diff options
Diffstat (limited to 'arch/c6x/platforms/dscr.c')
| -rw-r--r-- | arch/c6x/platforms/dscr.c | 598 |
1 files changed, 598 insertions, 0 deletions
diff --git a/arch/c6x/platforms/dscr.c b/arch/c6x/platforms/dscr.c new file mode 100644 index 000000000000..f848a65ee646 --- /dev/null +++ b/arch/c6x/platforms/dscr.c @@ -0,0 +1,598 @@ +/* + * 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); +} |