RE: [EXT] Re: [PATCH RFC net-next 03/19] net: mvpp2: add CM3 SRAM memory map

-----Original Message-----
From: Andrew Lunn <andrew@lunn.ch>
Sent: Sunday, January 10, 2021 7:05 PM
To: Stefan Chulski <redacted>
Cc: netdev@vger.kernel.org; thomas.petazzoni@bootlin.com;
davem@davemloft.net; Nadav Haklai [off-list ref]; Yan Markman
[off-list ref]; linux-kernel@vger.kernel.org; kuba@kernel.org;
linux@armlinux.org.uk; mw@semihalf.com; rmk+kernel@armlinux.org.uk;
atenart@kernel.org
Subject: [EXT] Re: [PATCH RFC net-next 03/19] net: mvpp2: add CM3 SRAM
memory map

External Email

----------------------------------------------------------------------

quoted

+static int mvpp2_get_sram(struct platform_device *pdev,
+			  struct mvpp2 *priv)
+{
+	struct device_node *dn = pdev->dev.of_node;
+	struct resource *res;
+
+	if (has_acpi_companion(&pdev->dev)) {
+		res = platform_get_resource(pdev, IORESOURCE_MEM, 2);
+		if (!res) {
+			dev_warn(&pdev->dev, "ACPI is too old, TX FC

disabled\n");

quoted

+			return 0;
+		}
+		priv->cm3_base = devm_ioremap_resource(&pdev->dev,

res);

quoted

+		if (IS_ERR(priv->cm3_base))
+			return PTR_ERR(priv->cm3_base);
+	} else {
+		priv->sram_pool = of_gen_pool_get(dn, "cm3-mem", 0);
+		if (!priv->sram_pool) {
+			dev_warn(&pdev->dev, "DT is too old, TX FC

disabled\n");

quoted

+			return 0;
+		}
+		priv->cm3_base = (void __iomem *)gen_pool_alloc(priv-
sram_pool,
+

	MSS_SRAM_SIZE);

quoted

+		if (!priv->cm3_base)
+			return -ENOMEM;

Should there be -EPROBE_DEFER handling in here somewhere? The SRAM is a
device, so it might not of been probed yet?

No, firmware probed during bootloader boot and we can use SRAM. SRAM memory can be safely used. 

Regards.