[ARM] 3052/1: add ixp2000 microcode loader

Patch from Lennert Buytenhek

This patch adds a microcode loader for the ixp2000 architecture.

The ixp2000 is an xscale-based CPU with a number of additional small
CPUs ('microengines') on die that can be programmed to do various
things.  Depending on the ixp2000 model, there are between 2 and 16
microengines.

This code provides an API that allows configuring the microengines,
loading code into them, and starting and stopping them and reading
out a number of status registers, and is used by the microengine
network driver that was recently announced to netdev.

Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Deepak Saxena <dsaxena@plexity.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 475 insertions, 1 deletions

diff --git a/arch/arm/mach-ixp2000/Makefile b/arch/arm/mach-ixp2000/Makefile
index 1e6139d42a92..9621aeb61f46 100644
--- a/arch/arm/mach-ixp2000/Makefile
+++ b/arch/arm/mach-ixp2000/Makefile
@@ -1,7 +1,7 @@
 #
 # Makefile for the linux kernel.
 #
-obj-y                   := core.o pci.o
+obj-y                   := core.o pci.o uengine.o
 obj-m                   :=
 obj-n                   :=
 obj-                    :=
diff --git a/arch/arm/mach-ixp2000/uengine.c b/arch/arm/mach-ixp2000/uengine.c
new file mode 100644
index 000000000000..43e234349d4a
--- /dev/null
+++ b/arch/arm/mach-ixp2000/uengine.c
@@ -0,0 +1,474 @@
+/*
+ * Generic library functions for the microengines found on the Intel
+ * IXP2000 series of network processors.
+ *
+ * Copyright (C) 2004, 2005 Lennert Buytenhek <buytenh@wantstofly.org>
+ * Dedicated to Marija Kulikova.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of the
+ * License, or (at your option) any later version.
+ */
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <asm/hardware.h>
+#include <asm/arch/ixp2000-regs.h>
+#include <asm/arch/uengine.h>
+#include <asm/io.h>
+
+#define USTORE_ADDRESS                  0x000
+#define USTORE_DATA_LOWER               0x004
+#define USTORE_DATA_UPPER               0x008
+#define CTX_ENABLES                     0x018
+#define CC_ENABLE                       0x01c
+#define CSR_CTX_POINTER                 0x020
+#define INDIRECT_CTX_STS                0x040
+#define ACTIVE_CTX_STS                  0x044
+#define INDIRECT_CTX_SIG_EVENTS         0x048
+#define INDIRECT_CTX_WAKEUP_EVENTS      0x050
+#define NN_PUT                          0x080
+#define NN_GET                          0x084
+#define TIMESTAMP_LOW                   0x0c0
+#define TIMESTAMP_HIGH                  0x0c4
+#define T_INDEX_BYTE_INDEX              0x0f4
+#define LOCAL_CSR_STATUS                0x180
+
+u32 ixp2000_uengine_mask;
+
+static void *ixp2000_uengine_csr_area(int uengine)
+{
+        return ((void *)IXP2000_UENGINE_CSR_VIRT_BASE) + (uengine << 10);
+}
+
+/*
+ * LOCAL_CSR_STATUS=1 after a read or write to a microengine's CSR
+ * space means that the microengine we tried to access was also trying
+ * to access its own CSR space on the same clock cycle as we did.  When
+ * this happens, we lose the arbitration process by default, and the
+ * read or write we tried to do was not actually performed, so we try
+ * again until it succeeds.
+ */
+u32 ixp2000_uengine_csr_read(int uengine, int offset)
+{
+        void *uebase;
+        u32 *local_csr_status;
+        u32 *reg;
+        u32 value;
+
+        uebase = ixp2000_uengine_csr_area(uengine);
+
+        local_csr_status = (u32 *)(uebase + LOCAL_CSR_STATUS);
+        reg = (u32 *)(uebase + offset);
+        do {
+                value = ixp2000_reg_read(reg);
+        } while (ixp2000_reg_read(local_csr_status) & 1);
+
+        return value;
+}
+EXPORT_SYMBOL(ixp2000_uengine_csr_read);
+
+void ixp2000_uengine_csr_write(int uengine, int offset, u32 value)
+{
+        void *uebase;
+        u32 *local_csr_status;
+        u32 *reg;
+
+        uebase = ixp2000_uengine_csr_area(uengine);
+
+        local_csr_status = (u32 *)(uebase + LOCAL_CSR_STATUS);
+        reg = (u32 *)(uebase + offset);
+        do {
+                ixp2000_reg_write(reg, value);
+        } while (ixp2000_reg_read(local_csr_status) & 1);
+}
+EXPORT_SYMBOL(ixp2000_uengine_csr_write);
+
+void ixp2000_uengine_reset(u32 uengine_mask)
+{
+        ixp2000_reg_write(IXP2000_RESET1, uengine_mask & ixp2000_uengine_mask);
+        ixp2000_reg_write(IXP2000_RESET1, 0);
+}
+EXPORT_SYMBOL(ixp2000_uengine_reset);
+
+void ixp2000_uengine_set_mode(int uengine, u32 mode)
+{
+        /*
+         * CTL_STR_PAR_EN: unconditionally enable parity checking on
+         * control store.
+         */
+        mode |= 0x10000000;
+        ixp2000_uengine_csr_write(uengine, CTX_ENABLES, mode);
+
+        /*
+         * Enable updating of condition codes.
+         */
+        ixp2000_uengine_csr_write(uengine, CC_ENABLE, 0x00002000);
+
+        /*
+         * Initialise other per-microengine registers.
+         */
+        ixp2000_uengine_csr_write(uengine, NN_PUT, 0x00);
+        ixp2000_uengine_csr_write(uengine, NN_GET, 0x00);
+        ixp2000_uengine_csr_write(uengine, T_INDEX_BYTE_INDEX, 0);
+}
+EXPORT_SYMBOL(ixp2000_uengine_set_mode);
+
+static int make_even_parity(u32 x)
+{
+        return hweight32(x) & 1;
+}
+
+static void ustore_write(int uengine, u64 insn)
+{
+        /*
+         * Generate even parity for top and bottom 20 bits.
+         */
+        insn |= (u64)make_even_parity((insn >> 20) & 0x000fffff) << 41;
+        insn |= (u64)make_even_parity(insn & 0x000fffff) << 40;
+
+        /*
+         * Write to microstore.  The second write auto-increments
+         * the USTORE_ADDRESS index register.
+         */
+        ixp2000_uengine_csr_write(uengine, USTORE_DATA_LOWER, (u32)insn);
+        ixp2000_uengine_csr_write(uengine, USTORE_DATA_UPPER, (u32)(insn >> 32));
+}
+
+void ixp2000_uengine_load_microcode(int uengine, u8 *ucode, int insns)
+{
+        int i;
+
+        /*
+         * Start writing to microstore at address 0.
+         */
+        ixp2000_uengine_csr_write(uengine, USTORE_ADDRESS, 0x80000000);
+        for (i = 0; i < insns; i++) {
+                u64 insn;
+
+                insn = (((u64)ucode[0]) << 32) |
+                        (((u64)ucode[1]) << 24) |
+                        (((u64)ucode[2]) << 16) |
+                        (((u64)ucode[3]) << 8) |
+                        ((u64)ucode[4]);
+                ucode += 5;
+
+                ustore_write(uengine, insn);
+        }
+
+        /*
+         * Pad with a few NOPs at the end (to avoid the microengine
+         * aborting as it prefetches beyond the last instruction), unless
+         * we run off the end of the instruction store first, at which
+         * point the address register will wrap back to zero.
+         */
+        for (i = 0; i < 4; i++) {
+                u32 addr;
+
+                addr = ixp2000_uengine_csr_read(uengine, USTORE_ADDRESS);
+                if (addr == 0x80000000)
+                        break;
+                ustore_write(uengine, 0xf0000c0300ULL);
+        }
+
+        /*
+         * End programming.
+         */
+        ixp2000_uengine_csr_write(uengine, USTORE_ADDRESS, 0x00000000);
+}
+EXPORT_SYMBOL(ixp2000_uengine_load_microcode);
+
+void ixp2000_uengine_init_context(int uengine, int context, int pc)
+{
+        /*
+         * Select the right context for indirect access.
+         */
+        ixp2000_uengine_csr_write(uengine, CSR_CTX_POINTER, context);
+
+        /*
+         * Initialise signal masks to immediately go to Ready state.
+         */
+        ixp2000_uengine_csr_write(uengine, INDIRECT_CTX_SIG_EVENTS, 1);
+        ixp2000_uengine_csr_write(uengine, INDIRECT_CTX_WAKEUP_EVENTS, 1);
+
+        /*
+         * Set program counter.
+         */
+        ixp2000_uengine_csr_write(uengine, INDIRECT_CTX_STS, pc);
+}
+EXPORT_SYMBOL(ixp2000_uengine_init_context);
+
+void ixp2000_uengine_start_contexts(int uengine, u8 ctx_mask)
+{
+        u32 mask;
+
+        /*
+         * Enable the specified context to go to Executing state.
+         */
+        mask = ixp2000_uengine_csr_read(uengine, CTX_ENABLES);
+        mask |= ctx_mask << 8;
+        ixp2000_uengine_csr_write(uengine, CTX_ENABLES, mask);
+}
+EXPORT_SYMBOL(ixp2000_uengine_start_contexts);
+
+void ixp2000_uengine_stop_contexts(int uengine, u8 ctx_mask)
+{
+        u32 mask;
+
+        /*
+         * Disable the Ready->Executing transition.  Note that this
+         * does not stop the context until it voluntarily yields.
+         */
+        mask = ixp2000_uengine_csr_read(uengine, CTX_ENABLES);
+        mask &= ~(ctx_mask << 8);
+        ixp2000_uengine_csr_write(uengine, CTX_ENABLES, mask);
+}
+EXPORT_SYMBOL(ixp2000_uengine_stop_contexts);
+
+static int check_ixp_type(struct ixp2000_uengine_code *c)
+{
+        u32 product_id;
+        u32 rev;
+
+        product_id = ixp2000_reg_read(IXP2000_PRODUCT_ID);
+        if (((product_id >> 16) & 0x1f) != 0)
+                return 0;
+
+        switch ((product_id >> 8) & 0xff) {
+        case 0:         /* IXP2800 */
+                if (!(c->cpu_model_bitmask & 4))
+                        return 0;
+                break;
+
+        case 1:         /* IXP2850 */
+                if (!(c->cpu_model_bitmask & 8))
+                        return 0;
+                break;
+
+        case 2:         /* IXP2400 */
+                if (!(c->cpu_model_bitmask & 2))
+                        return 0;
+                break;
+
+        default:
+                return 0;
+        }
+
+        rev = product_id & 0xff;
+        if (rev < c->cpu_min_revision || rev > c->cpu_max_revision)
+                return 0;
+
+        return 1;
+}
+
+static void generate_ucode(u8 *ucode, u32 *gpr_a, u32 *gpr_b)
+{
+        int offset;
+        int i;
+
+        offset = 0;
+
+        for (i = 0; i < 128; i++) {
+                u8 b3;
+                u8 b2;
+                u8 b1;
+                u8 b0;
+
+                b3 = (gpr_a[i] >> 24) & 0xff;
+                b2 = (gpr_a[i] >> 16) & 0xff;
+                b1 = (gpr_a[i] >> 8) & 0xff;
+                b0 = gpr_a[i] & 0xff;
+
+                // immed[@ai, (b1 << 8) | b0]
+                // 11110000 0000VVVV VVVV11VV VVVVVV00 1IIIIIII
+                ucode[offset++] = 0xf0;
+                ucode[offset++] = (b1 >> 4);
+                ucode[offset++] = (b1 << 4) | 0x0c | (b0 >> 6);
+                ucode[offset++] = (b0 << 2);
+                ucode[offset++] = 0x80 | i;
+
+                // immed_w1[@ai, (b3 << 8) | b2]
+                // 11110100 0100VVVV VVVV11VV VVVVVV00 1IIIIIII
+                ucode[offset++] = 0xf4;
+                ucode[offset++] = 0x40 | (b3 >> 4);
+                ucode[offset++] = (b3 << 4) | 0x0c | (b2 >> 6);
+                ucode[offset++] = (b2 << 2);
+                ucode[offset++] = 0x80 | i;
+        }
+
+        for (i = 0; i < 128; i++) {
+                u8 b3;
+                u8 b2;
+                u8 b1;
+                u8 b0;
+
+                b3 = (gpr_b[i] >> 24) & 0xff;
+                b2 = (gpr_b[i] >> 16) & 0xff;
+                b1 = (gpr_b[i] >> 8) & 0xff;
+                b0 = gpr_b[i] & 0xff;
+
+                // immed[@bi, (b1 << 8) | b0]
+                // 11110000 0000VVVV VVVV001I IIIIII11 VVVVVVVV
+                ucode[offset++] = 0xf0;
+                ucode[offset++] = (b1 >> 4);
+                ucode[offset++] = (b1 << 4) | 0x02 | (i >> 6);
+                ucode[offset++] = (i << 2) | 0x03;
+                ucode[offset++] = b0;
+
+                // immed_w1[@bi, (b3 << 8) | b2]
+                // 11110100 0100VVVV VVVV001I IIIIII11 VVVVVVVV
+                ucode[offset++] = 0xf4;
+                ucode[offset++] = 0x40 | (b3 >> 4);
+                ucode[offset++] = (b3 << 4) | 0x02 | (i >> 6);
+                ucode[offset++] = (i << 2) | 0x03;
+                ucode[offset++] = b2;
+        }
+
+        // ctx_arb[kill]
+        ucode[offset++] = 0xe0;
+        ucode[offset++] = 0x00;
+        ucode[offset++] = 0x01;
+        ucode[offset++] = 0x00;
+        ucode[offset++] = 0x00;
+}
+
+static int set_initial_registers(int uengine, struct ixp2000_uengine_code *c)
+{
+        int per_ctx_regs;
+        u32 *gpr_a;
+        u32 *gpr_b;
+        u8 *ucode;
+        int i;
+
+        gpr_a = kmalloc(128 * sizeof(u32), GFP_KERNEL);
+        gpr_b = kmalloc(128 * sizeof(u32), GFP_KERNEL);
+        ucode = kmalloc(513 * 5, GFP_KERNEL);
+        if (gpr_a == NULL || gpr_b == NULL || ucode == NULL) {
+                kfree(ucode);
+                kfree(gpr_b);
+                kfree(gpr_a);
+                return 1;
+        }
+
+        per_ctx_regs = 16;
+        if (c->uengine_parameters & IXP2000_UENGINE_4_CONTEXTS)
+                per_ctx_regs = 32;
+
+        memset(gpr_a, 0, sizeof(gpr_a));
+        memset(gpr_b, 0, sizeof(gpr_b));
+        for (i = 0; i < 256; i++) {
+                struct ixp2000_reg_value *r = c->initial_reg_values + i;
+                u32 *bank;
+                int inc;
+                int j;
+
+                if (r->reg == -1)
+                        break;
+
+                bank = (r->reg & 0x400) ? gpr_b : gpr_a;
+                inc = (r->reg & 0x80) ? 128 : per_ctx_regs;
+
+                j = r->reg & 0x7f;
+                while (j < 128) {
+                        bank[j] = r->value;
+                        j += inc;
+                }
+        }
+
+        generate_ucode(ucode, gpr_a, gpr_b);
+        ixp2000_uengine_load_microcode(uengine, ucode, 513);
+        ixp2000_uengine_init_context(uengine, 0, 0);
+        ixp2000_uengine_start_contexts(uengine, 0x01);
+        for (i = 0; i < 100; i++) {
+                u32 status;
+
+                status = ixp2000_uengine_csr_read(uengine, ACTIVE_CTX_STS);
+                if (!(status & 0x80000000))
+                        break;
+        }
+        ixp2000_uengine_stop_contexts(uengine, 0x01);
+
+        kfree(ucode);
+        kfree(gpr_b);
+        kfree(gpr_a);
+
+        return !!(i == 100);
+}
+
+int ixp2000_uengine_load(int uengine, struct ixp2000_uengine_code *c)
+{
+        int ctx;
+
+        if (!check_ixp_type(c))
+                return 1;
+
+        if (!(ixp2000_uengine_mask & (1 << uengine)))
+                return 1;
+
+        ixp2000_uengine_reset(1 << uengine);
+        ixp2000_uengine_set_mode(uengine, c->uengine_parameters);
+        if (set_initial_registers(uengine, c))
+                return 1;
+        ixp2000_uengine_load_microcode(uengine, c->insns, c->num_insns);
+
+        for (ctx = 0; ctx < 8; ctx++)
+                ixp2000_uengine_init_context(uengine, ctx, 0);
+
+        return 0;
+}
+EXPORT_SYMBOL(ixp2000_uengine_load);
+
+
+static int __init ixp2000_uengine_init(void)
+{
+        int uengine;
+        u32 value;
+
+        /*
+         * Determine number of microengines present.
+         */
+        switch ((ixp2000_reg_read(IXP2000_PRODUCT_ID) >> 8) & 0x1fff) {
+        case 0:         /* IXP2800 */
+        case 1:         /* IXP2850 */
+                ixp2000_uengine_mask = 0x00ff00ff;
+                break;
+
+        case 2:         /* IXP2400 */
+                ixp2000_uengine_mask = 0x000f000f;
+                break;
+
+        default:
+                printk(KERN_INFO "Detected unknown IXP2000 model (%.8x)\n",
+                        (unsigned int)ixp2000_reg_read(IXP2000_PRODUCT_ID));
+                ixp2000_uengine_mask = 0x00000000;
+                break;
+        }
+
+        /*
+         * Reset microengines.
+         */
+        ixp2000_reg_write(IXP2000_RESET1, ixp2000_uengine_mask);
+        ixp2000_reg_write(IXP2000_RESET1, 0);
+
+        /*
+         * Synchronise timestamp counters across all microengines.
+         */
+        value = ixp2000_reg_read(IXP2000_MISC_CONTROL);
+        ixp2000_reg_write(IXP2000_MISC_CONTROL, value & ~0x80);
+        for (uengine = 0; uengine < 32; uengine++) {
+                if (ixp2000_uengine_mask & (1 << uengine)) {
+                        ixp2000_uengine_csr_write(uengine, TIMESTAMP_LOW, 0);
+                        ixp2000_uengine_csr_write(uengine, TIMESTAMP_HIGH, 0);
+                }
+        }
+        ixp2000_reg_write(IXP2000_MISC_CONTROL, value | 0x80);
+
+        return 0;
+}
+
+subsys_initcall(ixp2000_uengine_init);