Re: [PATCHv5 4/5] edac: altera: Add Altera L2 Cache and OCRAM EDAC Support

Mark Rutland
2014-12-02T15:25:25Z

Hi,

> +/* MPU L2 Register Defines */
> +#define ALTR_MPUL2_CONTROL_OFFSET 0x100
> +#define ALTR_MPUL2_CTL_CACHE_EN_MASK BIT(0)

These are just standard PL310 register definitions, no?

[...]

> +static void *ocram_alloc_mem(size_t size, void **other)
> +{
> + struct device_node *np;
> + struct gen_pool *gp;
> + void *sram_addr;
> +
> + np = of_find_compatible_node(NULL, NULL, "altr,ocram-edac");
> + if (!np)
> + return NULL;

Don't you need to have a corresponding of_node_put?

Is this ever called before the code above has probed? Can't you keep
this information around rather than probing it every time?

> +
> + gp = of_get_named_gen_pool(np, "iram", 0);
> + if (!gp)
> + return NULL;
> +
> + sram_addr = (void *)gen_pool_alloc(gp, size);
> + if (!sram_addr)
> + return NULL;
> +
> + memset(sram_addr, 0, size);

Is it safe to do a memset to the sram? How is it mapped?

[...]

> +static void *l2_alloc_mem(size_t size, void **other)
> +{
> + struct device *dev = *other;
> + void *ptemp = devm_kzalloc(dev, size, GFP_KERNEL);
> +
> + if (!ptemp)
> + return NULL;
> +
> + /* Make sure everything is written out */
> + wmb();
> + flush_cache_all();

Doesn't this just flush out _to_ the L2 (and not beyond)? Even then I
don't think that's safe with the MMU enabled.

Why is the flush necessary?

[...]

> +static int altr_l2_dependencies(struct platform_device *pdev,
> + void __iomem *base)
> +{
> + u32 control;
> + struct regmap *l2_vbase;
> +
> + control = readl(base) & ALTR_L2_ECC_EN_MASK;
> + if (!control) {
> + edac_printk(KERN_ERR, EDAC_DEVICE,
> + "L2: No ECC present, or ECC disabled\n");
> + return -ENODEV;
> + }
> +
> + l2_vbase = syscon_regmap_lookup_by_compatible("arm,pl310-cache");
> + if (IS_ERR(l2_vbase)) {
> + edac_printk(KERN_ERR, EDAC_DEVICE,
> + "L2:regmap for arm,pl310-cache lookup failed.\n");
> + return -ENODEV;
> + }

I must NAK any use of the L2 as a syscon device. It's simply not a
register file that was intended to be shared. I appreciate that you only
want to check something very simple, but we should use a higher level
API for that (and we should add one if we do not already have one)

> +
> + regmap_read(l2_vbase, ALTR_MPUL2_CONTROL_OFFSET, &control);
> + if (!(control & ALTR_MPUL2_CTL_CACHE_EN_MASK)) {
> + edac_printk(KERN_ERR, EDAC_DEVICE, "L2: Cache disabled\n");
> + return -ENODEV;
> + }
> +
> + return 0;
> +}
> +
> +const struct edac_device_prv_data l2ecc_data = {
> + .setup = altr_l2_dependencies,
> + .ce_clear_mask = 0,
> + .ue_clear_mask = 0,
> +#ifdef CONFIG_EDAC_DEBUG
> + .eccmgr_sysfs_attr = altr_l2_sysfs_attributes,
> + .alloc_mem = l2_alloc_mem,
> + .free_mem = l2_free_mem,
> + .ecc_enable_mask = ALTR_L2_ECC_EN_MASK,
> + .ce_set_mask = (ALTR_L2_ECC_EN_MASK | ALTR_L2_ECC_INJS_MASK),
> + .ue_set_mask = (ALTR_L2_ECC_EN_MASK | ALTR_L2_ECC_INJD_MASK),
> + .trig_alloc_sz = ALTR_TRIG_L2C_BYTE_SIZE,
> +#endif
> +};
> +
> +#endif /* #ifdef CONFIG_EDAC_ALTERA_L2C */
> +
> MODULE_LICENSE("GPL v2");
> MODULE_AUTHOR("Thor Thayer");
> -MODULE_DESCRIPTION("EDAC Driver for Altera SDRAM Controller");
> +MODULE_DESCRIPTION("EDAC Driver for Altera Memories");
> --
> 1.7.9.5
>
>