linux/arch/arm/mach-pxa/pxa_cplds_irqs.c

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/*
* Intel Reference Systems cplds
*
* Copyright (C) 2014 Robert Jarzmik
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* Cplds motherboard driver, supporting lubbock and mainstone SoC board.
*/
#include <linux/bitops.h>
#include <linux/gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/mfd/core.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#define FPGA_IRQ_MASK_EN 0x0
#define FPGA_IRQ_SET_CLR 0x10
#define CPLDS_NB_IRQ 32
struct cplds {
void __iomem *base;
int irq;
unsigned int irq_mask;
struct gpio_desc *gpio0;
struct irq_domain *irqdomain;
};
static irqreturn_t cplds_irq_handler(int in_irq, void *d)
{
struct cplds *fpga = d;
unsigned long pending;
unsigned int bit;
ARM: pxa: pxa_cplds: fix interrupt handling Since its initial commit, the driver is buggy for multiple interrupts handling. The translation from the former lubbock.c file was not complete, and might stall all interrupt handling when multiple interrupts occur. This is especially true when inside the interrupt handler and if a new interrupt comes and is not handled, leaving the output line still held, and not creating a transition as the GPIO block behind would expect to trigger another cplds_irq_handler() call. For the record, the hardware is working as follows. The interrupt mechanism relies on : - one status register - one mask register Let's suppose the input irq lines are called : - i_sa1111 - i_lan91x - i_mmc_cd Let's suppose the status register for each irq line is called : - status_sa1111 - status_lan91x - status_mmc_cd Let's suppose the interrupt mask for each irq line is called : - irqen_sa1111 - irqen_lan91x - irqen_mmc_cd Let's suppose the output irq line, connected to GPIO0 is called : - o_gpio0 The behavior is as follows : - o_gpio0 = not((status_sa1111 & irqen_sa1111) | (status_lan91x & irqen_lan91x) | (status_mmc_cd & irqen_mmc_cd)) => this is a N-to-1 NOR gate and multiple AND gates - irqen_* is exactly as programmed by a write to the FPGA - status_* behavior is governed by a bi-stable D flip-flop => on next FPGA clock : - if i_xxx is high, status_xxx becomes 1 - if i_xxx is low, status_xxx remains as it is - if software sets status_xxx to 0, the D flip-flop is reset => status_xxx becomes 0 => on next FPGA clock cycle, if i_xxx is high, status_xxx becomes 1 again Fixes: fc9e38c0f4d3 ("ARM: pxa: lubbock: use new pxa_cplds driver") Reported-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
2016-09-04 18:59:45 +00:00
do {
pending = readl(fpga->base + FPGA_IRQ_SET_CLR) & fpga->irq_mask;
for_each_set_bit(bit, &pending, CPLDS_NB_IRQ) {
generic_handle_irq(irq_find_mapping(fpga->irqdomain,
bit));
}
} while (pending);
return IRQ_HANDLED;
}
ARM: pxa: pxa_cplds: fix interrupt handling Since its initial commit, the driver is buggy for multiple interrupts handling. The translation from the former lubbock.c file was not complete, and might stall all interrupt handling when multiple interrupts occur. This is especially true when inside the interrupt handler and if a new interrupt comes and is not handled, leaving the output line still held, and not creating a transition as the GPIO block behind would expect to trigger another cplds_irq_handler() call. For the record, the hardware is working as follows. The interrupt mechanism relies on : - one status register - one mask register Let's suppose the input irq lines are called : - i_sa1111 - i_lan91x - i_mmc_cd Let's suppose the status register for each irq line is called : - status_sa1111 - status_lan91x - status_mmc_cd Let's suppose the interrupt mask for each irq line is called : - irqen_sa1111 - irqen_lan91x - irqen_mmc_cd Let's suppose the output irq line, connected to GPIO0 is called : - o_gpio0 The behavior is as follows : - o_gpio0 = not((status_sa1111 & irqen_sa1111) | (status_lan91x & irqen_lan91x) | (status_mmc_cd & irqen_mmc_cd)) => this is a N-to-1 NOR gate and multiple AND gates - irqen_* is exactly as programmed by a write to the FPGA - status_* behavior is governed by a bi-stable D flip-flop => on next FPGA clock : - if i_xxx is high, status_xxx becomes 1 - if i_xxx is low, status_xxx remains as it is - if software sets status_xxx to 0, the D flip-flop is reset => status_xxx becomes 0 => on next FPGA clock cycle, if i_xxx is high, status_xxx becomes 1 again Fixes: fc9e38c0f4d3 ("ARM: pxa: lubbock: use new pxa_cplds driver") Reported-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
2016-09-04 18:59:45 +00:00
static void cplds_irq_mask(struct irq_data *d)
{
struct cplds *fpga = irq_data_get_irq_chip_data(d);
unsigned int cplds_irq = irqd_to_hwirq(d);
ARM: pxa: pxa_cplds: fix interrupt handling Since its initial commit, the driver is buggy for multiple interrupts handling. The translation from the former lubbock.c file was not complete, and might stall all interrupt handling when multiple interrupts occur. This is especially true when inside the interrupt handler and if a new interrupt comes and is not handled, leaving the output line still held, and not creating a transition as the GPIO block behind would expect to trigger another cplds_irq_handler() call. For the record, the hardware is working as follows. The interrupt mechanism relies on : - one status register - one mask register Let's suppose the input irq lines are called : - i_sa1111 - i_lan91x - i_mmc_cd Let's suppose the status register for each irq line is called : - status_sa1111 - status_lan91x - status_mmc_cd Let's suppose the interrupt mask for each irq line is called : - irqen_sa1111 - irqen_lan91x - irqen_mmc_cd Let's suppose the output irq line, connected to GPIO0 is called : - o_gpio0 The behavior is as follows : - o_gpio0 = not((status_sa1111 & irqen_sa1111) | (status_lan91x & irqen_lan91x) | (status_mmc_cd & irqen_mmc_cd)) => this is a N-to-1 NOR gate and multiple AND gates - irqen_* is exactly as programmed by a write to the FPGA - status_* behavior is governed by a bi-stable D flip-flop => on next FPGA clock : - if i_xxx is high, status_xxx becomes 1 - if i_xxx is low, status_xxx remains as it is - if software sets status_xxx to 0, the D flip-flop is reset => status_xxx becomes 0 => on next FPGA clock cycle, if i_xxx is high, status_xxx becomes 1 again Fixes: fc9e38c0f4d3 ("ARM: pxa: lubbock: use new pxa_cplds driver") Reported-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
2016-09-04 18:59:45 +00:00
unsigned int bit = BIT(cplds_irq);
fpga->irq_mask &= ~bit;
writel(fpga->irq_mask, fpga->base + FPGA_IRQ_MASK_EN);
}
static void cplds_irq_unmask(struct irq_data *d)
{
struct cplds *fpga = irq_data_get_irq_chip_data(d);
unsigned int cplds_irq = irqd_to_hwirq(d);
ARM: pxa: pxa_cplds: fix interrupt handling Since its initial commit, the driver is buggy for multiple interrupts handling. The translation from the former lubbock.c file was not complete, and might stall all interrupt handling when multiple interrupts occur. This is especially true when inside the interrupt handler and if a new interrupt comes and is not handled, leaving the output line still held, and not creating a transition as the GPIO block behind would expect to trigger another cplds_irq_handler() call. For the record, the hardware is working as follows. The interrupt mechanism relies on : - one status register - one mask register Let's suppose the input irq lines are called : - i_sa1111 - i_lan91x - i_mmc_cd Let's suppose the status register for each irq line is called : - status_sa1111 - status_lan91x - status_mmc_cd Let's suppose the interrupt mask for each irq line is called : - irqen_sa1111 - irqen_lan91x - irqen_mmc_cd Let's suppose the output irq line, connected to GPIO0 is called : - o_gpio0 The behavior is as follows : - o_gpio0 = not((status_sa1111 & irqen_sa1111) | (status_lan91x & irqen_lan91x) | (status_mmc_cd & irqen_mmc_cd)) => this is a N-to-1 NOR gate and multiple AND gates - irqen_* is exactly as programmed by a write to the FPGA - status_* behavior is governed by a bi-stable D flip-flop => on next FPGA clock : - if i_xxx is high, status_xxx becomes 1 - if i_xxx is low, status_xxx remains as it is - if software sets status_xxx to 0, the D flip-flop is reset => status_xxx becomes 0 => on next FPGA clock cycle, if i_xxx is high, status_xxx becomes 1 again Fixes: fc9e38c0f4d3 ("ARM: pxa: lubbock: use new pxa_cplds driver") Reported-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
2016-09-04 18:59:45 +00:00
unsigned int set, bit = BIT(cplds_irq);
set = readl(fpga->base + FPGA_IRQ_SET_CLR);
writel(set & ~bit, fpga->base + FPGA_IRQ_SET_CLR);
fpga->irq_mask |= bit;
writel(fpga->irq_mask, fpga->base + FPGA_IRQ_MASK_EN);
}
static struct irq_chip cplds_irq_chip = {
.name = "pxa_cplds",
ARM: pxa: pxa_cplds: fix interrupt handling Since its initial commit, the driver is buggy for multiple interrupts handling. The translation from the former lubbock.c file was not complete, and might stall all interrupt handling when multiple interrupts occur. This is especially true when inside the interrupt handler and if a new interrupt comes and is not handled, leaving the output line still held, and not creating a transition as the GPIO block behind would expect to trigger another cplds_irq_handler() call. For the record, the hardware is working as follows. The interrupt mechanism relies on : - one status register - one mask register Let's suppose the input irq lines are called : - i_sa1111 - i_lan91x - i_mmc_cd Let's suppose the status register for each irq line is called : - status_sa1111 - status_lan91x - status_mmc_cd Let's suppose the interrupt mask for each irq line is called : - irqen_sa1111 - irqen_lan91x - irqen_mmc_cd Let's suppose the output irq line, connected to GPIO0 is called : - o_gpio0 The behavior is as follows : - o_gpio0 = not((status_sa1111 & irqen_sa1111) | (status_lan91x & irqen_lan91x) | (status_mmc_cd & irqen_mmc_cd)) => this is a N-to-1 NOR gate and multiple AND gates - irqen_* is exactly as programmed by a write to the FPGA - status_* behavior is governed by a bi-stable D flip-flop => on next FPGA clock : - if i_xxx is high, status_xxx becomes 1 - if i_xxx is low, status_xxx remains as it is - if software sets status_xxx to 0, the D flip-flop is reset => status_xxx becomes 0 => on next FPGA clock cycle, if i_xxx is high, status_xxx becomes 1 again Fixes: fc9e38c0f4d3 ("ARM: pxa: lubbock: use new pxa_cplds driver") Reported-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
2016-09-04 18:59:45 +00:00
.irq_ack = cplds_irq_mask,
.irq_mask = cplds_irq_mask,
.irq_unmask = cplds_irq_unmask,
.flags = IRQCHIP_MASK_ON_SUSPEND | IRQCHIP_SKIP_SET_WAKE,
};
static int cplds_irq_domain_map(struct irq_domain *d, unsigned int irq,
irq_hw_number_t hwirq)
{
struct cplds *fpga = d->host_data;
irq_set_chip_and_handler(irq, &cplds_irq_chip, handle_level_irq);
irq_set_chip_data(irq, fpga);
return 0;
}
static const struct irq_domain_ops cplds_irq_domain_ops = {
.xlate = irq_domain_xlate_twocell,
.map = cplds_irq_domain_map,
};
static int cplds_resume(struct platform_device *pdev)
{
struct cplds *fpga = platform_get_drvdata(pdev);
writel(fpga->irq_mask, fpga->base + FPGA_IRQ_MASK_EN);
return 0;
}
static int cplds_probe(struct platform_device *pdev)
{
struct resource *res;
struct cplds *fpga;
int ret;
int base_irq;
unsigned long irqflags = 0;
fpga = devm_kzalloc(&pdev->dev, sizeof(*fpga), GFP_KERNEL);
if (!fpga)
return -ENOMEM;
fpga->irq = platform_get_irq(pdev, 0);
if (fpga->irq <= 0)
return fpga->irq;
base_irq = platform_get_irq(pdev, 1);
if (base_irq < 0)
base_irq = 0;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
fpga->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(fpga->base))
return PTR_ERR(fpga->base);
platform_set_drvdata(pdev, fpga);
writel(fpga->irq_mask, fpga->base + FPGA_IRQ_MASK_EN);
writel(0, fpga->base + FPGA_IRQ_SET_CLR);
irqflags = irq_get_trigger_type(fpga->irq);
ret = devm_request_irq(&pdev->dev, fpga->irq, cplds_irq_handler,
irqflags, dev_name(&pdev->dev), fpga);
if (ret == -ENOSYS)
return -EPROBE_DEFER;
if (ret) {
dev_err(&pdev->dev, "couldn't request main irq%d: %d\n",
fpga->irq, ret);
return ret;
}
irq_set_irq_wake(fpga->irq, 1);
fpga->irqdomain = irq_domain_add_linear(pdev->dev.of_node,
CPLDS_NB_IRQ,
&cplds_irq_domain_ops, fpga);
if (!fpga->irqdomain)
return -ENODEV;
if (base_irq) {
ret = irq_create_strict_mappings(fpga->irqdomain, base_irq, 0,
CPLDS_NB_IRQ);
if (ret) {
dev_err(&pdev->dev, "couldn't create the irq mapping %d..%d\n",
base_irq, base_irq + CPLDS_NB_IRQ);
return ret;
}
}
return 0;
}
static int cplds_remove(struct platform_device *pdev)
{
struct cplds *fpga = platform_get_drvdata(pdev);
irq_set_chip_and_handler(fpga->irq, NULL, NULL);
return 0;
}
static const struct of_device_id cplds_id_table[] = {
{ .compatible = "intel,lubbock-cplds-irqs", },
{ .compatible = "intel,mainstone-cplds-irqs", },
{ }
};
MODULE_DEVICE_TABLE(of, cplds_id_table);
static struct platform_driver cplds_driver = {
.driver = {
.name = "pxa_cplds_irqs",
.of_match_table = of_match_ptr(cplds_id_table),
},
.probe = cplds_probe,
.remove = cplds_remove,
.resume = cplds_resume,
};
module_platform_driver(cplds_driver);
MODULE_DESCRIPTION("PXA Cplds interrupts driver");
MODULE_AUTHOR("Robert Jarzmik <robert.jarzmik@free.fr>");
MODULE_LICENSE("GPL");