--- /dev/null
+/*
+ * Device State Control Registers driver
+ *
+ * Copyright (C) 2011 Texas Instruments Incorporated
+ * Author: Mark Salter <msalter@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+/*
+ * The Device State Control Registers (DSCR) provide SoC level control over
+ * a number of peripherals. Details vary considerably among the various SoC
+ * parts. In general, the DSCR block will provide one or more configuration
+ * registers often protected by a lock register. One or more key values must
+ * be written to a lock register in order to unlock the configuration register.
+ * The configuration register may be used to enable (and disable in some
+ * cases) SoC pin drivers, peripheral clock sources (internal or pin), etc.
+ * In some cases, a configuration register is write once or the individual
+ * bits are write once. That is, you may be able to enable a device, but
+ * will not be able to disable it.
+ *
+ * In addition to device configuration, the DSCR block may provide registers
+ * which are used to reset SoC peripherals, provide device ID information,
+ * provide MAC addresses, and other miscellaneous functions.
+ */
+
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+#include <asm/soc.h>
+#include <asm/dscr.h>
+
+#define MAX_DEVSTATE_IDS 32
+#define MAX_DEVCTL_REGS 8
+#define MAX_DEVSTAT_REGS 8
+#define MAX_LOCKED_REGS 4
+#define MAX_SOC_EMACS 2
+
+struct rmii_reset_reg {
+ u32 reg;
+ u32 mask;
+};
+
+/*
+ * Some registerd may be locked. In order to write to these
+ * registers, the key value must first be written to the lockreg.
+ */
+struct locked_reg {
+ u32 reg; /* offset from base */
+ u32 lockreg; /* offset from base */
+ u32 key; /* unlock key */
+};
+
+/*
+ * This describes a contiguous area of like control bits used to enable/disable
+ * SoC devices. Each controllable device is given an ID which is used by the
+ * individual device drivers to control the device state. These IDs start at
+ * zero and are assigned sequentially to the control bitfield ranges described
+ * by this structure.
+ */
+struct devstate_ctl_reg {
+ u32 reg; /* register holding the control bits */
+ u8 start_id; /* start id of this range */
+ u8 num_ids; /* number of devices in this range */
+ u8 enable_only; /* bits are write-once to enable only */
+ u8 enable; /* value used to enable device */
+ u8 disable; /* value used to disable device */
+ u8 shift; /* starting (rightmost) bit in range */
+ u8 nbits; /* number of bits per device */
+};
+
+
+/*
+ * This describes a region of status bits indicating the state of
+ * various devices. This is used internally to wait for status
+ * change completion when enabling/disabling a device. Status is
+ * optional and not all device controls will have a corresponding
+ * status.
+ */
+struct devstate_stat_reg {
+ u32 reg; /* register holding the status bits */
+ u8 start_id; /* start id of this range */
+ u8 num_ids; /* number of devices in this range */
+ u8 enable; /* value indicating enabled state */
+ u8 disable; /* value indicating disabled state */
+ u8 shift; /* starting (rightmost) bit in range */
+ u8 nbits; /* number of bits per device */
+};
+
+struct devstate_info {
+ struct devstate_ctl_reg *ctl;
+ struct devstate_stat_reg *stat;
+};
+
+/* These are callbacks to SOC-specific code. */
+struct dscr_ops {
+ void (*init)(struct device_node *node);
+};
+
+struct dscr_regs {
+ spinlock_t lock;
+ void __iomem *base;
+ u32 kick_reg[2];
+ u32 kick_key[2];
+ struct locked_reg locked[MAX_LOCKED_REGS];
+ struct devstate_info devstate_info[MAX_DEVSTATE_IDS];
+ struct rmii_reset_reg rmii_resets[MAX_SOC_EMACS];
+ struct devstate_ctl_reg devctl[MAX_DEVCTL_REGS];
+ struct devstate_stat_reg devstat[MAX_DEVSTAT_REGS];
+};
+
+static struct dscr_regs dscr;
+
+static struct locked_reg *find_locked_reg(u32 reg)
+{
+ int i;
+
+ for (i = 0; i < MAX_LOCKED_REGS; i++)
+ if (dscr.locked[i].key && reg == dscr.locked[i].reg)
+ return &dscr.locked[i];
+ return NULL;
+}
+
+/*
+ * Write to a register with one lock
+ */
+static void dscr_write_locked1(u32 reg, u32 val,
+ u32 lock, u32 key)
+{
+ void __iomem *reg_addr = dscr.base + reg;
+ void __iomem *lock_addr = dscr.base + lock;
+
+ /*
+ * For some registers, the lock is relocked after a short number
+ * of cycles. We have to put the lock write and register write in
+ * the same fetch packet to meet this timing. The .align ensures
+ * the two stw instructions are in the same fetch packet.
+ */
+ asm volatile ("b .s2 0f\n"
+ "nop 5\n"
+ " .align 5\n"
+ "0:\n"
+ "stw .D1T2 %3,*%2\n"
+ "stw .D1T2 %1,*%0\n"
+ :
+ : "a"(reg_addr), "b"(val), "a"(lock_addr), "b"(key)
+ );
+
+ /* in case the hw doesn't reset the lock */
+ soc_writel(0, lock_addr);
+}
+
+/*
+ * Write to a register protected by two lock registers
+ */
+static void dscr_write_locked2(u32 reg, u32 val,
+ u32 lock0, u32 key0,
+ u32 lock1, u32 key1)
+{
+ soc_writel(key0, dscr.base + lock0);
+ soc_writel(key1, dscr.base + lock1);
+ soc_writel(val, dscr.base + reg);
+ soc_writel(0, dscr.base + lock0);
+ soc_writel(0, dscr.base + lock1);
+}
+
+static void dscr_write(u32 reg, u32 val)
+{
+ struct locked_reg *lock;
+
+ lock = find_locked_reg(reg);
+ if (lock)
+ dscr_write_locked1(reg, val, lock->lockreg, lock->key);
+ else if (dscr.kick_key[0])
+ dscr_write_locked2(reg, val, dscr.kick_reg[0], dscr.kick_key[0],
+ dscr.kick_reg[1], dscr.kick_key[1]);
+ else
+ soc_writel(val, dscr.base + reg);
+}
+
+
+/*
+ * Drivers can use this interface to enable/disable SoC IP blocks.
+ */
+void dscr_set_devstate(int id, enum dscr_devstate_t state)
+{
+ struct devstate_ctl_reg *ctl;
+ struct devstate_stat_reg *stat;
+ struct devstate_info *info;
+ u32 ctl_val, val;
+ int ctl_shift, ctl_mask;
+ unsigned long flags;
+
+ if (!dscr.base)
+ return;
+
+ if (id < 0 || id >= MAX_DEVSTATE_IDS)
+ return;
+
+ info = &dscr.devstate_info[id];
+ ctl = info->ctl;
+ stat = info->stat;
+
+ if (ctl == NULL)
+ return;
+
+ ctl_shift = ctl->shift + ctl->nbits * (id - ctl->start_id);
+ ctl_mask = ((1 << ctl->nbits) - 1) << ctl_shift;
+
+ switch (state) {
+ case DSCR_DEVSTATE_ENABLED:
+ ctl_val = ctl->enable << ctl_shift;
+ break;
+ case DSCR_DEVSTATE_DISABLED:
+ if (ctl->enable_only)
+ return;
+ ctl_val = ctl->disable << ctl_shift;
+ break;
+ default:
+ return;
+ }
+
+ spin_lock_irqsave(&dscr.lock, flags);
+
+ val = soc_readl(dscr.base + ctl->reg);
+ val &= ~ctl_mask;
+ val |= ctl_val;
+
+ dscr_write(ctl->reg, val);
+
+ spin_unlock_irqrestore(&dscr.lock, flags);
+
+ if (!stat)
+ return;
+
+ ctl_shift = stat->shift + stat->nbits * (id - stat->start_id);
+
+ if (state == DSCR_DEVSTATE_ENABLED)
+ ctl_val = stat->enable;
+ else
+ ctl_val = stat->disable;
+
+ do {
+ val = soc_readl(dscr.base + stat->reg);
+ val >>= ctl_shift;
+ val &= ((1 << stat->nbits) - 1);
+ } while (val != ctl_val);
+}
+EXPORT_SYMBOL(dscr_set_devstate);
+
+/*
+ * Drivers can use this to reset RMII module.
+ */
+void dscr_rmii_reset(int id, int assert)
+{
+ struct rmii_reset_reg *r;
+ unsigned long flags;
+ u32 val;
+
+ if (id < 0 || id >= MAX_SOC_EMACS)
+ return;
+
+ r = &dscr.rmii_resets[id];
+ if (r->mask == 0)
+ return;
+
+ spin_lock_irqsave(&dscr.lock, flags);
+
+ val = soc_readl(dscr.base + r->reg);
+ if (assert)
+ dscr_write(r->reg, val | r->mask);
+ else
+ dscr_write(r->reg, val & ~(r->mask));
+
+ spin_unlock_irqrestore(&dscr.lock, flags);
+}
+EXPORT_SYMBOL(dscr_rmii_reset);
+
+static void __init dscr_parse_devstat(struct device_node *node,
+ void __iomem *base)
+{
+ u32 val;
+ int err;
+
+ err = of_property_read_u32_array(node, "ti,dscr-devstat", &val, 1);
+ if (!err)
+ c6x_devstat = soc_readl(base + val);
+ printk(KERN_INFO "DEVSTAT: %08x\n", c6x_devstat);
+}
+
+static void __init dscr_parse_silicon_rev(struct device_node *node,
+ void __iomem *base)
+{
+ u32 vals[3];
+ int err;
+
+ err = of_property_read_u32_array(node, "ti,dscr-silicon-rev", vals, 3);
+ if (!err) {
+ c6x_silicon_rev = soc_readl(base + vals[0]);
+ c6x_silicon_rev >>= vals[1];
+ c6x_silicon_rev &= vals[2];
+ }
+}
+
+/*
+ * Some SoCs will have a pair of fuse registers which hold
+ * an ethernet MAC address. The "ti,dscr-mac-fuse-regs"
+ * property is a mapping from fuse register bytes to MAC
+ * address bytes. The expected format is:
+ *
+ * ti,dscr-mac-fuse-regs = <reg0 b3 b2 b1 b0
+ * reg1 b3 b2 b1 b0>
+ *
+ * reg0 and reg1 are the offsets of the two fuse registers.
+ * b3-b0 positionally represent bytes within the fuse register.
+ * b3 is the most significant byte and b0 is the least.
+ * Allowable values for b3-b0 are:
+ *
+ * 0 = fuse register byte not used in MAC address
+ * 1-6 = index+1 into c6x_fuse_mac[]
+ */
+static void __init dscr_parse_mac_fuse(struct device_node *node,
+ void __iomem *base)
+{
+ u32 vals[10], fuse;
+ int f, i, j, err;
+
+ err = of_property_read_u32_array(node, "ti,dscr-mac-fuse-regs",
+ vals, 10);
+ if (err)
+ return;
+
+ for (f = 0; f < 2; f++) {
+ fuse = soc_readl(base + vals[f * 5]);
+ for (j = (f * 5) + 1, i = 24; i >= 0; i -= 8, j++)
+ if (vals[j] && vals[j] <= 6)
+ c6x_fuse_mac[vals[j] - 1] = fuse >> i;
+ }
+}
+
+static void __init dscr_parse_rmii_resets(struct device_node *node,
+ void __iomem *base)
+{
+ const __be32 *p;
+ int i, size;
+
+ /* look for RMII reset registers */
+ p = of_get_property(node, "ti,dscr-rmii-resets", &size);
+ if (p) {
+ /* parse all the reg/mask pairs we can handle */
+ size /= (sizeof(*p) * 2);
+ if (size > MAX_SOC_EMACS)
+ size = MAX_SOC_EMACS;
+
+ for (i = 0; i < size; i++) {
+ dscr.rmii_resets[i].reg = be32_to_cpup(p++);
+ dscr.rmii_resets[i].mask = be32_to_cpup(p++);
+ }
+ }
+}
+
+
+static void __init dscr_parse_privperm(struct device_node *node,
+ void __iomem *base)
+{
+ u32 vals[2];
+ int err;
+
+ err = of_property_read_u32_array(node, "ti,dscr-privperm", vals, 2);
+ if (err)
+ return;
+ dscr_write(vals[0], vals[1]);
+}
+
+/*
+ * SoCs may have "locked" DSCR registers which can only be written
+ * to only after writing a key value to a lock registers. These
+ * regisers can be described with the "ti,dscr-locked-regs" property.
+ * This property provides a list of register descriptions with each
+ * description consisting of three values.
+ *
+ * ti,dscr-locked-regs = <reg0 lockreg0 key0
+ * ...
+ * regN lockregN keyN>;
+ *
+ * reg is the offset of the locked register
+ * lockreg is the offset of the lock register
+ * key is the unlock key written to lockreg
+ *
+ */
+static void __init dscr_parse_locked_regs(struct device_node *node,
+ void __iomem *base)
+{
+ struct locked_reg *r;
+ const __be32 *p;
+ int i, size;
+
+ p = of_get_property(node, "ti,dscr-locked-regs", &size);
+ if (p) {
+ /* parse all the register descriptions we can handle */
+ size /= (sizeof(*p) * 3);
+ if (size > MAX_LOCKED_REGS)
+ size = MAX_LOCKED_REGS;
+
+ for (i = 0; i < size; i++) {
+ r = &dscr.locked[i];
+
+ r->reg = be32_to_cpup(p++);
+ r->lockreg = be32_to_cpup(p++);
+ r->key = be32_to_cpup(p++);
+ }
+ }
+}
+
+/*
+ * SoCs may have DSCR registers which are only write enabled after
+ * writing specific key values to two registers. The two key registers
+ * and the key values can be parsed from a "ti,dscr-kick-regs"
+ * propety with the following layout:
+ *
+ * ti,dscr-kick-regs = <kickreg0 key0 kickreg1 key1>
+ *
+ * kickreg is the offset of the "kick" register
+ * key is the value which unlocks writing for protected regs
+ */
+static void __init dscr_parse_kick_regs(struct device_node *node,
+ void __iomem *base)
+{
+ u32 vals[4];
+ int err;
+
+ err = of_property_read_u32_array(node, "ti,dscr-kick-regs", vals, 4);
+ if (!err) {
+ dscr.kick_reg[0] = vals[0];
+ dscr.kick_key[0] = vals[1];
+ dscr.kick_reg[1] = vals[2];
+ dscr.kick_key[1] = vals[3];
+ }
+}
+
+
+/*
+ * SoCs may provide controls to enable/disable individual IP blocks. These
+ * controls in the DSCR usually control pin drivers but also may control
+ * clocking and or resets. The device tree is used to describe the bitfields
+ * in registers used to control device state. The number of bits and their
+ * values may vary even within the same register.
+ *
+ * The layout of these bitfields is described by the ti,dscr-devstate-ctl-regs
+ * property. This property is a list where each element describes a contiguous
+ * range of control fields with like properties. Each element of the list
+ * consists of 7 cells with the following values:
+ *
+ * start_id num_ids reg enable disable start_bit nbits
+ *
+ * start_id is device id for the first device control in the range
+ * num_ids is the number of device controls in the range
+ * reg is the offset of the register holding the control bits
+ * enable is the value to enable a device
+ * disable is the value to disable a device (0xffffffff if cannot disable)
+ * start_bit is the bit number of the first bit in the range
+ * nbits is the number of bits per device control
+ */
+static void __init dscr_parse_devstate_ctl_regs(struct device_node *node,
+ void __iomem *base)
+{
+ struct devstate_ctl_reg *r;
+ const __be32 *p;
+ int i, j, size;
+
+ p = of_get_property(node, "ti,dscr-devstate-ctl-regs", &size);
+ if (p) {
+ /* parse all the ranges we can handle */
+ size /= (sizeof(*p) * 7);
+ if (size > MAX_DEVCTL_REGS)
+ size = MAX_DEVCTL_REGS;
+
+ for (i = 0; i < size; i++) {
+ r = &dscr.devctl[i];
+
+ r->start_id = be32_to_cpup(p++);
+ r->num_ids = be32_to_cpup(p++);
+ r->reg = be32_to_cpup(p++);
+ r->enable = be32_to_cpup(p++);
+ r->disable = be32_to_cpup(p++);
+ if (r->disable == 0xffffffff)
+ r->enable_only = 1;
+ r->shift = be32_to_cpup(p++);
+ r->nbits = be32_to_cpup(p++);
+
+ for (j = r->start_id;
+ j < (r->start_id + r->num_ids);
+ j++)
+ dscr.devstate_info[j].ctl = r;
+ }
+ }
+}
+
+/*
+ * SoCs may provide status registers indicating the state (enabled/disabled) of
+ * devices on the SoC. The device tree is used to describe the bitfields in
+ * registers used to provide device status. The number of bits and their
+ * values used to provide status may vary even within the same register.
+ *
+ * The layout of these bitfields is described by the ti,dscr-devstate-stat-regs
+ * property. This property is a list where each element describes a contiguous
+ * range of status fields with like properties. Each element of the list
+ * consists of 7 cells with the following values:
+ *
+ * start_id num_ids reg enable disable start_bit nbits
+ *
+ * start_id is device id for the first device status in the range
+ * num_ids is the number of devices covered by the range
+ * reg is the offset of the register holding the status bits
+ * enable is the value indicating device is enabled
+ * disable is the value indicating device is disabled
+ * start_bit is the bit number of the first bit in the range
+ * nbits is the number of bits per device status
+ */
+static void __init dscr_parse_devstate_stat_regs(struct device_node *node,
+ void __iomem *base)
+{
+ struct devstate_stat_reg *r;
+ const __be32 *p;
+ int i, j, size;
+
+ p = of_get_property(node, "ti,dscr-devstate-stat-regs", &size);
+ if (p) {
+ /* parse all the ranges we can handle */
+ size /= (sizeof(*p) * 7);
+ if (size > MAX_DEVSTAT_REGS)
+ size = MAX_DEVSTAT_REGS;
+
+ for (i = 0; i < size; i++) {
+ r = &dscr.devstat[i];
+
+ r->start_id = be32_to_cpup(p++);
+ r->num_ids = be32_to_cpup(p++);
+ r->reg = be32_to_cpup(p++);
+ r->enable = be32_to_cpup(p++);
+ r->disable = be32_to_cpup(p++);
+ r->shift = be32_to_cpup(p++);
+ r->nbits = be32_to_cpup(p++);
+
+ for (j = r->start_id;
+ j < (r->start_id + r->num_ids);
+ j++)
+ dscr.devstate_info[j].stat = r;
+ }
+ }
+}
+
+static struct of_device_id dscr_ids[] __initdata = {
+ { .compatible = "ti,c64x+dscr" },
+ {}
+};
+
+/*
+ * Probe for DSCR area.
+ *
+ * This has to be done early on in case timer or interrupt controller
+ * needs something. e.g. On C6455 SoC, timer must be enabled through
+ * DSCR before it is functional.
+ */
+void __init dscr_probe(void)
+{
+ struct device_node *node;
+ void __iomem *base;
+
+ spin_lock_init(&dscr.lock);
+
+ node = of_find_matching_node(NULL, dscr_ids);
+ if (!node)
+ return;
+
+ base = of_iomap(node, 0);
+ if (!base) {
+ of_node_put(node);
+ return;
+ }
+
+ dscr.base = base;
+
+ dscr_parse_devstat(node, base);
+ dscr_parse_silicon_rev(node, base);
+ dscr_parse_mac_fuse(node, base);
+ dscr_parse_rmii_resets(node, base);
+ dscr_parse_locked_regs(node, base);
+ dscr_parse_kick_regs(node, base);
+ dscr_parse_devstate_ctl_regs(node, base);
+ dscr_parse_devstate_stat_regs(node, base);
+ dscr_parse_privperm(node, base);
+}
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