This commit adds a simple driver for the Marvell GICP, a hardware unit
that converts memory writes into GIC SPI interrupts. The driver provides
a number of functions to the ICU driver to allocate GICP interrupts, and
get the physical addresses that the ICUs should write to to set/clear
interrupts.

Signed-off-by: Thomas Petazzoni <thomas.petazz...@free-electrons.com>
---
 drivers/irqchip/Kconfig          |   3 +
 drivers/irqchip/Makefile         |   1 +
 drivers/irqchip/irq-mvebu-gicp.c | 170 +++++++++++++++++++++++++++++++++++++++
 drivers/irqchip/irq-mvebu-gicp.h |  15 ++++
 4 files changed, 189 insertions(+)
 create mode 100644 drivers/irqchip/irq-mvebu-gicp.c
 create mode 100644 drivers/irqchip/irq-mvebu-gicp.h

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 478f8ac..e527ee5 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -268,6 +268,9 @@ config IRQ_MXS
        select IRQ_DOMAIN
        select STMP_DEVICE
 
+config MVEBU_GICP
+       bool
+
 config MVEBU_ODMI
        bool
        select GENERIC_MSI_IRQ_DOMAIN
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index b64c59b..11eb858 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -69,6 +69,7 @@ obj-$(CONFIG_ARCH_SA1100)             += irq-sa11x0.o
 obj-$(CONFIG_INGENIC_IRQ)              += irq-ingenic.o
 obj-$(CONFIG_IMX_GPCV2)                        += irq-imx-gpcv2.o
 obj-$(CONFIG_PIC32_EVIC)               += irq-pic32-evic.o
+obj-$(CONFIG_MVEBU_GICP)               += irq-mvebu-gicp.o
 obj-$(CONFIG_MVEBU_ODMI)               += irq-mvebu-odmi.o
 obj-$(CONFIG_MVEBU_PIC)                        += irq-mvebu-pic.o
 obj-$(CONFIG_LS_SCFG_MSI)              += irq-ls-scfg-msi.o
diff --git a/drivers/irqchip/irq-mvebu-gicp.c b/drivers/irqchip/irq-mvebu-gicp.c
new file mode 100644
index 0000000..73c0117
--- /dev/null
+++ b/drivers/irqchip/irq-mvebu-gicp.c
@@ -0,0 +1,170 @@
+/*
+ * Copyright (C) 2017 Marvell
+ *
+ * Thomas Petazzoni <thomas.petazz...@free-electrons.com>
+ *
+ * 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/io.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+#include "irq-mvebu-gicp.h"
+
+#define GICP_SETSPI_NSR_OFFSET 0x0
+#define GICP_CLRSPI_NSR_OFFSET 0x8
+
+struct mvebu_gicp_spi_range {
+       unsigned int start;
+       unsigned int count;
+};
+
+struct mvebu_gicp {
+       struct mvebu_gicp_spi_range *spi_ranges;
+       unsigned int spi_ranges_cnt;
+       unsigned int spi_cnt;
+       unsigned long *spi_bitmap;
+       spinlock_t spi_lock;
+       struct resource *res;
+};
+
+int mvebu_gicp_alloc(struct mvebu_gicp *gicp)
+{
+       int idx;
+
+       spin_lock(&gicp->spi_lock);
+       idx = find_first_zero_bit(gicp->spi_bitmap, gicp->spi_cnt);
+       if (idx == gicp->spi_cnt) {
+               spin_unlock(&gicp->spi_lock);
+               return -ENOSPC;
+       }
+       set_bit(idx, gicp->spi_bitmap);
+       spin_unlock(&gicp->spi_lock);
+
+       return idx;
+}
+
+void mvebu_gicp_free(struct mvebu_gicp *gicp, int idx)
+{
+       spin_lock(&gicp->spi_lock);
+       clear_bit(idx, gicp->spi_bitmap);
+       spin_unlock(&gicp->spi_lock);
+}
+
+int mvebu_gicp_idx_to_spi(struct mvebu_gicp *gicp, int idx)
+{
+       int i;
+
+       for (i = 0; i < gicp->spi_ranges_cnt; i++) {
+               struct mvebu_gicp_spi_range *r = &gicp->spi_ranges[i];
+
+               if (idx < r->count)
+                       return r->start + idx;
+
+               idx -= r->count;
+       }
+
+       return -EINVAL;
+}
+
+int mvebu_gicp_spi_to_idx(struct mvebu_gicp *gicp, int spi)
+{
+       int i;
+       int idx = 0;
+
+       for (i = 0; i < gicp->spi_ranges_cnt; i++) {
+               struct mvebu_gicp_spi_range *r = &gicp->spi_ranges[i];
+
+               if (spi >= r->start && spi < (r->start + r->count))
+                       return idx + (spi - r->start);
+
+               idx += r->count;
+       }
+
+       return -EINVAL;
+}
+
+int mvebu_gicp_spi_count(struct mvebu_gicp *gicp)
+{
+       return gicp->spi_cnt;
+}
+
+phys_addr_t mvebu_gicp_setspi_phys_addr(struct mvebu_gicp *gicp)
+{
+       return gicp->res->start + GICP_SETSPI_NSR_OFFSET;
+}
+
+phys_addr_t mvebu_gicp_clrspi_phys_addr(struct mvebu_gicp *gicp)
+{
+       return gicp->res->start + GICP_CLRSPI_NSR_OFFSET;
+}
+
+static int mvebu_gicp_probe(struct platform_device *pdev)
+{
+       struct mvebu_gicp *gicp;
+       int ret, i;
+
+       gicp = devm_kzalloc(&pdev->dev, sizeof(*gicp), GFP_KERNEL);
+       if (!gicp)
+               return -ENOMEM;
+
+       gicp->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       if (!gicp->res)
+               return -ENODEV;
+
+       ret = of_property_count_u32_elems(pdev->dev.of_node,
+                                         "marvell,spi-ranges");
+       if (ret < 0)
+               return ret;
+
+       gicp->spi_ranges_cnt = ret / 2;
+
+       gicp->spi_ranges =
+               devm_kzalloc(&pdev->dev,
+                            gicp->spi_ranges_cnt *
+                            sizeof(struct mvebu_gicp_spi_range),
+                            GFP_KERNEL);
+       if (!gicp->spi_ranges)
+               return -ENOMEM;
+
+       for (i = 0; i < gicp->spi_ranges_cnt; i++) {
+               of_property_read_u32_index(pdev->dev.of_node,
+                                          "marvell,spi-ranges",
+                                          i * 2,
+                                          &gicp->spi_ranges[i].start);
+
+               of_property_read_u32_index(pdev->dev.of_node,
+                                          "marvell,spi-ranges",
+                                          i * 2 + 1,
+                                          &gicp->spi_ranges[i].count);
+
+               gicp->spi_cnt += gicp->spi_ranges[i].count;
+       }
+
+       gicp->spi_bitmap = devm_kzalloc(&pdev->dev,
+                                       BITS_TO_LONGS(gicp->spi_cnt),
+                                       GFP_KERNEL);
+       if (!gicp->spi_bitmap)
+               return -ENOMEM;
+
+       platform_set_drvdata(pdev, gicp);
+
+       return 0;
+}
+
+static const struct of_device_id mvebu_gicp_of_match[] = {
+       { .compatible = "marvell,ap806-gicp", },
+       {},
+};
+
+static struct platform_driver mvebu_gicp_driver = {
+       .probe  = mvebu_gicp_probe,
+       .driver = {
+               .name = "mvebu-gicp",
+               .of_match_table = mvebu_gicp_of_match,
+       },
+};
+builtin_platform_driver(mvebu_gicp_driver);
diff --git a/drivers/irqchip/irq-mvebu-gicp.h b/drivers/irqchip/irq-mvebu-gicp.h
new file mode 100644
index 0000000..7290166
--- /dev/null
+++ b/drivers/irqchip/irq-mvebu-gicp.h
@@ -0,0 +1,15 @@
+#ifndef __MVEBU_GICP_H__
+#define __MVEBU_GICP_H__
+
+struct mvebu_gicp;
+
+int mvebu_gicp_alloc(struct mvebu_gicp *gicp);
+void mvebu_gicp_free(struct mvebu_gicp *gicp, int idx);
+int mvebu_gicp_idx_to_spi(struct mvebu_gicp *gicp, int idx);
+int mvebu_gicp_spi_to_idx(struct mvebu_gicp *gicp, int spi);
+phys_addr_t mvebu_gicp_setspi_phys_addr(struct mvebu_gicp *gicp);
+phys_addr_t mvebu_gicp_clrspi_phys_addr(struct mvebu_gicp *gicp);
+int mvebu_gicp_spi_count(struct mvebu_gicp *gicp);
+
+#endif /* __MVEBU_GICP_H__ */
+
-- 
2.7.4

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