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

[Stefan Chulski <stefanc@marvell.com>]

> -----Original Message-----
> From: Andrew Lunn <andrew@lunn.ch>
> Sent: Sunday, January 10, 2021 7:05 PM
> To: Stefan Chulski <stefanc@marvell.com>
> Cc: netdev@vger.kernel.org; thomas.petazzoni@bootlin.com;
> davem@davemloft.net; Nadav Haklai <nadavh@marvell.com>; Yan Markman
> <ymarkman@marvell.com>; 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
> 
> ----------------------------------------------------------------------
> > +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");
> > +			return 0;
> > +		}
> > +		priv->cm3_base = devm_ioremap_resource(&pdev->dev,
> res);
> > +		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");
> > +			return 0;
> > +		}
> > +		priv->cm3_base = (void __iomem *)gen_pool_alloc(priv-
> >sram_pool,
> > +
> 	MSS_SRAM_SIZE);
> > +		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.