Re: [PATCH v2 RFC net-next 03/18] net: mvpp2: add CM3 SRAM memory map
From: Andrew Lunn <andrew@lunn.ch>
Date: 2021-01-24 18:52:08
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On Sun, Jan 24, 2021 at 12:44:43PM +0000, Russell King - ARM Linux admin wrote:
On Sun, Jan 24, 2021 at 01:43:52PM +0200, stefanc@marvell.com wrote:quoted
+ priv->sram_pool = of_gen_pool_get(dn, "cm3-mem", 0); + if (!priv->sram_pool) { + if (!defer_once) { + defer_once = true; + /* Try defer once */ + return -EPROBE_DEFER; + } + dev_warn(&pdev->dev, "DT is too old, Flow control not supported\n"); + return -ENOMEM; + } + priv->cm3_base = (void __iomem *)gen_pool_alloc(priv->sram_pool, + MSS_SRAM_SIZE); + if (!priv->cm3_base) + return -ENOMEM;This probably could do with a comment indicating that it is reliant on this allocation happening at offset zero into the SRAM. The only reason that is guaranteed _at the moment_ is because the SRAM mapping is 0x800 bytes in size, and you are requesting 0x800 bytes in this allocation, so allocating the full size.
Hi Russell
I'm wondering if using a pool even makes sense. The ACPI case just
ioremap() the memory region. Either this memory is dedicated, and then
there is no need to use a pool, or the memory is shared, and at some
point the ACPI code is going to run into problems when some other
driver also wants access.
Andrew