| /* |
| * arch/arm/plat-spear/pl080.c |
| * |
| * DMAC pl080 definitions for SPEAr platform |
| * |
| * Copyright (C) 2012 ST Microelectronics |
| * Viresh Kumar <vireshk@kernel.org> |
| * |
| * This file is licensed under the terms of the GNU General Public |
| * License version 2. This program is licensed "as is" without any |
| * warranty of any kind, whether express or implied. |
| */ |
| |
| #include <linux/amba/pl08x.h> |
| #include <linux/amba/bus.h> |
| #include <linux/bug.h> |
| #include <linux/err.h> |
| #include <linux/io.h> |
| #include <linux/spinlock_types.h> |
| #include "spear.h" |
| #include "misc_regs.h" |
| |
| static spinlock_t lock = __SPIN_LOCK_UNLOCKED(x); |
| |
| struct { |
| unsigned char busy; |
| unsigned char val; |
| } signals[16] = {{0, 0}, }; |
| |
| int pl080_get_signal(const struct pl08x_channel_data *cd) |
| { |
| unsigned int signal = cd->min_signal, val; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&lock, flags); |
| |
| /* Return if signal is already acquired by somebody else */ |
| if (signals[signal].busy && |
| (signals[signal].val != cd->muxval)) { |
| spin_unlock_irqrestore(&lock, flags); |
| return -EBUSY; |
| } |
| |
| /* If acquiring for the first time, configure it */ |
| if (!signals[signal].busy) { |
| val = readl(DMA_CHN_CFG); |
| |
| /* |
| * Each request line has two bits in DMA_CHN_CFG register. To |
| * goto the bits of current request line, do left shift of |
| * value by 2 * signal number. |
| */ |
| val &= ~(0x3 << (signal * 2)); |
| val |= cd->muxval << (signal * 2); |
| writel(val, DMA_CHN_CFG); |
| } |
| |
| signals[signal].busy++; |
| signals[signal].val = cd->muxval; |
| spin_unlock_irqrestore(&lock, flags); |
| |
| return signal; |
| } |
| |
| void pl080_put_signal(const struct pl08x_channel_data *cd, int signal) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&lock, flags); |
| |
| /* if signal is not used */ |
| if (!signals[signal].busy) |
| BUG(); |
| |
| signals[signal].busy--; |
| |
| spin_unlock_irqrestore(&lock, flags); |
| } |