blob: cec3f88f153d2cf1c9a4c23f8bf9c494ef3da09a [file] [log] [blame]
/*
* The driver for Freescale MPC512x LocalPlus Bus FIFO
* (called SCLPC in the Reference Manual).
*
* Copyright (C) 2013-2015 Alexander Popov <alex.popov@linux.com>.
*
* This file is released under the GPLv2.
*/
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <asm/mpc5121.h>
#include <asm/io.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/dmaengine.h>
#include <linux/dma-direction.h>
#include <linux/dma-mapping.h>
#define DRV_NAME "mpc512x_lpbfifo"
struct cs_range {
u32 csnum;
u32 base; /* must be zero */
u32 addr;
u32 size;
};
static struct lpbfifo_data {
spinlock_t lock; /* for protecting lpbfifo_data */
phys_addr_t regs_phys;
resource_size_t regs_size;
struct mpc512x_lpbfifo __iomem *regs;
int irq;
struct cs_range *cs_ranges;
size_t cs_n;
struct dma_chan *chan;
struct mpc512x_lpbfifo_request *req;
dma_addr_t ram_bus_addr;
bool wait_lpbfifo_irq;
bool wait_lpbfifo_callback;
} lpbfifo;
/*
* A data transfer from RAM to some device on LPB is finished
* when both mpc512x_lpbfifo_irq() and mpc512x_lpbfifo_callback()
* have been called. We execute the callback registered in
* mpc512x_lpbfifo_request just after that.
* But for a data transfer from some device on LPB to RAM we don't enable
* LPBFIFO interrupt because clearing MPC512X_SCLPC_SUCCESS interrupt flag
* automatically disables LPBFIFO reading request to the DMA controller
* and the data transfer hangs. So the callback registered in
* mpc512x_lpbfifo_request is executed at the end of mpc512x_lpbfifo_callback().
*/
/*
* mpc512x_lpbfifo_irq - IRQ handler for LPB FIFO
*/
static irqreturn_t mpc512x_lpbfifo_irq(int irq, void *param)
{
struct device *dev = (struct device *)param;
struct mpc512x_lpbfifo_request *req = NULL;
unsigned long flags;
u32 status;
spin_lock_irqsave(&lpbfifo.lock, flags);
if (!lpbfifo.regs)
goto end;
req = lpbfifo.req;
if (!req || req->dir == MPC512X_LPBFIFO_REQ_DIR_READ) {
dev_err(dev, "bogus LPBFIFO IRQ\n");
goto end;
}
status = in_be32(&lpbfifo.regs->status);
if (status != MPC512X_SCLPC_SUCCESS) {
dev_err(dev, "DMA transfer from RAM to peripheral failed\n");
out_be32(&lpbfifo.regs->enable,
MPC512X_SCLPC_RESET | MPC512X_SCLPC_FIFO_RESET);
goto end;
}
/* Clear the interrupt flag */
out_be32(&lpbfifo.regs->status, MPC512X_SCLPC_SUCCESS);
lpbfifo.wait_lpbfifo_irq = false;
if (lpbfifo.wait_lpbfifo_callback)
goto end;
/* Transfer is finished, set the FIFO as idle */
lpbfifo.req = NULL;
spin_unlock_irqrestore(&lpbfifo.lock, flags);
if (req->callback)
req->callback(req);
return IRQ_HANDLED;
end:
spin_unlock_irqrestore(&lpbfifo.lock, flags);
return IRQ_HANDLED;
}
/*
* mpc512x_lpbfifo_callback is called by DMA driver when
* DMA transaction is finished.
*/
static void mpc512x_lpbfifo_callback(void *param)
{
unsigned long flags;
struct mpc512x_lpbfifo_request *req = NULL;
enum dma_data_direction dir;
spin_lock_irqsave(&lpbfifo.lock, flags);
if (!lpbfifo.regs) {
spin_unlock_irqrestore(&lpbfifo.lock, flags);
return;
}
req = lpbfifo.req;
if (!req) {
pr_err("bogus LPBFIFO callback\n");
spin_unlock_irqrestore(&lpbfifo.lock, flags);
return;
}
/* Release the mapping */
if (req->dir == MPC512X_LPBFIFO_REQ_DIR_WRITE)
dir = DMA_TO_DEVICE;
else
dir = DMA_FROM_DEVICE;
dma_unmap_single(lpbfifo.chan->device->dev,
lpbfifo.ram_bus_addr, req->size, dir);
lpbfifo.wait_lpbfifo_callback = false;
if (!lpbfifo.wait_lpbfifo_irq) {
/* Transfer is finished, set the FIFO as idle */
lpbfifo.req = NULL;
spin_unlock_irqrestore(&lpbfifo.lock, flags);
if (req->callback)
req->callback(req);
} else {
spin_unlock_irqrestore(&lpbfifo.lock, flags);
}
}
static int mpc512x_lpbfifo_kick(void)
{
u32 bits;
bool no_incr = false;
u32 bpt = 32; /* max bytes per LPBFIFO transaction involving DMA */
u32 cs = 0;
size_t i;
struct dma_device *dma_dev = NULL;
struct scatterlist sg;
enum dma_data_direction dir;
struct dma_slave_config dma_conf = {};
struct dma_async_tx_descriptor *dma_tx = NULL;
dma_cookie_t cookie;
int ret;
/*
* 1. Fit the requirements:
* - the packet size must be a multiple of 4 since FIFO Data Word
* Register allows only full-word access according the Reference
* Manual;
* - the physical address of the device on LPB and the packet size
* must be aligned on BPT (bytes per transaction) or 8-bytes
* boundary according the Reference Manual;
* - but we choose DMA maxburst equal (or very close to) BPT to prevent
* DMA controller from overtaking FIFO and causing FIFO underflow
* error. So we force the packet size to be aligned on BPT boundary
* not to confuse DMA driver which requires the packet size to be
* aligned on maxburst boundary;
* - BPT should be set to the LPB device port size for operation with
* disabled auto-incrementing according Reference Manual.
*/
if (lpbfifo.req->size == 0 || !IS_ALIGNED(lpbfifo.req->size, 4))
return -EINVAL;
if (lpbfifo.req->portsize != LPB_DEV_PORTSIZE_UNDEFINED) {
bpt = lpbfifo.req->portsize;
no_incr = true;
}
while (bpt > 1) {
if (IS_ALIGNED(lpbfifo.req->dev_phys_addr, min(bpt, 0x8u)) &&
IS_ALIGNED(lpbfifo.req->size, bpt)) {
break;
}
if (no_incr)
return -EINVAL;
bpt >>= 1;
}
dma_conf.dst_maxburst = max(bpt, 0x4u) / 4;
dma_conf.src_maxburst = max(bpt, 0x4u) / 4;
for (i = 0; i < lpbfifo.cs_n; i++) {
phys_addr_t cs_start = lpbfifo.cs_ranges[i].addr;
phys_addr_t cs_end = cs_start + lpbfifo.cs_ranges[i].size;
phys_addr_t access_start = lpbfifo.req->dev_phys_addr;
phys_addr_t access_end = access_start + lpbfifo.req->size;
if (access_start >= cs_start && access_end <= cs_end) {
cs = lpbfifo.cs_ranges[i].csnum;
break;
}
}
if (i == lpbfifo.cs_n)
return -EFAULT;
/* 2. Prepare DMA */
dma_dev = lpbfifo.chan->device;
if (lpbfifo.req->dir == MPC512X_LPBFIFO_REQ_DIR_WRITE) {
dir = DMA_TO_DEVICE;
dma_conf.direction = DMA_MEM_TO_DEV;
dma_conf.dst_addr = lpbfifo.regs_phys +
offsetof(struct mpc512x_lpbfifo, data_word);
} else {
dir = DMA_FROM_DEVICE;
dma_conf.direction = DMA_DEV_TO_MEM;
dma_conf.src_addr = lpbfifo.regs_phys +
offsetof(struct mpc512x_lpbfifo, data_word);
}
dma_conf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
dma_conf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
/* Make DMA channel work with LPB FIFO data register */
if (dma_dev->device_config(lpbfifo.chan, &dma_conf)) {
ret = -EINVAL;
goto err_dma_prep;
}
sg_init_table(&sg, 1);
sg_dma_address(&sg) = dma_map_single(dma_dev->dev,
lpbfifo.req->ram_virt_addr, lpbfifo.req->size, dir);
if (dma_mapping_error(dma_dev->dev, sg_dma_address(&sg)))
return -EFAULT;
lpbfifo.ram_bus_addr = sg_dma_address(&sg); /* For freeing later */
sg_dma_len(&sg) = lpbfifo.req->size;
dma_tx = dmaengine_prep_slave_sg(lpbfifo.chan, &sg,
1, dma_conf.direction, 0);
if (!dma_tx) {
ret = -ENOSPC;
goto err_dma_prep;
}
dma_tx->callback = mpc512x_lpbfifo_callback;
dma_tx->callback_param = NULL;
/* 3. Prepare FIFO */
out_be32(&lpbfifo.regs->enable,
MPC512X_SCLPC_RESET | MPC512X_SCLPC_FIFO_RESET);
out_be32(&lpbfifo.regs->enable, 0x0);
/*
* Configure the watermarks for write operation (RAM->DMA->FIFO->dev):
* - high watermark 7 words according the Reference Manual,
* - low watermark 512 bytes (half of the FIFO).
* These watermarks don't work for read operation since the
* MPC512X_SCLPC_FLUSH bit is set (according the Reference Manual).
*/
out_be32(&lpbfifo.regs->fifo_ctrl, MPC512X_SCLPC_FIFO_CTRL(0x7));
out_be32(&lpbfifo.regs->fifo_alarm, MPC512X_SCLPC_FIFO_ALARM(0x200));
/*
* Start address is a physical address of the region which belongs
* to the device on the LocalPlus Bus
*/
out_be32(&lpbfifo.regs->start_addr, lpbfifo.req->dev_phys_addr);
/*
* Configure chip select, transfer direction, address increment option
* and bytes per transaction option
*/
bits = MPC512X_SCLPC_CS(cs);
if (lpbfifo.req->dir == MPC512X_LPBFIFO_REQ_DIR_READ)
bits |= MPC512X_SCLPC_READ | MPC512X_SCLPC_FLUSH;
if (no_incr)
bits |= MPC512X_SCLPC_DAI;
bits |= MPC512X_SCLPC_BPT(bpt);
out_be32(&lpbfifo.regs->ctrl, bits);
/* Unmask irqs */
bits = MPC512X_SCLPC_ENABLE | MPC512X_SCLPC_ABORT_INT_ENABLE;
if (lpbfifo.req->dir == MPC512X_LPBFIFO_REQ_DIR_WRITE)
bits |= MPC512X_SCLPC_NORM_INT_ENABLE;
else
lpbfifo.wait_lpbfifo_irq = false;
out_be32(&lpbfifo.regs->enable, bits);
/* 4. Set packet size and kick FIFO off */
bits = lpbfifo.req->size | MPC512X_SCLPC_START;
out_be32(&lpbfifo.regs->pkt_size, bits);
/* 5. Finally kick DMA off */
cookie = dma_tx->tx_submit(dma_tx);
if (dma_submit_error(cookie)) {
ret = -ENOSPC;
goto err_dma_submit;
}
return 0;
err_dma_submit:
out_be32(&lpbfifo.regs->enable,
MPC512X_SCLPC_RESET | MPC512X_SCLPC_FIFO_RESET);
err_dma_prep:
dma_unmap_single(dma_dev->dev, sg_dma_address(&sg),
lpbfifo.req->size, dir);
return ret;
}
static int mpc512x_lpbfifo_submit_locked(struct mpc512x_lpbfifo_request *req)
{
int ret = 0;
if (!lpbfifo.regs)
return -ENODEV;
/* Check whether a transfer is in progress */
if (lpbfifo.req)
return -EBUSY;
lpbfifo.wait_lpbfifo_irq = true;
lpbfifo.wait_lpbfifo_callback = true;
lpbfifo.req = req;
ret = mpc512x_lpbfifo_kick();
if (ret != 0)
lpbfifo.req = NULL; /* Set the FIFO as idle */
return ret;
}
int mpc512x_lpbfifo_submit(struct mpc512x_lpbfifo_request *req)
{
unsigned long flags;
int ret = 0;
spin_lock_irqsave(&lpbfifo.lock, flags);
ret = mpc512x_lpbfifo_submit_locked(req);
spin_unlock_irqrestore(&lpbfifo.lock, flags);
return ret;
}
EXPORT_SYMBOL(mpc512x_lpbfifo_submit);
/*
* LPBFIFO driver uses "ranges" property of "localbus" device tree node
* for being able to determine the chip select number of a client device
* ordering a DMA transfer.
*/
static int get_cs_ranges(struct device *dev)
{
int ret = -ENODEV;
struct device_node *lb_node;
const u32 *addr_cells_p;
const u32 *size_cells_p;
int proplen;
size_t i;
lb_node = of_find_compatible_node(NULL, NULL, "fsl,mpc5121-localbus");
if (!lb_node)
return ret;
/*
* The node defined as compatible with 'fsl,mpc5121-localbus'
* should have two address cells and one size cell.
* Every item of its ranges property should consist of:
* - the first address cell which is the chipselect number;
* - the second address cell which is the offset in the chipselect,
* must be zero.
* - CPU address of the beginning of an access window;
* - the only size cell which is the size of an access window.
*/
addr_cells_p = of_get_property(lb_node, "#address-cells", NULL);
size_cells_p = of_get_property(lb_node, "#size-cells", NULL);
if (addr_cells_p == NULL || *addr_cells_p != 2 ||
size_cells_p == NULL || *size_cells_p != 1) {
goto end;
}
proplen = of_property_count_u32_elems(lb_node, "ranges");
if (proplen <= 0 || proplen % 4 != 0)
goto end;
lpbfifo.cs_n = proplen / 4;
lpbfifo.cs_ranges = devm_kcalloc(dev, lpbfifo.cs_n,
sizeof(struct cs_range), GFP_KERNEL);
if (!lpbfifo.cs_ranges)
goto end;
if (of_property_read_u32_array(lb_node, "ranges",
(u32 *)lpbfifo.cs_ranges, proplen) != 0) {
goto end;
}
for (i = 0; i < lpbfifo.cs_n; i++) {
if (lpbfifo.cs_ranges[i].base != 0)
goto end;
}
ret = 0;
end:
of_node_put(lb_node);
return ret;
}
static int mpc512x_lpbfifo_probe(struct platform_device *pdev)
{
struct resource r;
int ret = 0;
memset(&lpbfifo, 0, sizeof(struct lpbfifo_data));
spin_lock_init(&lpbfifo.lock);
lpbfifo.chan = dma_request_slave_channel(&pdev->dev, "rx-tx");
if (lpbfifo.chan == NULL)
return -EPROBE_DEFER;
if (of_address_to_resource(pdev->dev.of_node, 0, &r) != 0) {
dev_err(&pdev->dev, "bad 'reg' in 'sclpc' device tree node\n");
ret = -ENODEV;
goto err0;
}
lpbfifo.regs_phys = r.start;
lpbfifo.regs_size = resource_size(&r);
if (!devm_request_mem_region(&pdev->dev, lpbfifo.regs_phys,
lpbfifo.regs_size, DRV_NAME)) {
dev_err(&pdev->dev, "unable to request region\n");
ret = -EBUSY;
goto err0;
}
lpbfifo.regs = devm_ioremap(&pdev->dev,
lpbfifo.regs_phys, lpbfifo.regs_size);
if (!lpbfifo.regs) {
dev_err(&pdev->dev, "mapping registers failed\n");
ret = -ENOMEM;
goto err0;
}
out_be32(&lpbfifo.regs->enable,
MPC512X_SCLPC_RESET | MPC512X_SCLPC_FIFO_RESET);
if (get_cs_ranges(&pdev->dev) != 0) {
dev_err(&pdev->dev, "bad '/localbus' device tree node\n");
ret = -ENODEV;
goto err0;
}
lpbfifo.irq = irq_of_parse_and_map(pdev->dev.of_node, 0);
if (!lpbfifo.irq) {
dev_err(&pdev->dev, "mapping irq failed\n");
ret = -ENODEV;
goto err0;
}
if (request_irq(lpbfifo.irq, mpc512x_lpbfifo_irq, 0,
DRV_NAME, &pdev->dev) != 0) {
dev_err(&pdev->dev, "requesting irq failed\n");
ret = -ENODEV;
goto err1;
}
dev_info(&pdev->dev, "probe succeeded\n");
return 0;
err1:
irq_dispose_mapping(lpbfifo.irq);
err0:
dma_release_channel(lpbfifo.chan);
return ret;
}
static int mpc512x_lpbfifo_remove(struct platform_device *pdev)
{
unsigned long flags;
struct dma_device *dma_dev = lpbfifo.chan->device;
struct mpc512x_lpbfifo __iomem *regs = NULL;
spin_lock_irqsave(&lpbfifo.lock, flags);
regs = lpbfifo.regs;
lpbfifo.regs = NULL;
spin_unlock_irqrestore(&lpbfifo.lock, flags);
dma_dev->device_terminate_all(lpbfifo.chan);
out_be32(&regs->enable, MPC512X_SCLPC_RESET | MPC512X_SCLPC_FIFO_RESET);
free_irq(lpbfifo.irq, &pdev->dev);
irq_dispose_mapping(lpbfifo.irq);
dma_release_channel(lpbfifo.chan);
return 0;
}
static const struct of_device_id mpc512x_lpbfifo_match[] = {
{ .compatible = "fsl,mpc512x-lpbfifo", },
{},
};
MODULE_DEVICE_TABLE(of, mpc512x_lpbfifo_match);
static struct platform_driver mpc512x_lpbfifo_driver = {
.probe = mpc512x_lpbfifo_probe,
.remove = mpc512x_lpbfifo_remove,
.driver = {
.name = DRV_NAME,
.of_match_table = mpc512x_lpbfifo_match,
},
};
module_platform_driver(mpc512x_lpbfifo_driver);
MODULE_AUTHOR("Alexander Popov <alex.popov@linux.com>");
MODULE_DESCRIPTION("MPC512x LocalPlus Bus FIFO device driver");
MODULE_LICENSE("GPL v2");