[PATCH v3] powerpc/5200: add LocalPlus bus FIFO device driver
Grant Likely
grant.likely at secretlab.ca
Thu Jun 18 12:39:58 EST 2009
From: Grant Likely <grant.likely at secretlab.ca>
This is a driver for the LocalPlus bus FIFO device
Signed-off-by: Grant Likely <grant.likely at secretlab.ca>
---
arch/powerpc/include/asm/mpc52xx.h | 36 ++
arch/powerpc/platforms/52xx/Kconfig | 4
arch/powerpc/platforms/52xx/Makefile | 1
arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c | 458 +++++++++++++++++++++++++
4 files changed, 499 insertions(+), 0 deletions(-)
create mode 100644 arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c
diff --git a/arch/powerpc/include/asm/mpc52xx.h b/arch/powerpc/include/asm/mpc52xx.h
index 6716850..974fc8f 100644
--- a/arch/powerpc/include/asm/mpc52xx.h
+++ b/arch/powerpc/include/asm/mpc52xx.h
@@ -283,6 +283,42 @@ extern int mpc52xx_gpt_start_timer(struct mpc52xx_gpt_priv *gpt, int period,
int continuous);
extern void mpc52xx_gpt_stop_timer(struct mpc52xx_gpt_priv *gpt);
+/* mpc52xx_lpbfifo.c */
+#define MPC52XX_LPBFIFO_FLAG_READ (0)
+#define MPC52XX_LPBFIFO_FLAG_WRITE (1<<0)
+#define MPC52XX_LPBFIFO_FLAG_NO_INCREMENT (1<<1)
+#define MPC52XX_LPBFIFO_FLAG_NO_DMA (1<<2)
+#define MPC52XX_LPBFIFO_FLAG_POLL_DMA (1<<3)
+
+struct mpc52xx_lpbfifo_request {
+ struct list_head list;
+
+ /* localplus bus address */
+ unsigned int cs;
+ size_t offset;
+
+ /* Memory address */
+ void *data;
+ phys_addr_t data_phys;
+
+ /* Details of transfer */
+ size_t size;
+ size_t pos; /* current position of transfer */
+ int flags;
+
+ /* What to do when finished */
+ void (*callback)(struct mpc52xx_lpbfifo_request *);
+
+ void *priv; /* Driver private data */
+
+ /* statistics */
+ int irq_count;
+ int irq_ticks;
+};
+
+extern int mpc52xx_lpbfifo_submit(struct mpc52xx_lpbfifo_request *req);
+extern void mpc52xx_lpbfifo_abort(struct mpc52xx_lpbfifo_request *req);
+
/* mpc52xx_pic.c */
extern void mpc52xx_init_irq(void);
extern unsigned int mpc52xx_get_irq(void);
diff --git a/arch/powerpc/platforms/52xx/Kconfig b/arch/powerpc/platforms/52xx/Kconfig
index 8b8e956..d64783e 100644
--- a/arch/powerpc/platforms/52xx/Kconfig
+++ b/arch/powerpc/platforms/52xx/Kconfig
@@ -62,3 +62,7 @@ config PPC_MPC5200_GPIO
select GENERIC_GPIO
help
Enable gpiolib support for mpc5200 based boards
+
+config PPC_MPC5200_LPBFIFO
+ tristate "MPC5200 LocalPlus bus FIFO driver"
+ depends on PPC_MPC52xx
diff --git a/arch/powerpc/platforms/52xx/Makefile b/arch/powerpc/platforms/52xx/Makefile
index bfd4f52..2bc8cd0 100644
--- a/arch/powerpc/platforms/52xx/Makefile
+++ b/arch/powerpc/platforms/52xx/Makefile
@@ -15,3 +15,4 @@ ifeq ($(CONFIG_PPC_LITE5200),y)
endif
obj-$(CONFIG_PPC_MPC5200_GPIO) += mpc52xx_gpio.o
+obj-$(CONFIG_PPC_MPC5200_LPBFIFO) += mpc52xx_lpbfifo.o
diff --git a/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c b/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c
new file mode 100644
index 0000000..fe32ae5
--- /dev/null
+++ b/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c
@@ -0,0 +1,458 @@
+/*
+ * LocalPlus Bus FIFO driver for the Freescale MPC52xx.
+ *
+ * Copyright (C) 2009 Secret Lab Technologies Ltd.
+ *
+ * This file is released under the GPLv2
+ *
+ * Todo:
+ * - Add support for multiple requests to be queued.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/spinlock.h>
+#include <asm/io.h>
+#include <asm/prom.h>
+#include <asm/mpc52xx.h>
+#include <asm/time.h>
+
+#include <sysdev/bestcomm/bestcomm.h>
+#include <sysdev/bestcomm/bestcomm_priv.h>
+#include <sysdev/bestcomm/gen_bd.h>
+
+MODULE_AUTHOR("Grant Likely <grant.likely at secretlab.ca>");
+MODULE_DESCRIPTION("MPC5200 LocalPlus FIFO device driver");
+MODULE_LICENSE("GPL");
+
+#define LPBFIFO_REG_PACKET_SIZE (0x00)
+#define LPBFIFO_REG_START_ADDRESS (0x04)
+#define LPBFIFO_REG_CONTROL (0x08)
+#define LPBFIFO_REG_ENABLE (0x0C)
+#define LPBFIFO_REG_BYTES_DONE_STATUS (0x14)
+#define LPBFIFO_REG_FIFO_DATA (0x40)
+#define LPBFIFO_REG_FIFO_STATUS (0x44)
+#define LPBFIFO_REG_FIFO_CONTROL (0x48)
+#define LPBFIFO_REG_FIFO_ALARM (0x4C)
+
+struct mpc52xx_lpbfifo {
+ struct device *dev;
+ phys_addr_t regs_phys;
+ void __iomem *regs;
+ int irq;
+ spinlock_t lock;
+
+ struct bcom_task *bcom_tx_task;
+ struct bcom_task *bcom_rx_task;
+ struct bcom_task *bcom_cur_task;
+
+ /* Current state data */
+ struct mpc52xx_lpbfifo_request *req;
+};
+
+/* The MPC5200 has only one fifo, so only need one instance structure */
+static struct mpc52xx_lpbfifo lpbfifo;
+
+/**
+ * mpc52xx_lpbfifo_kick - Trigger the next block of data to be transfered
+ */
+static void mpc52xx_lpbfifo_kick(struct mpc52xx_lpbfifo_request *req)
+{
+ size_t transfer_size = req->size - req->pos;
+ struct bcom_bd *bd;
+ void __iomem *reg;
+ u32 *data;
+ int i;
+
+ /* Set and clear the reset bits; is good practice in User Manual */
+ out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x01010000);
+
+ if (req->flags & MPC52XX_LPBFIFO_FLAG_NO_DMA) {
+ /* While the FIFO can be setup for transfer sizes as large as
+ * 16M-1, the FIFO itself is only 512 bytes deep and it does
+ * not generate interrupts for FIFO full events (only transfer
+ * complete will raise an IRQ). Therefore when not using
+ * Bestcomm to drive the FIFO it needs to either be polled, or
+ * transfers need to constrained to the size of the fifo.
+ *
+ * This driver restricts the size of the transfer
+ */
+ if (transfer_size > 512)
+ transfer_size = 512;
+
+ /* Load the FIFO with data */
+ if (req->flags & MPC52XX_LPBFIFO_FLAG_WRITE) {
+ reg = lpbfifo.regs + LPBFIFO_REG_FIFO_DATA;
+ data = req->data + req->pos;
+ for (i = 0; i < transfer_size; i += 4)
+ out_be32(reg, *data++);
+ }
+
+ /* Unmask both error and completion irqs */
+ out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x00000301);
+ } else {
+ /* Choose the correct direction */
+ if (req->flags & MPC52XX_LPBFIFO_FLAG_WRITE)
+ lpbfifo.bcom_cur_task = lpbfifo.bcom_tx_task;
+ else
+ lpbfifo.bcom_cur_task = lpbfifo.bcom_rx_task;
+
+ bd = bcom_prepare_next_buffer(lpbfifo.bcom_cur_task);
+ bd->status = transfer_size;
+ transfer_size += 4; /* BLECH! */
+ bd->data[0] = req->data_phys + req->pos;
+ bcom_submit_next_buffer(lpbfifo.bcom_cur_task, NULL);
+
+ /* Unmask error irq */
+ out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x00000201);
+ }
+
+ /* Set transfer size, width, chip select and READ mode */
+ out_be32(lpbfifo.regs + LPBFIFO_REG_START_ADDRESS,
+ req->offset + req->pos);
+ out_be32(lpbfifo.regs + LPBFIFO_REG_PACKET_SIZE, transfer_size);
+ out_be32(lpbfifo.regs + LPBFIFO_REG_CONTROL, req->cs << 24 | 0x010008);
+
+ /* Kick it off */
+ out_8(lpbfifo.regs + LPBFIFO_REG_PACKET_SIZE, 0x01);
+ if (!(req->flags & MPC52XX_LPBFIFO_FLAG_NO_DMA))
+ bcom_enable(lpbfifo.bcom_cur_task);
+}
+
+/**
+ * mpc52xx_lpbfifo_irq - IRQ handler for LPB FIFO
+ */
+static irqreturn_t mpc52xx_lpbfifo_irq(int irq, void *dev_id)
+{
+ struct mpc52xx_lpbfifo_request *req;
+ u8 status = in_8(lpbfifo.regs + LPBFIFO_REG_BYTES_DONE_STATUS);
+ void __iomem *reg;
+ u32 *data;
+ int count, i;
+ int do_callback = 0;
+ u32 ts;
+ unsigned long flags;
+
+ spin_lock_irqsave(&lpbfifo.lock, flags);
+ ts = get_tbl();
+
+ req = lpbfifo.req;
+ if (!req) {
+ spin_unlock_irqrestore(&lpbfifo.lock, flags);
+ pr_err("bogus LPBFIFO IRQ\n");
+ return IRQ_HANDLED;
+ }
+
+ /*
+ * This is a tricky bit of code. There are 4 exit conditions:
+ * 1. FIFO abort
+ * 2. FIFO complete without DMA; more data to do
+ * 3. FIFO complete without DMA; all data transfered
+ * 4. FIFO complete using DMA
+ *
+ * Condition 1 can occur regardless of whether or not DMA is used.
+ * It requires executing the callback to report the error and exiting
+ * immediately.
+ *
+ * Condition 2 requires programming the FIFO with the next block of data
+ *
+ * Condition 3 requires executing the callback to report completion
+ *
+ * Condition 4 means the same as 3, except the callback must *not* be
+ * executed. Instead, execution of the callback is deferred to the DMA
+ * interrupt handler.
+ *
+ * To make things trickier, the spinlock must be dropped before
+ * executing the callback, otherwise we could end up with a deadlock
+ * or nested spinlock condition. The out path is non-trivial, so
+ * extra fiddling is done to make sure all paths lead to the same
+ * outbound code.
+ */
+
+ /* check abort bit */
+ if (status & 0x10) {
+ out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x01010000);
+ do_callback = 1;
+ goto out;
+ }
+
+ /* If using DMA, we should not be at this point */
+ if (!(req->flags & MPC52XX_LPBFIFO_FLAG_NO_DMA)) {
+ pr_err("bad IRQ mask? mask:%.8x status:%.8x flags=%x\n",
+ in_be32(lpbfifo.regs + LPBFIFO_REG_BYTES_DONE_STATUS),
+ status, req->flags);
+ goto out;
+ }
+
+ /* If the transaction done bit is *not* set; then why are we here? */
+ if ((status & 0x01) == 0) {
+ pr_err("spurious IRQ? %x\n", status);
+ goto out;
+ }
+
+ /* Read result from hardware */
+ count = in_be32(lpbfifo.regs + LPBFIFO_REG_BYTES_DONE_STATUS);
+ count &= 0x00ffffff;
+
+ /* copy the data out of the FIFO */
+ if (!(req->flags & MPC52XX_LPBFIFO_FLAG_WRITE)) {
+ reg = lpbfifo.regs + LPBFIFO_REG_FIFO_DATA;
+ data = req->data + req->pos;
+ for (i = 0; i < count; i += 4)
+ *data++ = in_be32(reg);
+ }
+
+ /* Update transfer position and count */
+ req->pos += count;
+
+ /* Decide what to do next */
+ if (req->size - req->pos)
+ mpc52xx_lpbfifo_kick(req); /* more work to do */
+ else
+ do_callback = 1;
+
+ out:
+ /* Clear the IRQ */
+ out_8(lpbfifo.regs + LPBFIFO_REG_BYTES_DONE_STATUS, 0x01);
+
+ /* When the do_callback flag is set; it means the transfer is finished
+ * so set the FIFO as idle */
+ if (do_callback)
+ lpbfifo.req = NULL;
+
+ /* Release the lock before calling out to the callback. */
+ req->irq_count++;
+ req->irq_ticks += get_tbl() - ts;
+ spin_unlock_irqrestore(&lpbfifo.lock, flags);
+
+ /* Spinlock is released; it is now safe to call the callback */
+ if (do_callback && req->callback)
+ req->callback(req);
+
+ return IRQ_HANDLED;
+}
+
+/**
+ * mpc52xx_lpbfifo_bcom_irq - IRQ handler for LPB FIFO Bestcomm task
+ */
+static irqreturn_t mpc52xx_lpbfifo_bcom_irq(int irq, void *dev_id)
+{
+ struct mpc52xx_lpbfifo_request *req;
+ unsigned long flags;
+ u32 status;
+ u32 ts;
+
+ spin_lock_irqsave(&lpbfifo.lock, flags);
+ ts = get_tbl();
+
+ req = lpbfifo.req;
+ if (!req) {
+ spin_unlock_irqrestore(&lpbfifo.lock, flags);
+ WARN_ONCE(1, "bogus Bestcomm IRQ\n");
+ return IRQ_HANDLED;
+ }
+
+ bcom_retrieve_buffer(lpbfifo.bcom_cur_task, &status, NULL);
+
+ req->pos = status & 0x00ffffff;
+
+ /* Mark the FIFO as idle */
+ lpbfifo.req = NULL;
+
+ /* Release the lock before calling out to the callback. */
+ req->irq_count++;
+ req->irq_ticks += get_tbl() - ts;
+ spin_unlock_irqrestore(&lpbfifo.lock, flags);
+
+ if (req->callback)
+ req->callback(req);
+
+ return IRQ_HANDLED;
+}
+
+
+/**
+ * mpc52xx_lpbfifo_submit - Submit an LPB FIFO transfer request.
+ * @req: Pointer to request structure
+ */
+int mpc52xx_lpbfifo_submit(struct mpc52xx_lpbfifo_request *req)
+{
+ unsigned long flags;
+
+ if (!lpbfifo.regs)
+ return -ENODEV;
+
+ spin_lock_irqsave(&lpbfifo.lock, flags);
+
+ /* If the req pointer is already set, then a transfer is in progress */
+ if (lpbfifo.req) {
+ spin_unlock_irqrestore(&lpbfifo.lock, flags);
+ return -EBUSY;
+ }
+
+ /* Setup the transfer */
+ lpbfifo.req = req;
+ req->irq_count = 0;
+ req->irq_ticks = 0;
+ req->pos = 0;
+
+ mpc52xx_lpbfifo_kick(req);
+ spin_unlock_irqrestore(&lpbfifo.lock, flags);
+ return 0;
+}
+EXPORT_SYMBOL(mpc52xx_lpbfifo_submit);
+
+void mpc52xx_lpbfifo_abort(struct mpc52xx_lpbfifo_request *req)
+{
+ unsigned long flags;
+
+ if (lpbfifo.req != req)
+ return;
+
+ spin_lock_irqsave(&lpbfifo.lock, flags);
+ /* Put it into reset and clear the state */
+ out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x01010000);
+ lpbfifo.req = NULL;
+ spin_unlock_irqrestore(&lpbfifo.lock, flags);
+}
+EXPORT_SYMBOL(mpc52xx_lpbfifo_abort);
+
+static int __devinit
+mpc52xx_lpbfifo_probe(struct of_device *op, const struct of_device_id *match)
+{
+ struct resource res;
+ int rc = -ENOMEM;
+
+ if (lpbfifo.dev != NULL)
+ return -ENOSPC;
+
+ lpbfifo.irq = irq_of_parse_and_map(op->node, 0);
+ if (!lpbfifo.irq)
+ return -ENODEV;
+
+ if (of_address_to_resource(op->node, 0, &res))
+ return -ENODEV;
+ lpbfifo.regs_phys = res.start;
+ lpbfifo.regs = of_iomap(op->node, 0);
+ if (!lpbfifo.regs)
+ return -ENOMEM;
+
+ spin_lock_init(&lpbfifo.lock);
+
+ /* Put FIFO into reset */
+ out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x01010000);
+
+ /* Configure the watermarks so DMA will always complete correctly.
+ * It may be worth experimenting with the ALARM value to see if
+ * there is a performance impacit. However, if it is wrong there
+ * is a risk of DMA not transferring the last chunk of data */
+ out_be32(lpbfifo.regs + LPBFIFO_REG_FIFO_ALARM, 0x1ff);
+ out_8(lpbfifo.regs + LPBFIFO_REG_FIFO_CONTROL, 0);
+
+ /* Register the interrupt handler */
+ rc = request_irq(lpbfifo.irq, mpc52xx_lpbfifo_irq, 0,
+ "mpc52xx-lpbfifo", &lpbfifo);
+ if (rc)
+ goto err_irq;
+
+ /* Request the Bestcomm receive (fifo --> memory) task and IRQ */
+ lpbfifo.bcom_rx_task =
+ bcom_gen_bd_rx_init(2, res.start + LPBFIFO_REG_FIFO_DATA,
+ BCOM_INITIATOR_SCLPC, BCOM_IPR_SCLPC,
+ 16*1024*1024);
+ if (!lpbfifo.bcom_rx_task)
+ goto err_bcom_rx;
+
+ rc = request_irq(bcom_get_task_irq(lpbfifo.bcom_rx_task),
+ mpc52xx_lpbfifo_bcom_irq, 0,
+ "mpc52xx-lpbfifo-rx", &lpbfifo);
+ if (rc)
+ goto err_bcom_rx_irq;
+
+ /* Request the Bestcomm transmit (memory --> fifo) task and IRQ */
+ lpbfifo.bcom_tx_task =
+ bcom_gen_bd_tx_init(2, res.start + LPBFIFO_REG_FIFO_DATA,
+ BCOM_INITIATOR_SCLPC, BCOM_IPR_SCLPC);
+ if (!lpbfifo.bcom_tx_task)
+ goto err_bcom_tx;
+
+ rc = request_irq(bcom_get_task_irq(lpbfifo.bcom_tx_task),
+ mpc52xx_lpbfifo_bcom_irq, 0,
+ "mpc52xx-lpbfifo-tx", &lpbfifo);
+ if (rc)
+ goto err_bcom_tx_irq;
+
+ lpbfifo.dev = &op->dev;
+ return 0;
+
+ err_bcom_tx_irq:
+ bcom_gen_bd_tx_release(lpbfifo.bcom_tx_task);
+ err_bcom_tx:
+ free_irq(bcom_get_task_irq(lpbfifo.bcom_rx_task), &lpbfifo);
+ err_bcom_rx_irq:
+ bcom_gen_bd_rx_release(lpbfifo.bcom_rx_task);
+ err_bcom_rx:
+ err_irq:
+ iounmap(lpbfifo.regs);
+ lpbfifo.regs = NULL;
+
+ dev_err(&op->dev, "mpc52xx_lpbfifo_probe() failed\n");
+ return -ENODEV;
+}
+
+
+static int __devexit mpc52xx_lpbfifo_remove(struct of_device *op)
+{
+ if (lpbfifo.dev != &op->dev)
+ return 0;
+
+ /* Put FIFO in reset */
+ out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x01010000);
+
+ /* Release the bestcomm transmit task */
+ free_irq(bcom_get_task_irq(lpbfifo.bcom_tx_task), &lpbfifo);
+ bcom_gen_bd_tx_release(lpbfifo.bcom_tx_task);
+
+ /* Release the bestcomm receive task */
+ free_irq(bcom_get_task_irq(lpbfifo.bcom_rx_task), &lpbfifo);
+ bcom_gen_bd_rx_release(lpbfifo.bcom_rx_task);
+
+ free_irq(lpbfifo.irq, &lpbfifo);
+ iounmap(lpbfifo.regs);
+ lpbfifo.regs = NULL;
+ lpbfifo.dev = NULL;
+
+ return 0;
+}
+
+static struct of_device_id mpc52xx_lpbfifo_match[] __devinitconst = {
+ { .compatible = "fsl,mpc5200-lpbfifo", },
+ {},
+};
+
+static struct of_platform_driver mpc52xx_lpbfifo_driver = {
+ .owner = THIS_MODULE,
+ .name = "mpc52xx-lpbfifo",
+ .match_table = mpc52xx_lpbfifo_match,
+ .probe = mpc52xx_lpbfifo_probe,
+ .remove = __devexit_p(mpc52xx_lpbfifo_remove),
+};
+
+/***********************************************************************
+ * Module init/exit
+ */
+static int __init mpc52xx_lpbfifo_init(void)
+{
+ pr_debug("Registering LocalPlus bus FIFO driver\n");
+ return of_register_platform_driver(&mpc52xx_lpbfifo_driver);
+}
+module_init(mpc52xx_lpbfifo_init);
+
+static void __exit mpc52xx_lpbfifo_exit(void)
+{
+ pr_debug("Unregistering LocalPlus bus FIFO driver\n");
+ of_unregister_platform_driver(&mpc52xx_lpbfifo_driver);
+}
+module_exit(mpc52xx_lpbfifo_exit);
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