118 lines
2.7 KiB
C
118 lines
2.7 KiB
C
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.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/pgtable.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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