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// SPDX-License-Identifier: GPL-2.0
/* ebus.c: EBUS DMA library code.
*
* Copyright (C) 1997 Eddie C. Dost (ecd@skynet.be)
* Copyright (C) 1999 David S. Miller (davem@redhat.com)
*/
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <asm/ebus_dma.h>
#include <asm/io.h>
#define EBDMA_CSR 0x00UL /* Control/Status */
#define EBDMA_ADDR 0x04UL /* DMA Address */
#define EBDMA_COUNT 0x08UL /* DMA Count */
#define EBDMA_CSR_INT_PEND 0x00000001
#define EBDMA_CSR_ERR_PEND 0x00000002
#define EBDMA_CSR_DRAIN 0x00000004
#define EBDMA_CSR_INT_EN 0x00000010
#define EBDMA_CSR_RESET 0x00000080
#define EBDMA_CSR_WRITE 0x00000100
#define EBDMA_CSR_EN_DMA 0x00000200
#define EBDMA_CSR_CYC_PEND 0x00000400
#define EBDMA_CSR_DIAG_RD_DONE 0x00000800
#define EBDMA_CSR_DIAG_WR_DONE 0x00001000
#define EBDMA_CSR_EN_CNT 0x00002000
#define EBDMA_CSR_TC 0x00004000
#define EBDMA_CSR_DIS_CSR_DRN 0x00010000
#define EBDMA_CSR_BURST_SZ_MASK 0x000c0000
#define EBDMA_CSR_BURST_SZ_1 0x00080000
#define EBDMA_CSR_BURST_SZ_4 0x00000000
#define EBDMA_CSR_BURST_SZ_8 0x00040000
#define EBDMA_CSR_BURST_SZ_16 0x000c0000
#define EBDMA_CSR_DIAG_EN 0x00100000
#define EBDMA_CSR_DIS_ERR_PEND 0x00400000
#define EBDMA_CSR_TCI_DIS 0x00800000
#define EBDMA_CSR_EN_NEXT 0x01000000
#define EBDMA_CSR_DMA_ON 0x02000000
#define EBDMA_CSR_A_LOADED 0x04000000
#define EBDMA_CSR_NA_LOADED 0x08000000
#define EBDMA_CSR_DEV_ID_MASK 0xf0000000
#define EBUS_DMA_RESET_TIMEOUT 10000
static void __ebus_dma_reset(struct ebus_dma_info *p, int no_drain)
{
int i;
u32 val = 0;
writel(EBDMA_CSR_RESET, p->regs + EBDMA_CSR);
udelay(1);
if (no_drain)
return;
for (i = EBUS_DMA_RESET_TIMEOUT; i > 0; i--) {
val = readl(p->regs + EBDMA_CSR);
if (!(val & (EBDMA_CSR_DRAIN | EBDMA_CSR_CYC_PEND)))
break;
udelay(10);
}
}
static irqreturn_t ebus_dma_irq(int irq, void *dev_id)
{
struct ebus_dma_info *p = dev_id;
unsigned long flags;
u32 csr = 0;
spin_lock_irqsave(&p->lock, flags);
csr = readl(p->regs + EBDMA_CSR);
writel(csr, p->regs + EBDMA_CSR);
spin_unlock_irqrestore(&p->lock, flags);
if (csr & EBDMA_CSR_ERR_PEND) {
printk(KERN_CRIT "ebus_dma(%s): DMA error!\n", p->name);
p->callback(p, EBUS_DMA_EVENT_ERROR, p->client_cookie);
return IRQ_HANDLED;
} else if (csr & EBDMA_CSR_INT_PEND) {
p->callback(p,
(csr & EBDMA_CSR_TC) ?
EBUS_DMA_EVENT_DMA : EBUS_DMA_EVENT_DEVICE,
p->client_cookie);
return IRQ_HANDLED;
}
return IRQ_NONE;
}
int ebus_dma_register(struct ebus_dma_info *p)
{
u32 csr;
if (!p->regs)
return -EINVAL;
if (p->flags & ~(EBUS_DMA_FLAG_USE_EBDMA_HANDLER |
EBUS_DMA_FLAG_TCI_DISABLE))
return -EINVAL;
if ((p->flags & EBUS_DMA_FLAG_USE_EBDMA_HANDLER) && !p->callback)
return -EINVAL;
if (!strlen(p->name))
return -EINVAL;
__ebus_dma_reset(p, 1);
csr = EBDMA_CSR_BURST_SZ_16 | EBDMA_CSR_EN_CNT;
if (p->flags & EBUS_DMA_FLAG_TCI_DISABLE)
csr |= EBDMA_CSR_TCI_DIS;
writel(csr, p->regs + EBDMA_CSR);
return 0;
}
EXPORT_SYMBOL(ebus_dma_register);
int ebus_dma_irq_enable(struct ebus_dma_info *p, int on)
{
unsigned long flags;
u32 csr;
if (on) {
if (p->flags & EBUS_DMA_FLAG_USE_EBDMA_HANDLER) {
if (request_irq(p->irq, ebus_dma_irq, IRQF_SHARED, p->name, p))
return -EBUSY;
}
spin_lock_irqsave(&p->lock, flags);
csr = readl(p->regs + EBDMA_CSR);
csr |= EBDMA_CSR_INT_EN;
writel(csr, p->regs + EBDMA_CSR);
spin_unlock_irqrestore(&p->lock, flags);
} else {
spin_lock_irqsave(&p->lock, flags);
csr = readl(p->regs + EBDMA_CSR);
csr &= ~EBDMA_CSR_INT_EN;
writel(csr, p->regs + EBDMA_CSR);
spin_unlock_irqrestore(&p->lock, flags);
if (p->flags & EBUS_DMA_FLAG_USE_EBDMA_HANDLER) {
free_irq(p->irq, p);
}
}
return 0;
}
EXPORT_SYMBOL(ebus_dma_irq_enable);
void ebus_dma_unregister(struct ebus_dma_info *p)
{
unsigned long flags;
u32 csr;
int irq_on = 0;
spin_lock_irqsave(&p->lock, flags);
csr = readl(p->regs + EBDMA_CSR);
if (csr & EBDMA_CSR_INT_EN) {
csr &= ~EBDMA_CSR_INT_EN;
writel(csr, p->regs + EBDMA_CSR);
irq_on = 1;
}
spin_unlock_irqrestore(&p->lock, flags);
if (irq_on)
free_irq(p->irq, p);
}
EXPORT_SYMBOL(ebus_dma_unregister);
int ebus_dma_request(struct ebus_dma_info *p, dma_addr_t bus_addr, size_t len)
{
unsigned long flags;
u32 csr;
int err;
if (len >= (1 << 24))
return -EINVAL;
spin_lock_irqsave(&p->lock, flags);
csr = readl(p->regs + EBDMA_CSR);
err = -EINVAL;
if (!(csr & EBDMA_CSR_EN_DMA))
goto out;
err = -EBUSY;
if (csr & EBDMA_CSR_NA_LOADED)
goto out;
writel(len, p->regs + EBDMA_COUNT);
writel(bus_addr, p->regs + EBDMA_ADDR);
err = 0;
out:
spin_unlock_irqrestore(&p->lock, flags);
return err;
}
EXPORT_SYMBOL(ebus_dma_request);
void ebus_dma_prepare(struct ebus_dma_info *p, int write)
{
unsigned long flags;
u32 csr;
spin_lock_irqsave(&p->lock, flags);
__ebus_dma_reset(p, 0);
csr = (EBDMA_CSR_INT_EN |
EBDMA_CSR_EN_CNT |
EBDMA_CSR_BURST_SZ_16 |
EBDMA_CSR_EN_NEXT);
if (write)
csr |= EBDMA_CSR_WRITE;
if (p->flags & EBUS_DMA_FLAG_TCI_DISABLE)
csr |= EBDMA_CSR_TCI_DIS;
writel(csr, p->regs + EBDMA_CSR);
spin_unlock_irqrestore(&p->lock, flags);
}
EXPORT_SYMBOL(ebus_dma_prepare);
unsigned int ebus_dma_residue(struct ebus_dma_info *p)
{
return readl(p->regs + EBDMA_COUNT);
}
EXPORT_SYMBOL(ebus_dma_residue);
unsigned int ebus_dma_addr(struct ebus_dma_info *p)
{
return readl(p->regs + EBDMA_ADDR);
}
EXPORT_SYMBOL(ebus_dma_addr);
void ebus_dma_enable(struct ebus_dma_info *p, int on)
{
unsigned long flags;
u32 orig_csr, csr;
spin_lock_irqsave(&p->lock, flags);
orig_csr = csr = readl(p->regs + EBDMA_CSR);
if (on)
csr |= EBDMA_CSR_EN_DMA;
else
csr &= ~EBDMA_CSR_EN_DMA;
if ((orig_csr & EBDMA_CSR_EN_DMA) !=
(csr & EBDMA_CSR_EN_DMA))
writel(csr, p->regs + EBDMA_CSR);
spin_unlock_irqrestore(&p->lock, flags);
}
EXPORT_SYMBOL(ebus_dma_enable);
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