i.MX31: Image Processing Unit DMA and IRQ drivers

i.MX3x SoCs contain an Image Processing Unit, consisting of a Control
Module (CM), Display Interface (DI), Synchronous Display Controller (SDC),
Asynchronous Display Controller (ADC), Image Converter (IC), Post-Filter
(PF), Camera Sensor Interface (CSI), and an Image DMA Controller (IDMAC).
CM contains, among other blocks, an Interrupt Generator (IG) and a Clock
and Reset Control Unit (CRCU). This driver serves IDMAC and IG. They are
supported over dmaengine and irq-chip APIs respectively.

IDMAC is a specialised DMA controller, its DMA channels cannot be used for
general-purpose operations, even though it might be possible to configure
a memory-to-memory channel for memcpy operation. This driver will not work
with generic dmaengine clients, clients, wishing to use it must use
respective wrapper structures, they also must specify which channels they
require, as channels are hard-wired to specific IPU functions.

Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Guennadi Liakhovetski <lg@denx.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 413 insertions, 0 deletions

diff --git a/drivers/dma/ipu/ipu_irq.c b/drivers/dma/ipu/ipu_irq.c
new file mode 100644
index 000000000000..83f532cc767f
--- /dev/null
+++ b/drivers/dma/ipu/ipu_irq.c
@@ -0,0 +1,413 @@
+/*
+ * Copyright (C) 2008
+ * Guennadi Liakhovetski, DENX Software Engineering, <lg@denx.de>
+ *
+ * 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.
+ */
+
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/spinlock.h>
+#include <linux/delay.h>
+#include <linux/clk.h>
+#include <linux/irq.h>
+#include <linux/io.h>
+
+#include <mach/ipu.h>
+
+#include "ipu_intern.h"
+
+/*
+ * Register read / write - shall be inlined by the compiler
+ */
+static u32 ipu_read_reg(struct ipu *ipu, unsigned long reg)
+{
+        return __raw_readl(ipu->reg_ipu + reg);
+}
+
+static void ipu_write_reg(struct ipu *ipu, u32 value, unsigned long reg)
+{
+        __raw_writel(value, ipu->reg_ipu + reg);
+}
+
+
+/*
+ * IPU IRQ chip driver
+ */
+
+#define IPU_IRQ_NR_FN_BANKS 3
+#define IPU_IRQ_NR_ERR_BANKS 2
+#define IPU_IRQ_NR_BANKS (IPU_IRQ_NR_FN_BANKS + IPU_IRQ_NR_ERR_BANKS)
+
+struct ipu_irq_bank {
+        unsigned int    control;
+        unsigned int    status;
+        spinlock_t      lock;
+        struct ipu      *ipu;
+};
+
+static struct ipu_irq_bank irq_bank[IPU_IRQ_NR_BANKS] = {
+        /* 3 groups of functional interrupts */
+        {
+                .control        = IPU_INT_CTRL_1,
+                .status         = IPU_INT_STAT_1,
+        }, {
+                .control        = IPU_INT_CTRL_2,
+                .status         = IPU_INT_STAT_2,
+        }, {
+                .control        = IPU_INT_CTRL_3,
+                .status         = IPU_INT_STAT_3,
+        },
+        /* 2 groups of error interrupts */
+        {
+                .control        = IPU_INT_CTRL_4,
+                .status         = IPU_INT_STAT_4,
+        }, {
+                .control        = IPU_INT_CTRL_5,
+                .status         = IPU_INT_STAT_5,
+        },
+};
+
+struct ipu_irq_map {
+        unsigned int            irq;
+        int                     source;
+        struct ipu_irq_bank     *bank;
+        struct ipu              *ipu;
+};
+
+static struct ipu_irq_map irq_map[CONFIG_MX3_IPU_IRQS];
+/* Protects allocations from the above array of maps */
+static DEFINE_MUTEX(map_lock);
+/* Protects register accesses and individual mappings */
+static DEFINE_SPINLOCK(bank_lock);
+
+static struct ipu_irq_map *src2map(unsigned int src)
+{
+        int i;
+
+        for (i = 0; i < CONFIG_MX3_IPU_IRQS; i++)
+                if (irq_map[i].source == src)
+                        return irq_map + i;
+
+        return NULL;
+}
+
+static void ipu_irq_unmask(unsigned int irq)
+{
+        struct ipu_irq_map *map = get_irq_chip_data(irq);
+        struct ipu_irq_bank *bank;
+        uint32_t reg;
+        unsigned long lock_flags;
+
+        spin_lock_irqsave(&bank_lock, lock_flags);
+
+        bank = map->bank;
+        if (!bank) {
+                spin_unlock_irqrestore(&bank_lock, lock_flags);
+                pr_err("IPU: %s(%u) - unmapped!\n", __func__, irq);
+                return;
+        }
+
+        reg = ipu_read_reg(bank->ipu, bank->control);
+        reg |= (1UL << (map->source & 31));
+        ipu_write_reg(bank->ipu, reg, bank->control);
+
+        spin_unlock_irqrestore(&bank_lock, lock_flags);
+}
+
+static void ipu_irq_mask(unsigned int irq)
+{
+        struct ipu_irq_map *map = get_irq_chip_data(irq);
+        struct ipu_irq_bank *bank;
+        uint32_t reg;
+        unsigned long lock_flags;
+
+        spin_lock_irqsave(&bank_lock, lock_flags);
+
+        bank = map->bank;
+        if (!bank) {
+                spin_unlock_irqrestore(&bank_lock, lock_flags);
+                pr_err("IPU: %s(%u) - unmapped!\n", __func__, irq);
+                return;
+        }
+
+        reg = ipu_read_reg(bank->ipu, bank->control);
+        reg &= ~(1UL << (map->source & 31));
+        ipu_write_reg(bank->ipu, reg, bank->control);
+
+        spin_unlock_irqrestore(&bank_lock, lock_flags);
+}
+
+static void ipu_irq_ack(unsigned int irq)
+{
+        struct ipu_irq_map *map = get_irq_chip_data(irq);
+        struct ipu_irq_bank *bank;
+        unsigned long lock_flags;
+
+        spin_lock_irqsave(&bank_lock, lock_flags);
+
+        bank = map->bank;
+        if (!bank) {
+                spin_unlock_irqrestore(&bank_lock, lock_flags);
+                pr_err("IPU: %s(%u) - unmapped!\n", __func__, irq);
+                return;
+        }
+
+        ipu_write_reg(bank->ipu, 1UL << (map->source & 31), bank->status);
+        spin_unlock_irqrestore(&bank_lock, lock_flags);
+}
+
+/**
+ * ipu_irq_status() - returns the current interrupt status of the specified IRQ.
+ * @irq:        interrupt line to get status for.
+ * @return:     true if the interrupt is pending/asserted or false if the
+ *              interrupt is not pending.
+ */
+bool ipu_irq_status(unsigned int irq)
+{
+        struct ipu_irq_map *map = get_irq_chip_data(irq);
+        struct ipu_irq_bank *bank;
+        unsigned long lock_flags;
+        bool ret;
+
+        spin_lock_irqsave(&bank_lock, lock_flags);
+        bank = map->bank;
+        ret = bank && ipu_read_reg(bank->ipu, bank->status) &
+                (1UL << (map->source & 31));
+        spin_unlock_irqrestore(&bank_lock, lock_flags);
+
+        return ret;
+}
+
+/**
+ * ipu_irq_map() - map an IPU interrupt source to an IRQ number
+ * @source:     interrupt source bit position (see below)
+ * @return:     mapped IRQ number or negative error code
+ *
+ * The source parameter has to be explained further. On i.MX31 IPU has 137 IRQ
+ * sources, they are broken down in 5 32-bit registers, like 32, 32, 24, 32, 17.
+ * However, the source argument of this function is not the sequence number of
+ * the possible IRQ, but rather its bit position. So, first interrupt in fourth
+ * register has source number 96, and not 88. This makes calculations easier,
+ * and also provides forward compatibility with any future IPU implementations
+ * with any interrupt bit assignments.
+ */
+int ipu_irq_map(unsigned int source)
+{
+        int i, ret = -ENOMEM;
+        struct ipu_irq_map *map;
+
+        might_sleep();
+
+        mutex_lock(&map_lock);
+        map = src2map(source);
+        if (map) {
+                pr_err("IPU: Source %u already mapped to IRQ %u\n", source, map->irq);
+                ret = -EBUSY;
+                goto out;
+        }
+
+        for (i = 0; i < CONFIG_MX3_IPU_IRQS; i++) {
+                if (irq_map[i].source < 0) {
+                        unsigned long lock_flags;
+
+                        spin_lock_irqsave(&bank_lock, lock_flags);
+                        irq_map[i].source = source;
+                        irq_map[i].bank = irq_bank + source / 32;
+                        spin_unlock_irqrestore(&bank_lock, lock_flags);
+
+                        ret = irq_map[i].irq;
+                        pr_debug("IPU: mapped source %u to IRQ %u\n",
+                                 source, ret);
+                        break;
+                }
+        }
+out:
+        mutex_unlock(&map_lock);
+
+        if (ret < 0)
+                pr_err("IPU: couldn't map source %u: %d\n", source, ret);
+
+        return ret;
+}
+
+/**
+ * ipu_irq_map() - map an IPU interrupt source to an IRQ number
+ * @source:     interrupt source bit position (see ipu_irq_map())
+ * @return:     0 or negative error code
+ */
+int ipu_irq_unmap(unsigned int source)
+{
+        int i, ret = -EINVAL;
+
+        might_sleep();
+
+        mutex_lock(&map_lock);
+        for (i = 0; i < CONFIG_MX3_IPU_IRQS; i++) {
+                if (irq_map[i].source == source) {
+                        unsigned long lock_flags;
+
+                        pr_debug("IPU: unmapped source %u from IRQ %u\n",
+                                 source, irq_map[i].irq);
+
+                        spin_lock_irqsave(&bank_lock, lock_flags);
+                        irq_map[i].source = -EINVAL;
+                        irq_map[i].bank = NULL;
+                        spin_unlock_irqrestore(&bank_lock, lock_flags);
+
+                        ret = 0;
+                        break;
+                }
+        }
+        mutex_unlock(&map_lock);
+
+        return ret;
+}
+
+/* Chained IRQ handler for IPU error interrupt */
+static void ipu_irq_err(unsigned int irq, struct irq_desc *desc)
+{
+        struct ipu *ipu = get_irq_data(irq);
+        u32 status;
+        int i, line;
+
+        for (i = IPU_IRQ_NR_FN_BANKS; i < IPU_IRQ_NR_BANKS; i++) {
+                struct ipu_irq_bank *bank = irq_bank + i;
+
+                spin_lock(&bank_lock);
+                status = ipu_read_reg(ipu, bank->status);
+                /*
+                 * Don't think we have to clear all interrupts here, they will
+                 * be acked by ->handle_irq() (handle_level_irq). However, we
+                 * might want to clear unhandled interrupts after the loop...
+                 */
+                status &= ipu_read_reg(ipu, bank->control);
+                spin_unlock(&bank_lock);
+                while ((line = ffs(status))) {
+                        struct ipu_irq_map *map;
+
+                        line--;
+                        status &= ~(1UL << line);
+
+                        spin_lock(&bank_lock);
+                        map = src2map(32 * i + line);
+                        if (map)
+                                irq = map->irq;
+                        spin_unlock(&bank_lock);
+
+                        if (!map) {
+                                pr_err("IPU: Interrupt on unmapped source %u bank %d\n",
+                                       line, i);
+                                continue;
+                        }
+                        generic_handle_irq(irq);
+                }
+        }
+}
+
+/* Chained IRQ handler for IPU function interrupt */
+static void ipu_irq_fn(unsigned int irq, struct irq_desc *desc)
+{
+        struct ipu *ipu = get_irq_data(irq);
+        u32 status;
+        int i, line;
+
+        for (i = 0; i < IPU_IRQ_NR_FN_BANKS; i++) {
+                struct ipu_irq_bank *bank = irq_bank + i;
+
+                spin_lock(&bank_lock);
+                status = ipu_read_reg(ipu, bank->status);
+                /* Not clearing all interrupts, see above */
+                status &= ipu_read_reg(ipu, bank->control);
+                spin_unlock(&bank_lock);
+                while ((line = ffs(status))) {
+                        struct ipu_irq_map *map;
+
+                        line--;
+                        status &= ~(1UL << line);
+
+                        spin_lock(&bank_lock);
+                        map = src2map(32 * i + line);
+                        if (map)
+                                irq = map->irq;
+                        spin_unlock(&bank_lock);
+
+                        if (!map) {
+                                pr_err("IPU: Interrupt on unmapped source %u bank %d\n",
+                                       line, i);
+                                continue;
+                        }
+                        generic_handle_irq(irq);
+                }
+        }
+}
+
+static struct irq_chip ipu_irq_chip = {
+        .name   = "ipu_irq",
+        .ack    = ipu_irq_ack,
+        .mask   = ipu_irq_mask,
+        .unmask = ipu_irq_unmask,
+};
+
+/* Install the IRQ handler */
+int ipu_irq_attach_irq(struct ipu *ipu, struct platform_device *dev)
+{
+        struct ipu_platform_data *pdata = dev->dev.platform_data;
+        unsigned int irq, irq_base, i;
+
+        irq_base = pdata->irq_base;
+
+        for (i = 0; i < IPU_IRQ_NR_BANKS; i++)
+                irq_bank[i].ipu = ipu;
+
+        for (i = 0; i < CONFIG_MX3_IPU_IRQS; i++) {
+                int ret;
+
+                irq = irq_base + i;
+                ret = set_irq_chip(irq, &ipu_irq_chip);
+                if (ret < 0)
+                        return ret;
+                ret = set_irq_chip_data(irq, irq_map + i);
+                if (ret < 0)
+                        return ret;
+                irq_map[i].ipu = ipu;
+                irq_map[i].irq = irq;
+                irq_map[i].source = -EINVAL;
+                set_irq_handler(irq, handle_level_irq);
+#ifdef CONFIG_ARM
+                set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
+#endif
+        }
+
+        set_irq_data(ipu->irq_fn, ipu);
+        set_irq_chained_handler(ipu->irq_fn, ipu_irq_fn);
+
+        set_irq_data(ipu->irq_err, ipu);
+        set_irq_chained_handler(ipu->irq_err, ipu_irq_err);
+
+        return 0;
+}
+
+void ipu_irq_detach_irq(struct ipu *ipu, struct platform_device *dev)
+{
+        struct ipu_platform_data *pdata = dev->dev.platform_data;
+        unsigned int irq, irq_base;
+
+        irq_base = pdata->irq_base;
+
+        set_irq_chained_handler(ipu->irq_fn, NULL);
+        set_irq_data(ipu->irq_fn, NULL);
+
+        set_irq_chained_handler(ipu->irq_err, NULL);
+        set_irq_data(ipu->irq_err, NULL);
+
+        for (irq = irq_base; irq < irq_base + CONFIG_MX3_IPU_IRQS; irq++) {
+#ifdef CONFIG_ARM
+                set_irq_flags(irq, 0);
+#endif
+                set_irq_chip(irq, NULL);
+                set_irq_chip_data(irq, NULL);
+        }
+}