diff options
Diffstat (limited to 'arch/arm/mach-omap1/fpga.c')
| -rw-r--r-- | arch/arm/mach-omap1/fpga.c | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/arch/arm/mach-omap1/fpga.c b/arch/arm/mach-omap1/fpga.c new file mode 100644 index 000000000..4c71a1959 --- /dev/null +++ b/arch/arm/mach-omap1/fpga.c @@ -0,0 +1,186 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * linux/arch/arm/mach-omap1/fpga.c + * + * Interrupt handler for OMAP-1510 Innovator FPGA + * + * Copyright (C) 2001 RidgeRun, Inc. + * Author: Greg Lonnon <glonnon@ridgerun.com> + * + * Copyright (C) 2002 MontaVista Software, Inc. + * + * Separated FPGA interrupts from innovator1510.c and cleaned up for 2.6 + * Copyright (C) 2004 Nokia Corporation by Tony Lindrgen <tony@atomide.com> + */ + +#include <linux/types.h> +#include <linux/gpio.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/device.h> +#include <linux/errno.h> +#include <linux/io.h> + +#include <asm/irq.h> +#include <asm/mach/irq.h> + +#include "hardware.h" +#include "iomap.h" +#include "common.h" +#include "fpga.h" + +static void fpga_mask_irq(struct irq_data *d) +{ + unsigned int irq = d->irq - OMAP_FPGA_IRQ_BASE; + + if (irq < 8) + __raw_writeb((__raw_readb(OMAP1510_FPGA_IMR_LO) + & ~(1 << irq)), OMAP1510_FPGA_IMR_LO); + else if (irq < 16) + __raw_writeb((__raw_readb(OMAP1510_FPGA_IMR_HI) + & ~(1 << (irq - 8))), OMAP1510_FPGA_IMR_HI); + else + __raw_writeb((__raw_readb(INNOVATOR_FPGA_IMR2) + & ~(1 << (irq - 16))), INNOVATOR_FPGA_IMR2); +} + + +static inline u32 get_fpga_unmasked_irqs(void) +{ + return + ((__raw_readb(OMAP1510_FPGA_ISR_LO) & + __raw_readb(OMAP1510_FPGA_IMR_LO))) | + ((__raw_readb(OMAP1510_FPGA_ISR_HI) & + __raw_readb(OMAP1510_FPGA_IMR_HI)) << 8) | + ((__raw_readb(INNOVATOR_FPGA_ISR2) & + __raw_readb(INNOVATOR_FPGA_IMR2)) << 16); +} + + +static void fpga_ack_irq(struct irq_data *d) +{ + /* Don't need to explicitly ACK FPGA interrupts */ +} + +static void fpga_unmask_irq(struct irq_data *d) +{ + unsigned int irq = d->irq - OMAP_FPGA_IRQ_BASE; + + if (irq < 8) + __raw_writeb((__raw_readb(OMAP1510_FPGA_IMR_LO) | (1 << irq)), + OMAP1510_FPGA_IMR_LO); + else if (irq < 16) + __raw_writeb((__raw_readb(OMAP1510_FPGA_IMR_HI) + | (1 << (irq - 8))), OMAP1510_FPGA_IMR_HI); + else + __raw_writeb((__raw_readb(INNOVATOR_FPGA_IMR2) + | (1 << (irq - 16))), INNOVATOR_FPGA_IMR2); +} + +static void fpga_mask_ack_irq(struct irq_data *d) +{ + fpga_mask_irq(d); + fpga_ack_irq(d); +} + +static void innovator_fpga_IRQ_demux(struct irq_desc *desc) +{ + u32 stat; + int fpga_irq; + + stat = get_fpga_unmasked_irqs(); + + if (!stat) + return; + + for (fpga_irq = OMAP_FPGA_IRQ_BASE; + (fpga_irq < OMAP_FPGA_IRQ_END) && stat; + fpga_irq++, stat >>= 1) { + if (stat & 1) { + generic_handle_irq(fpga_irq); + } + } +} + +static struct irq_chip omap_fpga_irq_ack = { + .name = "FPGA-ack", + .irq_ack = fpga_mask_ack_irq, + .irq_mask = fpga_mask_irq, + .irq_unmask = fpga_unmask_irq, +}; + + +static struct irq_chip omap_fpga_irq = { + .name = "FPGA", + .irq_ack = fpga_ack_irq, + .irq_mask = fpga_mask_irq, + .irq_unmask = fpga_unmask_irq, +}; + +/* + * All of the FPGA interrupt request inputs except for the touchscreen are + * edge-sensitive; the touchscreen is level-sensitive. The edge-sensitive + * interrupts are acknowledged as a side-effect of reading the interrupt + * status register from the FPGA. The edge-sensitive interrupt inputs + * cause a problem with level interrupt requests, such as Ethernet. The + * problem occurs when a level interrupt request is asserted while its + * interrupt input is masked in the FPGA, which results in a missed + * interrupt. + * + * In an attempt to workaround the problem with missed interrupts, the + * mask_ack routine for all of the FPGA interrupts has been changed from + * fpga_mask_ack_irq() to fpga_ack_irq() so that the specific FPGA interrupt + * being serviced is left unmasked. We can do this because the FPGA cascade + * interrupt is run with all interrupts masked. + * + * Limited testing indicates that this workaround appears to be effective + * for the smc9194 Ethernet driver used on the Innovator. It should work + * on other FPGA interrupts as well, but any drivers that explicitly mask + * interrupts at the interrupt controller via disable_irq/enable_irq + * could pose a problem. + */ +void omap1510_fpga_init_irq(void) +{ + int i, res; + + __raw_writeb(0, OMAP1510_FPGA_IMR_LO); + __raw_writeb(0, OMAP1510_FPGA_IMR_HI); + __raw_writeb(0, INNOVATOR_FPGA_IMR2); + + for (i = OMAP_FPGA_IRQ_BASE; i < OMAP_FPGA_IRQ_END; i++) { + + if (i == OMAP1510_INT_FPGA_TS) { + /* + * The touchscreen interrupt is level-sensitive, so + * we'll use the regular mask_ack routine for it. + */ + irq_set_chip(i, &omap_fpga_irq_ack); + } + else { + /* + * All FPGA interrupts except the touchscreen are + * edge-sensitive, so we won't mask them. + */ + irq_set_chip(i, &omap_fpga_irq); + } + + irq_set_handler(i, handle_edge_irq); + irq_clear_status_flags(i, IRQ_NOREQUEST); + } + + /* + * The FPGA interrupt line is connected to GPIO13. Claim this pin for + * the ARM. + * + * NOTE: For general GPIO/MPUIO access and interrupts, please see + * gpio.[ch] + */ + res = gpio_request(13, "FPGA irq"); + if (res) { + pr_err("%s failed to get gpio\n", __func__); + return; + } + gpio_direction_input(13); + irq_set_irq_type(gpio_to_irq(13), IRQ_TYPE_EDGE_RISING); + irq_set_chained_handler(OMAP1510_INT_FPGA, innovator_fpga_IRQ_demux); +} |