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121 lines
2.8 KiB
121 lines
2.8 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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#include <linux/kernel.h> |
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#include <linux/export.h> |
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#include <linux/spinlock_types.h> |
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#include <linux/init.h> |
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#include <linux/pgtable.h> |
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#include <asm/page.h> |
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#include <asm/setup.h> |
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#include <asm/io.h> |
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#include <asm/cpufeature.h> |
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#include <asm/special_insns.h> |
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#include <asm/olpc_ofw.h> |
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/* address of OFW callback interface; will be NULL if OFW isn't found */ |
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static int (*olpc_ofw_cif)(int *); |
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/* page dir entry containing OFW's pgdir table; filled in by head_32.S */ |
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u32 olpc_ofw_pgd __initdata; |
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static DEFINE_SPINLOCK(ofw_lock); |
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#define MAXARGS 10 |
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void __init setup_olpc_ofw_pgd(void) |
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{ |
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pgd_t *base, *ofw_pde; |
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if (!olpc_ofw_cif) |
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return; |
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/* fetch OFW's PDE */ |
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base = early_ioremap(olpc_ofw_pgd, sizeof(olpc_ofw_pgd) * PTRS_PER_PGD); |
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if (!base) { |
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printk(KERN_ERR "failed to remap OFW's pgd - disabling OFW!\n"); |
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olpc_ofw_cif = NULL; |
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return; |
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} |
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ofw_pde = &base[OLPC_OFW_PDE_NR]; |
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/* install OFW's PDE permanently into the kernel's pgtable */ |
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set_pgd(&swapper_pg_dir[OLPC_OFW_PDE_NR], *ofw_pde); |
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/* implicit optimization barrier here due to uninline function return */ |
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early_iounmap(base, sizeof(olpc_ofw_pgd) * PTRS_PER_PGD); |
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} |
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int __olpc_ofw(const char *name, int nr_args, const void **args, int nr_res, |
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void **res) |
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{ |
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int ofw_args[MAXARGS + 3]; |
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unsigned long flags; |
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int ret, i, *p; |
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BUG_ON(nr_args + nr_res > MAXARGS); |
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if (!olpc_ofw_cif) |
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return -EIO; |
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ofw_args[0] = (int)name; |
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ofw_args[1] = nr_args; |
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ofw_args[2] = nr_res; |
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p = &ofw_args[3]; |
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for (i = 0; i < nr_args; i++, p++) |
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*p = (int)args[i]; |
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/* call into ofw */ |
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spin_lock_irqsave(&ofw_lock, flags); |
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ret = olpc_ofw_cif(ofw_args); |
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spin_unlock_irqrestore(&ofw_lock, flags); |
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if (!ret) { |
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for (i = 0; i < nr_res; i++, p++) |
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*((int *)res[i]) = *p; |
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} |
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return ret; |
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} |
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EXPORT_SYMBOL_GPL(__olpc_ofw); |
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bool olpc_ofw_present(void) |
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{ |
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return olpc_ofw_cif != NULL; |
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} |
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EXPORT_SYMBOL_GPL(olpc_ofw_present); |
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/* OFW cif _should_ be above this address */ |
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#define OFW_MIN 0xff000000 |
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/* OFW starts on a 1MB boundary */ |
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#define OFW_BOUND (1<<20) |
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void __init olpc_ofw_detect(void) |
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{ |
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struct olpc_ofw_header *hdr = &boot_params.olpc_ofw_header; |
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unsigned long start; |
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/* ensure OFW booted us by checking for "OFW " string */ |
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if (hdr->ofw_magic != OLPC_OFW_SIG) |
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return; |
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olpc_ofw_cif = (int (*)(int *))hdr->cif_handler; |
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if ((unsigned long)olpc_ofw_cif < OFW_MIN) { |
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printk(KERN_ERR "OFW detected, but cif has invalid address 0x%lx - disabling.\n", |
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(unsigned long)olpc_ofw_cif); |
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olpc_ofw_cif = NULL; |
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return; |
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} |
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/* determine where OFW starts in memory */ |
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start = round_down((unsigned long)olpc_ofw_cif, OFW_BOUND); |
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printk(KERN_INFO "OFW detected in memory, cif @ 0x%lx (reserving top %ldMB)\n", |
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(unsigned long)olpc_ofw_cif, (-start) >> 20); |
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reserve_top_address(-start); |
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} |
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bool __init olpc_ofw_is_installed(void) |
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{ |
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return olpc_ofw_cif != NULL; |
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}
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