On Tuesday 13 May 2014 12:10:39 Thomas Petazzoni wrote:
> +/*
> + * This ioremap hook is used on Armada 375/38x to ensure that PCIe
> + * memory areas are mapped as MT_MEMORY_RW_SO instead of
> + * MT_DEVICE. This is needed as a workaround for a deadlock issue
> + * between the PCIe interface and the cache controller.
> + */
> +static void __iomem *
> +armada_pcie_wa_ioremap_caller(phys_addr_t phys_addr, size_t size,
> + unsigned int mtype, void *caller)
> +{
> + struct resource pcie_mem;
> +
> + mvebu_mbus_get_pcie_mem_aperture(&pcie_mem);
> +
> + if (pcie_mem.start <= phys_addr && (phys_addr + size) <= pcie_mem.end)
> + mtype = MT_MEMORY_RW_SO;
> +
> + return __arm_ioremap_caller(phys_addr, size, mtype, caller);
> +}
Hmm, I think this needs some more explanation about which flags
you are actually interested in.
These are the three common mem types for ioremap:
#define PROT_PTE_DEVICE L_PTE_PRESENT|L_PTE_YOUNG|L_PTE_DIRTY|L_PTE_XN
#define PROT_SECT_DEVICE PMD_TYPE_SECT|PMD_SECT_AP_WRITE
[MT_DEVICE] = { /* Strongly ordered / ARMv6 shared device */
.prot_pte = PROT_PTE_DEVICE | L_PTE_MT_DEV_SHARED |
L_PTE_SHARED,
.prot_pte_s2 = s2_policy(PROT_PTE_S2_DEVICE) |
s2_policy(L_PTE_S2_MT_DEV_SHARED) |
L_PTE_SHARED,
.prot_sect = PROT_SECT_DEVICE | PMD_SECT_S,
.domain = DOMAIN_IO,
},
[MT_DEVICE_CACHED] = { /* ioremap_cached */
.prot_pte = PROT_PTE_DEVICE | L_PTE_MT_DEV_CACHED,
.prot_sect = PROT_SECT_DEVICE | PMD_SECT_WB,
.domain = DOMAIN_IO,
},
[MT_DEVICE_WC] = { /* ioremap_wc */
.prot_pte = PROT_PTE_DEVICE | L_PTE_MT_DEV_WC,
.prot_sect = PROT_SECT_DEVICE,
.domain = DOMAIN_IO,
},
and this is the one you enforce here:
[MT_MEMORY_RW_SO] = {
.prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
L_PTE_MT_UNCACHED | L_PTE_XN,
.prot_l1 = PMD_TYPE_TABLE,
.prot_sect = PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_SECT_S |
PMD_SECT_UNCACHED | PMD_SECT_XN,
.domain = DOMAIN_KERNEL,
},
So you set a different domain, and turn write-combined and cached mappings
into uncached mappings, and for uncached mappings you remove the "shared"
flag. Which of these changes is the one you actually need?
Arnd
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