Message-ID: <m34pmo5g3d.fsf_-_@maximus.localdomain>
Date:	Tue, 08 May 2007 02:11:50 +0200
From:	Krzysztof Halasa <khc@...waw.pl>
To:	Michael-Luke Jones <mlj28@....ac.uk>
Cc:	Jeff Garzik <jeff@...zik.org>, netdev@...r.kernel.org,
	lkml <linux-kernel@...r.kernel.org>,
	Russell King <rmk@....linux.org.uk>,
	ARM Linux Mailing List 
	<linux-arm-kernel@...ts.arm.linux.org.uk>
Subject: [PATCH] Intel IXP4xx network drivers v.2

Adds a driver for IXP4xx built-in hardware queue manager.

Signed-off-by: Krzysztof Halasa <khc@...waw.pl>

diff --git a/arch/arm/mach-ixp4xx/Kconfig b/arch/arm/mach-ixp4xx/Kconfig
index 9715ef5..71ef55f 100644
--- a/arch/arm/mach-ixp4xx/Kconfig
+++ b/arch/arm/mach-ixp4xx/Kconfig
@@ -176,6 +176,12 @@ config IXP4XX_INDIRECT_PCI
 	  need to use the indirect method instead. If you don't know
 	  what you need, leave this option unselected.
 
+config IXP4XX_QMGR
+	tristate "IXP4xx Queue Manager support"
+	help
+	  This driver supports IXP4xx built-in hardware queue manager
+	  and is automatically selected by Ethernet and HSS drivers.
+
 endmenu
 
 endif
diff --git a/arch/arm/mach-ixp4xx/Makefile b/arch/arm/mach-ixp4xx/Makefile
index 3b87c47..f8e1afc 100644
--- a/arch/arm/mach-ixp4xx/Makefile
+++ b/arch/arm/mach-ixp4xx/Makefile
@@ -26,3 +26,4 @@ obj-$(CONFIG_MACH_NAS100D)	+= nas100d-setup.o nas100d-power.o
 obj-$(CONFIG_MACH_DSMG600)      += dsmg600-setup.o dsmg600-power.o
 
 obj-$(CONFIG_PCI)		+= $(obj-pci-$(CONFIG_PCI)) common-pci.o
+obj-$(CONFIG_IXP4XX_QMGR)	+= ixp4xx_qmgr.o
diff --git a/arch/arm/mach-ixp4xx/ixp4xx_qmgr.c b/arch/arm/mach-ixp4xx/ixp4xx_qmgr.c
new file mode 100644
index 0000000..b9e9bd6
--- /dev/null
+++ b/arch/arm/mach-ixp4xx/ixp4xx_qmgr.c
@@ -0,0 +1,273 @@
+/*
+ * Intel IXP4xx Queue Manager driver for Linux
+ *
+ * Copyright (C) 2007 Krzysztof Halasa <khc@...waw.pl>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2 of the GNU General Public License
+ * as published by the Free Software Foundation.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <asm/io.h>
+#include <asm/arch/qmgr.h>
+
+#define DEBUG		0
+
+struct qmgr_regs __iomem *qmgr_regs;
+static struct resource *mem_res;
+static spinlock_t qmgr_lock;
+static u32 used_sram_bitmap[4]; /* 128 16-dword pages */
+static void (*irq_handlers[HALF_QUEUES])(void *pdev);
+static void *irq_pdevs[HALF_QUEUES];
+
+void qmgr_set_irq(unsigned int queue, int src,
+		  void (*handler)(void *pdev), void *pdev)
+{
+	u32 __iomem *reg = &qmgr_regs->irqsrc[queue / 8]; /* 8 queues / u32 */
+	int bit = (queue % 8) * 4; /* 3 bits + 1 reserved bit per queue */
+	unsigned long flags;
+
+	src &= 7;
+	spin_lock_irqsave(&qmgr_lock, flags);
+	__raw_writel((__raw_readl(reg) & ~(7 << bit)) | (src << bit), reg);
+	irq_handlers[queue] = handler;
+	irq_pdevs[queue] = pdev;
+	spin_unlock_irqrestore(&qmgr_lock, flags);
+}
+
+
+static irqreturn_t qmgr_irq1(int irq, void *pdev)
+{
+	int i;
+	u32 val = __raw_readl(&qmgr_regs->irqstat[0]);
+	__raw_writel(val, &qmgr_regs->irqstat[0]); /* ACK */
+
+	for (i = 0; i < HALF_QUEUES; i++)
+		if (val & (1 << i))
+			irq_handlers[i](irq_pdevs[i]);
+
+	return val ? IRQ_HANDLED : 0;
+}
+
+
+void qmgr_enable_irq(unsigned int queue)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&qmgr_lock, flags);
+	__raw_writel(__raw_readl(&qmgr_regs->irqen[0]) | (1 << queue),
+		     &qmgr_regs->irqen[0]);
+	spin_unlock_irqrestore(&qmgr_lock, flags);
+}
+
+void qmgr_disable_irq(unsigned int queue)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&qmgr_lock, flags);
+	__raw_writel(__raw_readl(&qmgr_regs->irqen[0]) & ~(1 << queue),
+		     &qmgr_regs->irqen[0]);
+	spin_unlock_irqrestore(&qmgr_lock, flags);
+}
+
+static inline void shift_mask(u32 *mask)
+{
+	mask[3] = mask[3] << 1 | mask[2] >> 31;
+	mask[2] = mask[2] << 1 | mask[1] >> 31;
+	mask[1] = mask[1] << 1 | mask[0] >> 31;
+	mask[0] <<= 1;
+}
+
+int qmgr_request_queue(unsigned int queue, unsigned int len /* dwords */,
+		       unsigned int nearly_empty_watermark,
+		       unsigned int nearly_full_watermark)
+{
+	u32 cfg, addr = 0, mask[4]; /* in 16-dwords */
+	int err;
+
+	if (queue >= HALF_QUEUES)
+		return -ERANGE;
+
+	if ((nearly_empty_watermark | nearly_full_watermark) & ~7)
+		return -EINVAL;
+
+	switch (len) {
+	case  16:
+		cfg = 0 << 24;
+		mask[0] = 0x1;
+		break;
+	case  32:
+		cfg = 1 << 24;
+		mask[0] = 0x3;
+		break;
+	case  64:
+		cfg = 2 << 24;
+		mask[0] = 0xF;
+		break;
+	case 128:
+		cfg = 3 << 24;
+		mask[0] = 0xFF;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	cfg |= nearly_empty_watermark << 26;
+	cfg |= nearly_full_watermark << 29;
+	len /= 16;		/* in 16-dwords: 1, 2, 4 or 8 */
+	mask[1] = mask[2] = mask[3] = 0;
+
+	if (!try_module_get(THIS_MODULE))
+		return -ENODEV;
+
+	spin_lock_irq(&qmgr_lock);
+	if (__raw_readl(&qmgr_regs->sram[queue])) {
+		err = -EBUSY;
+		goto err;
+	}
+
+	while (1) {
+		if (!(used_sram_bitmap[0] & mask[0]) &&
+		    !(used_sram_bitmap[1] & mask[1]) &&
+		    !(used_sram_bitmap[2] & mask[2]) &&
+		    !(used_sram_bitmap[3] & mask[3]))
+			break; /* found free space */
+
+		addr++;
+		shift_mask(mask);
+		if (addr + len > ARRAY_SIZE(qmgr_regs->sram)) {
+			printk(KERN_ERR "qmgr: no free SRAM space for"
+			       " queue %i\n", queue);
+			err = -ENOMEM;
+			goto err;
+		}
+	}
+
+	used_sram_bitmap[0] |= mask[0];
+	used_sram_bitmap[1] |= mask[1];
+	used_sram_bitmap[2] |= mask[2];
+	used_sram_bitmap[3] |= mask[3];
+	__raw_writel(cfg | (addr << 14), &qmgr_regs->sram[queue]);
+	spin_unlock_irq(&qmgr_lock);
+
+#if DEBUG
+	printk(KERN_DEBUG "qmgr: requested queue %i, addr = 0x%02X\n",
+	       queue, addr);
+#endif
+	return 0;
+
+err:
+	spin_unlock_irq(&qmgr_lock);
+	module_put(THIS_MODULE);
+	return err;
+}
+
+void qmgr_release_queue(unsigned int queue)
+{
+	u32 cfg, addr, mask[4];
+
+	BUG_ON(queue >= HALF_QUEUES); /* not in valid range */
+
+	spin_lock_irq(&qmgr_lock);
+	cfg = __raw_readl(&qmgr_regs->sram[queue]);
+	addr = (cfg >> 14) & 0xFF;
+
+	BUG_ON(!addr);		/* not requested */
+
+	switch ((cfg >> 24) & 3) {
+	case 0: mask[0] = 0x1; break;
+	case 1: mask[0] = 0x3; break;
+	case 2: mask[0] = 0xF; break;
+	case 3: mask[0] = 0xFF; break;
+	}
+
+	while (addr--)
+		shift_mask(mask);
+
+	__raw_writel(0, &qmgr_regs->sram[queue]);
+
+	used_sram_bitmap[0] &= ~mask[0];
+	used_sram_bitmap[1] &= ~mask[1];
+	used_sram_bitmap[2] &= ~mask[2];
+	used_sram_bitmap[3] &= ~mask[3];
+	irq_handlers[queue] = NULL; /* catch IRQ bugs */
+	spin_unlock_irq(&qmgr_lock);
+
+	module_put(THIS_MODULE);
+#if DEBUG
+	printk(KERN_DEBUG "qmgr: released queue %i\n", queue);
+#endif
+}
+
+static int qmgr_init(void)
+{
+	int i, err;
+	mem_res = request_mem_region(IXP4XX_QMGR_BASE_PHYS,
+				     IXP4XX_QMGR_REGION_SIZE,
+				     "IXP4xx Queue Manager");
+	if (mem_res == NULL)
+		return -EBUSY;
+
+	qmgr_regs = ioremap(IXP4XX_QMGR_BASE_PHYS, IXP4XX_QMGR_REGION_SIZE);
+	if (qmgr_regs == NULL) {
+		err = -ENOMEM;
+		goto error_map;
+	}
+
+	/* reset qmgr registers */
+	for (i = 0; i < 4; i++) {
+		__raw_writel(0x33333333, &qmgr_regs->stat1[i]);
+		__raw_writel(0, &qmgr_regs->irqsrc[i]);
+	}
+	for (i = 0; i < 2; i++) {
+		__raw_writel(0, &qmgr_regs->stat2[i]);
+		__raw_writel(0xFFFFFFFF, &qmgr_regs->irqstat[i]); /* clear */
+		__raw_writel(0, &qmgr_regs->irqen[i]);
+	}
+
+	for (i = 0; i < QUEUES; i++)
+		__raw_writel(0, &qmgr_regs->sram[i]);
+
+	err = request_irq(IRQ_IXP4XX_QM1, qmgr_irq1, 0,
+			  "IXP4xx Queue Manager", NULL);
+	if (err) {
+		printk(KERN_ERR "qmgr: failed to request IRQ%i\n",
+		       IRQ_IXP4XX_QM1);
+		goto error_irq;
+	}
+
+	used_sram_bitmap[0] = 0xF; /* 4 first pages reserved for config */
+	spin_lock_init(&qmgr_lock);
+
+	printk(KERN_INFO "IXP4xx Queue Manager initialized.\n");
+	return 0;
+
+error_irq:
+	iounmap(qmgr_regs);
+error_map:
+	release_resource(mem_res);
+	return err;
+}
+
+static void qmgr_remove(void)
+{
+	free_irq(IRQ_IXP4XX_QM1, NULL);
+	synchronize_irq(IRQ_IXP4XX_QM1);
+	iounmap(qmgr_regs);
+	release_resource(mem_res);
+}
+
+module_init(qmgr_init);
+module_exit(qmgr_remove);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Krzysztof Halasa");
+
+EXPORT_SYMBOL(qmgr_regs);
+EXPORT_SYMBOL(qmgr_set_irq);
+EXPORT_SYMBOL(qmgr_enable_irq);
+EXPORT_SYMBOL(qmgr_disable_irq);
+EXPORT_SYMBOL(qmgr_request_queue);
+EXPORT_SYMBOL(qmgr_release_queue);
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