/* * PowerNV LPC bus handling. * * Copyright 2013 IBM Corp. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include #include #include #include #include #include #include #include #include #include #include #include #include static int opal_lpc_chip_id = -1; static u8 opal_lpc_inb(unsigned long port) { int64_t rc; __be32 data; if (opal_lpc_chip_id < 0 || port > 0xffff) return 0xff; rc = opal_lpc_read(opal_lpc_chip_id, OPAL_LPC_IO, port, &data, 1); return rc ? 0xff : be32_to_cpu(data); } static __le16 __opal_lpc_inw(unsigned long port) { int64_t rc; __be32 data; if (opal_lpc_chip_id < 0 || port > 0xfffe) return 0xffff; if (port & 1) return (__le16)opal_lpc_inb(port) << 8 | opal_lpc_inb(port + 1); rc = opal_lpc_read(opal_lpc_chip_id, OPAL_LPC_IO, port, &data, 2); return rc ? 0xffff : be32_to_cpu(data); } static u16 opal_lpc_inw(unsigned long port) { return le16_to_cpu(__opal_lpc_inw(port)); } static __le32 __opal_lpc_inl(unsigned long port) { int64_t rc; __be32 data; if (opal_lpc_chip_id < 0 || port > 0xfffc) return 0xffffffff; if (port & 3) return (__le32)opal_lpc_inb(port ) << 24 | (__le32)opal_lpc_inb(port + 1) << 16 | (__le32)opal_lpc_inb(port + 2) << 8 | opal_lpc_inb(port + 3); rc = opal_lpc_read(opal_lpc_chip_id, OPAL_LPC_IO, port, &data, 4); return rc ? 0xffffffff : be32_to_cpu(data); } static u32 opal_lpc_inl(unsigned long port) { return le32_to_cpu(__opal_lpc_inl(port)); } static void opal_lpc_outb(u8 val, unsigned long port) { if (opal_lpc_chip_id < 0 || port > 0xffff) return; opal_lpc_write(opal_lpc_chip_id, OPAL_LPC_IO, port, val, 1); } static void __opal_lpc_outw(__le16 val, unsigned long port) { if (opal_lpc_chip_id < 0 || port > 0xfffe) return; if (port & 1) { opal_lpc_outb(val >> 8, port); opal_lpc_outb(val , port + 1); return; } opal_lpc_write(opal_lpc_chip_id, OPAL_LPC_IO, port, val, 2); } static void opal_lpc_outw(u16 val, unsigned long port) { __opal_lpc_outw(cpu_to_le16(val), port); } static void __opal_lpc_outl(__le32 val, unsigned long port) { if (opal_lpc_chip_id < 0 || port > 0xfffc) return; if (port & 3) { opal_lpc_outb(val >> 24, port); opal_lpc_outb(val >> 16, port + 1); opal_lpc_outb(val >> 8, port + 2); opal_lpc_outb(val , port + 3); return; } opal_lpc_write(opal_lpc_chip_id, OPAL_LPC_IO, port, val, 4); } static void opal_lpc_outl(u32 val, unsigned long port) { __opal_lpc_outl(cpu_to_le32(val), port); } static void opal_lpc_insb(unsigned long p, void *b, unsigned long c) { u8 *ptr = b; while(c--) *(ptr++) = opal_lpc_inb(p); } static void opal_lpc_insw(unsigned long p, void *b, unsigned long c) { __le16 *ptr = b; while(c--) *(ptr++) = __opal_lpc_inw(p); } static void opal_lpc_insl(unsigned long p, void *b, unsigned long c) { __le32 *ptr = b; while(c--) *(ptr++) = __opal_lpc_inl(p); } static void opal_lpc_outsb(unsigned long p, const void *b, unsigned long c) { const u8 *ptr = b; while(c--) opal_lpc_outb(*(ptr++), p); } static void opal_lpc_outsw(unsigned long p, const void *b, unsigned long c) { const __le16 *ptr = b; while(c--) __opal_lpc_outw(*(ptr++), p); } static void opal_lpc_outsl(unsigned long p, const void *b, unsigned long c) { const __le32 *ptr = b; while(c--) __opal_lpc_outl(*(ptr++), p); } static const struct ppc_pci_io opal_lpc_io = { .inb = opal_lpc_inb, .inw = opal_lpc_inw, .inl = opal_lpc_inl, .outb = opal_lpc_outb, .outw = opal_lpc_outw, .outl = opal_lpc_outl, .insb = opal_lpc_insb, .insw = opal_lpc_insw, .insl = opal_lpc_insl, .outsb = opal_lpc_outsb, .outsw = opal_lpc_outsw, .outsl = opal_lpc_outsl, }; #ifdef CONFIG_DEBUG_FS struct lpc_debugfs_entry { enum OpalLPCAddressType lpc_type; }; static ssize_t lpc_debug_read(struct file *filp, char __user *ubuf, size_t count, loff_t *ppos) { struct lpc_debugfs_entry *lpc = filp->private_data; u32 data, pos, len, todo; int rc; if (!access_ok(VERIFY_WRITE, ubuf, count)) return -EFAULT; todo = count; while (todo) { pos = *ppos; /* * Select access size based on count and alignment and * access type. IO and MEM only support byte acceses, * FW supports all 3. */ len = 1; if (lpc->lpc_type == OPAL_LPC_FW) { if (todo > 3 && (pos & 3) == 0) len = 4; else if (todo > 1 && (pos & 1) == 0) len = 2; } rc = opal_lpc_read(opal_lpc_chip_id, lpc->lpc_type, pos, &data, len); if (rc) return -ENXIO; /* * Now there is some trickery with the data returned by OPAL * as it's the desired data right justified in a 32-bit BE * word. * * This is a very bad interface and I'm to blame for it :-( * * So we can't just apply a 32-bit swap to what comes from OPAL, * because user space expects the *bytes* to be in their proper * respective positions (ie, LPC position). * * So what we really want to do here is to shift data right * appropriately on a LE kernel. * * IE. If the LPC transaction has bytes B0, B1, B2 and B3 in that * order, we have in memory written to by OPAL at the "data" * pointer: * * Bytes: OPAL "data" LE "data" * 32-bit: B0 B1 B2 B3 B0B1B2B3 B3B2B1B0 * 16-bit: B0 B1 0000B0B1 B1B00000 * 8-bit: B0 000000B0 B0000000 * * So a BE kernel will have the leftmost of the above in the MSB * and rightmost in the LSB and can just then "cast" the u32 "data" * down to the appropriate quantity and write it. * * However, an LE kernel can't. It doesn't need to swap because a * load from data followed by a store to user are going to preserve * the byte ordering which is the wire byte order which is what the * user wants, but in order to "crop" to the right size, we need to * shift right first. */ switch(len) { case 4: rc = __put_user((u32)data, (u32 __user *)ubuf); break; case 2: #ifdef __LITTLE_ENDIAN__ data >>= 16; #endif rc = __put_user((u16)data, (u16 __user *)ubuf); break; default: #ifdef __LITTLE_ENDIAN__ data >>= 24; #endif rc = __put_user((u8)data, (u8 __user *)ubuf); break; } if (rc) return -EFAULT; *ppos += len; ubuf += len; todo -= len; } return count; } static ssize_t lpc_debug_write(struct file *filp, const char __user *ubuf, size_t count, loff_t *ppos) { struct lpc_debugfs_entry *lpc = filp->private_data; u32 data, pos, len, todo; int rc; if (!access_ok(VERIFY_READ, ubuf, count)) return -EFAULT; todo = count; while (todo) { pos = *ppos; /* * Select access size based on count and alignment and * access type. IO and MEM only support byte acceses, * FW supports all 3. */ len = 1; if (lpc->lpc_type == OPAL_LPC_FW) { if (todo > 3 && (pos & 3) == 0) len = 4; else if (todo > 1 && (pos & 1) == 0) len = 2; } /* * Similarly to the read case, we have some trickery here but * it's different to handle. We need to pass the value to OPAL in * a register whose layout depends on the access size. We want * to reproduce the memory layout of the user, however we aren't * doing a load from user and a store to another memory location * which would achieve that. Here we pass the value to OPAL via * a register which is expected to contain the "BE" interpretation * of the byte sequence. IE: for a 32-bit access, byte 0 should be * in the MSB. So here we *do* need to byteswap on LE. * * User bytes: LE "data" OPAL "data" * 32-bit: B0 B1 B2 B3 B3B2B1B0 B0B1B2B3 * 16-bit: B0 B1 0000B1B0 0000B0B1 * 8-bit: B0 000000B0 000000B0 */ switch(len) { case 4: rc = __get_user(data, (u32 __user *)ubuf); data = cpu_to_be32(data); break; case 2: rc = __get_user(data, (u16 __user *)ubuf); data = cpu_to_be16(data); break; default: rc = __get_user(data, (u8 __user *)ubuf); break; } if (rc) return -EFAULT; rc = opal_lpc_write(opal_lpc_chip_id, lpc->lpc_type, pos, data, len); if (rc) return -ENXIO; *ppos += len; ubuf += len; todo -= len; } return count; } static const struct file_operations lpc_fops = { .read = lpc_debug_read, .write = lpc_debug_write, .open = simple_open, .llseek = default_llseek, }; static int opal_lpc_debugfs_create_type(struct dentry *folder, const char *fname, enum OpalLPCAddressType type) { struct lpc_debugfs_entry *entry; entry = kzalloc(sizeof(*entry), GFP_KERNEL); if (!entry) return -ENOMEM; entry->lpc_type = type; debugfs_create_file(fname, 0600, folder, entry, &lpc_fops); return 0; } static int opal_lpc_init_debugfs(void) { struct dentry *root; int rc = 0; if (opal_lpc_chip_id < 0) return -ENODEV; root = debugfs_create_dir("lpc", powerpc_debugfs_root); rc |= opal_lpc_debugfs_create_type(root, "io", OPAL_LPC_IO); rc |= opal_lpc_debugfs_create_type(root, "mem", OPAL_LPC_MEM); rc |= opal_lpc_debugfs_create_type(root, "fw", OPAL_LPC_FW); return rc; } machine_device_initcall(powernv, opal_lpc_init_debugfs); #endif /* CONFIG_DEBUG_FS */ void opal_lpc_init(void) { struct device_node *np; /* * Look for a Power8 LPC bus tagged as "primary", * we currently support only one though the OPAL APIs * support any number. */ for_each_compatible_node(np, NULL, "ibm,power8-lpc") { if (!of_device_is_available(np)) continue; if (!of_get_property(np, "primary", NULL)) continue; opal_lpc_chip_id = of_get_ibm_chip_id(np); of_node_put(np); break; } if (opal_lpc_chip_id < 0) return; /* Setup special IO ops */ ppc_pci_io = opal_lpc_io; isa_io_special = true; pr_info("OPAL: Power8 LPC bus found, chip ID %d\n", opal_lpc_chip_id); }