat->axi)) {
+		ret = plat->axi;
+		goto error_put_mdio;
+	}
 
 	rc = stmmac_mtl_setup(pdev, plat);
 	if (rc) {
-- 
2.34.1