--- /dev/null
+/*
+ * 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 <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/bug.h>
+#include <linux/debugfs.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+
+#include <asm/machdep.h>
+#include <asm/firmware.h>
+#include <asm/xics.h>
+#include <asm/opal.h>
+#include <asm/prom.h>
+#include <asm/uaccess.h>
+#include <asm/debug.h>
+
+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);
+ 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);
+}
Code Review / kvmfornfv.git / blobdiff