// SPDX-License-Identifier: GPL-2.0-only
/*
* LocalPlus Bus FIFO driver for the Freescale MPC52xx.
*
* Copyright (C) 2009 Secret Lab Technologies Ltd.
*
* 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 <linux/module.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/mpc52xx.h>
#include <asm/time.h>
#include <linux/fsl/bestcomm/bestcomm.h>
#include <linux/fsl/bestcomm/bestcomm_priv.h>
#include <linux/fsl/bestcomm/gen_bd.h>
MODULE_AUTHOR("Grant Likely <grant.likely@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;
int dma_irqs_enabled;
};
/* 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 transferred
*/
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;
int bit_fields;
int dma = !(req->flags & MPC52XX_LPBFIFO_FLAG_NO_DMA);
int write = req->flags & MPC52XX_LPBFIFO_FLAG_WRITE;
int poll_dma = req->flags & MPC52XX_LPBFIFO_FLAG_POLL_DMA;
/* Set and clear the reset bits; is good practice in User Manual */
out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x01010000);
/* set master enable bit */
out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x00000001);
if (!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 (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
*
* 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
*/
if (write) {
out_be32(lpbfifo.regs + LPBFIFO_REG_FIFO_ALARM, 0x1e4);
out_8(lpbfifo.regs + LPBFIFO_REG_FIFO_CONTROL, 7);
lpbfifo.bcom_cur_task = lpbfifo.bcom_tx_task;
} else {
out_be32(lpbfifo.regs + LPBFIFO_REG_FIFO_ALARM, 0x1ff);
out_8(lpbfifo.regs + LPBFIFO_REG_FIFO_CONTROL, 0);
lpbfifo.bcom_cur_task = lpbfifo.bcom_rx_task;
if (poll_dma) {
if (lpbfifo.dma_irqs_enabled) {
disable_irq(bcom_get_task_irq(lpbfifo.bcom_rx_task));
lpbfifo.dma_irqs_enabled = 0;
}
} else {
if (!lpbfifo.dma_irqs_enabled) {
enable_irq(bcom_get_task_irq(lpbfifo.bcom_rx_task));
lpbfifo.dma_irqs_enabled = 1;
}
}
}
bd = bcom_prepare_next_buffer(lpbfifo.bcom_cur_task);
bd->status = transfer_size;
if (!write) {
/*
* In the DMA read case, the DMA doesn't complete,
* possibly due to incorrect watermarks in the ALARM
* and CONTROL regs. For now instead of trying to
* determine the right watermarks that will make this
* work, just increase the number of bytes the FIFO is
* expecting.
*
* When submitting another operation, the FIFO will get
* reset, so the condition of the FIFO waiting for a
* non-existent 4 bytes will get cleared.
*/
transfer_size += 4; /* BLECH! */
}
bd->data[0] = req->data_phys + req->pos;
bcom_submit_next_buffer(lpbfifo.bcom_cur_task, NULL);
/* error irq & master enabled bit */
bit_fields = 0x00000201;
/* Unmask irqs */
if (write && (!poll_dma))
bit_fields |= 0x00000100; /* completion irq too */
out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, bit_fields);
}
/* 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);
bit_fields = req->cs << 24 | 0x000008;
if (!write)
bit_fields |= 0x010000; /* read mode */
out_be32(lpbfifo.regs + LPBFIFO_REG_CONTROL, bit_fields);
/* Kick it off */
if (!lpbfifo.req->defer_xfer_start)
out_8(lpbfifo.regs + LPBFIFO_REG_PACKET_SIZE, 0x01);
if (dma)
bcom_enable(lpbfifo.bcom_cur_task);
}
/**
* mpc52xx_lpbfifo_irq - IRQ handler for LPB FIFO
*
* On transmit, the dma completion irq triggers before the fifo completion
* triggers. Handle the dma completion here instead of the LPB FIFO Bestcomm
* task completion irq because everything is not really done until the LPB FIFO
* completion irq triggers.
*
* In other words:
* For DMA, on receive, the "Fat Lady" is the bestcom completion irq. on
* transmit, the fifo completion irq is the "Fat Lady". The opera (or in this
* case the DMA/FIFO operation) is not finished until the "Fat Lady" sings.
*
* Reasons for entering this routine:
* 1) PIO mode rx and tx completion irq
* 2) DMA interrupt mode tx completion irq
* 3) DMA polled mode tx
*
* Exit conditions:
* 1) Transfer aborted
* 2) FIFO complete without DMA; more data to do
* 3) FIFO complete without DMA; all data transferred
* 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 that we also retrieve the bcom
* buffer so DMA doesn't get clogged up.
*
* 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.
*/
static irqreturn_t mpc52xx_lpbfifo_irq(int irq, void *dev_id)
{
struct mpc52xx_lpbfifo_request *req;
u32 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;
int dma, write, poll_dma;
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;
}
dma = !(req->flags & MPC52XX_LPBFIFO_FLAG_NO_DMA);
write = req->flags & MPC52XX_LPBFIFO_FLAG_WRITE;
poll_dma = req->flags & MPC52XX_LPBFIFO_FLAG_POLL_DMA;
if (dma && !write) {
spin_unlock_irqrestore(&lpbfifo.lock, flags);
pr_err("bogus LPBFIFO IRQ (dma and not writing)\n");
return IRQ_HANDLED;
}
if ((status & 0x01) == 0) {
goto out;
}
/* check abort bit */
if (status & 0x10) {
out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x01010000);
do_callback = 1;
goto out;
}
/* Read result from hardware */
count = in_be32(lpbfifo.regs + LPBFIFO_REG_BYTES_DONE_STATUS);
count &= 0x00ffffff;
if (!dma && !write) {
/* copy the data out of the FIFO */
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);
if (dma && (status & 0x11)) {
/*
* Count the DMA as complete only when the FIFO completion
* status or abort bits are set.
*
* (status & 0x01) should always be the case except sometimes
* when using polled DMA.
*
* (status & 0x10) {transfer aborted}: This case needs more
* testing.
*/
bcom_retrieve_buffer(lpbfifo.bcom_cur_task, &status, NULL);
}
req->last_byte = ((u8 *)req->data)[req->size - 1];
/* 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;
if (irq != 0) /* don't increment on polled case */
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
*
* Only used when receiving data.
*/
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 || (req->flags & MPC52XX_LPBFIFO_FLAG_NO_DMA)) {
spin_unlock_irqrestore(&lpbfifo.lock, flags);
return IRQ_HANDLED;
}
if (irq != 0) /* don't increment on polled case */
req->irq_count++;
if (!bcom_buffer_done(lpbfifo.bcom_cur_task)) {
spin_unlock_irqrestore(&lpbfifo.lock, flags);
req->buffer_not_done_cnt++;
if ((req->buffer_not_done_cnt % 1000) == 0)
pr_err("transfer stalled\n");
return IRQ_HANDLED;
}
bcom_retrieve_buffer(lpbfifo.bcom_cur_task, &status, NULL);
req->last_byte = ((u8 *)req->data)[req->size - 1];
req->pos = status & 0x00ffffff;
/* Mark the FIFO as idle */
lpbfifo.req = NULL;
/* Release the lock before calling out to the callback. */
req->irq_ticks += get_tbl() - ts;
spin_unlock_irqrestore(&lpbfifo.lock, flags);
if (req->callback)
req->callback(req);
return IRQ_HANDLED;
}
/**
* mpc52xx_lpbfifo_bcom_poll - Poll for DMA completion
*/
void mpc52xx_lpbfifo_poll(void)
{
struct mpc52xx_lpbfifo_request *req = lpbfifo.req;
int dma = !(req->flags & MPC52XX_LPBFIFO_FLAG_NO_DMA);
int write = req->flags & MPC52XX_LPBFIFO_FLAG_WRITE;
/*
* For more information, see comments on the "Fat Lady"
*/
if (dma && write)
mpc52xx_lpbfifo_irq(0, NULL);
else
mpc52xx_lpbfifo_bcom_irq(0, NULL);
}
EXPORT_SYMBOL(mpc52xx_lpbfifo_poll);
/**
* 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->buffer_not_done_cnt = 0;
req->pos = 0;
mpc52xx_lpbfifo_kick(req);
spin_unlock_irqrestore(&lpbfifo.lock, flags);
return 0;
}
EXPORT_SYMBOL(mpc52xx_lpbfifo_submit);
int mpc52xx_lpbfifo_start_xfer(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 and a transfer was
* started on submit, then this transfer is in progress
*/
if (lpbfifo.req && !lpbfifo.req->defer_xfer_start) {
spin_unlock_irqrestore(&lpbfifo.lock, flags);
return -EBUSY;
}
/*
* If the req was previously submitted but not
* started, start it now
*/
if (lpbfifo.req && lpbfifo.req == req &&
lpbfifo.req->defer_xfer_start) {
out_8(lpbfifo.regs + LPBFIFO_REG_PACKET_SIZE, 0x01);
}
spin_unlock_irqrestore(&lpbfifo.lock, flags);
return 0;
}
EXPORT_SYMBOL(mpc52xx_lpbfifo_start_xfer);
void mpc52xx_lpbfifo_abort(struct mpc52xx_lpbfifo_request *req)
{
unsigned long flags;
spin_lock_irqsave(&lpbfifo.lock, flags);
if (lpbfifo.req == req) {
/* Put it into reset and clear the state */
bcom_gen_bd_rx_reset(lpbfifo.bcom_rx_task);
bcom_gen_bd_tx_reset(lpbfifo.bcom_tx_task);
out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x01010000);
lpbfifo.req = NULL;
}
spin_unlock_irqrestore(&lpbfifo.lock, flags);
}
EXPORT_SYMBOL(mpc52xx_lpbfifo_abort);
static int mpc52xx_lpbfifo_probe(struct platform_device *op)
{
struct resource res;
int rc = -ENOMEM;
if (lpbfifo.dev != NULL)
return -ENOSPC;
lpbfifo.irq = irq_of_parse_and_map(op->dev.of_node, 0);
if (!lpbfifo.irq)
return -ENODEV;
if (of_address_to_resource(op->dev.of_node, 0, &res))
return -ENODEV;
lpbfifo.regs_phys = res.start;
lpbfifo.regs = of_iomap(op->dev.of_node, 0);
if (!lpbfifo.regs)
return -ENOMEM;
spin_lock_init(&lpbfifo.lock);
/* Put FIFO into reset */
out_be32(lpbfifo.regs + LPBFIFO_REG_ENABLE, 0x01010000);
/* 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;
lpbfifo.dma_irqs_enabled = 1;
/* 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;
lpbfifo.dev = &op->dev;
return 0;
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 mpc52xx_lpbfifo_remove(struct platform_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 const struct of_device_id mpc52xx_lpbfifo_match[] = {
{ .compatible = "fsl,mpc5200-lpbfifo", },
{},
};
MODULE_DEVICE_TABLE(of, mpc52xx_lpbfifo_match);
static struct platform_driver mpc52xx_lpbfifo_driver = {
.driver = {
.name = "mpc52xx-lpbfifo",
.of_match_table = mpc52xx_lpbfifo_match,
},
.probe = mpc52xx_lpbfifo_probe,
.remove = mpc52xx_lpbfifo_remove,
};
module_platform_driver(mpc52xx_lpbfifo_driver);
