[PATCH 2/2] vfio, platform: add QTI HIDMA reset driver

Sinan Kaya
2016-03-08T15:34:05Z

In situations where the userspace driver is stopped abnormally and the
VFIO platform device is released, the assigned HW device currently is
left running. As a consequence the HW device might continue issuing IRQs
and performing DMA accesses.

This patch is implementing a reset driver for HIDMA platform driver.
This gets called by the VFIO platform reset interface.

Reviewed-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
drivers/vfio/platform/reset/Kconfig | 9 ++
drivers/vfio/platform/reset/Makefile | 2 +
.../vfio/platform/reset/vfio_platform_qcomhidma.c | 101 +++++++++++++++++++++
3 files changed, 112 insertions(+)
create mode 100644 drivers/vfio/platform/reset/vfio_platform_qcomhidma.c

diff --git a/drivers/vfio/platform/reset/Kconfig b/drivers/vfio/platform/reset/Kconfig
index 70cccc5..d02b3b5 100644
--- a/drivers/vfio/platform/reset/Kconfig
+++ b/drivers/vfio/platform/reset/Kconfig
@@ -13,3 +13,12 @@ config VFIO_PLATFORM_AMDXGBE_RESET
Enables the VFIO platform driver to handle reset for AMD XGBE

If you don't know what to do here, say N.
+
+config VFIO_PLATFORM_QCOMHIDMA_RESET
+ tristate "VFIO support for Qualcomm Technologies HIDMA reset"
+ depends on VFIO_PLATFORM
+ help
+ Enables the VFIO platform driver to handle reset for Qualcomm Technologies
+ HIDMA Channel.
+
+ If you don't know what to do here, say N.
diff --git a/drivers/vfio/platform/reset/Makefile b/drivers/vfio/platform/reset/Makefile
index 93f4e23..ec7748a 100644
--- a/drivers/vfio/platform/reset/Makefile
+++ b/drivers/vfio/platform/reset/Makefile
@@ -1,7 +1,9 @@
vfio-platform-calxedaxgmac-y := vfio_platform_calxedaxgmac.o
vfio-platform-amdxgbe-y := vfio_platform_amdxgbe.o
+vfio-platform-qcomhidma-y := vfio_platform_qcomhidma.o

ccflags-y += -Idrivers/vfio/platform

obj-$(CONFIG_VFIO_PLATFORM_CALXEDAXGMAC_RESET) += vfio-platform-calxedaxgmac.o
+obj-$(CONFIG_VFIO_PLATFORM_QCOMHIDMA_RESET) += vfio-platform-qcomhidma.o
obj-$(CONFIG_VFIO_PLATFORM_AMDXGBE_RESET) += vfio-platform-amdxgbe.o
diff --git a/drivers/vfio/platform/reset/vfio_platform_qcomhidma.c b/drivers/vfio/platform/reset/vfio_platform_qcomhidma.c
new file mode 100644
index 0000000..103d481
--- /dev/null
+++ b/drivers/vfio/platform/reset/vfio_platform_qcomhidma.c
@@ -0,0 +1,101 @@
+/*
+ * Qualcomm Technologies HIDMA VFIO Reset Driver
+ *
+ * Copyright (c) 2016, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/device.h>
+#include <linux/iopoll.h>
+
+#include "vfio_platform_private.h"
+
+#define TRCA_CTRLSTS_OFFSET 0x000
+#define EVCA_CTRLSTS_OFFSET 0x000
+
+#define CH_CONTROL_MASK GENMASK(7, 0)
+#define CH_STATE_MASK GENMASK(7, 0)
+#define CH_STATE_BIT_POS 0x8
+
+#define HIDMA_CH_STATE(val) \
+ ((val >> CH_STATE_BIT_POS) & CH_STATE_MASK)
+
+#define EVCA_IRQ_EN_OFFSET 0x110
+
+#define CH_RESET 9
+#define CH_DISABLED 0
+
+int vfio_platform_qcomhidma_reset(struct vfio_platform_device *vdev)
+{
+ struct vfio_platform_region *trreg;
+ struct vfio_platform_region *evreg;
+ u32 val;
+ int ret;
+
+ if (vdev->num_regions != 2)
+ return -ENODEV;
+
+ trreg = &vdev->regions[0];
+ if (!trreg->ioaddr) {
+ trreg->ioaddr =
+ ioremap_nocache(trreg->addr, trreg->size);
+ if (!trreg->ioaddr)
+ return -ENOMEM;
+ }
+
+ evreg = &vdev->regions[1];
+ if (!evreg->ioaddr) {
+ evreg->ioaddr =
+ ioremap_nocache(evreg->addr, evreg->size);
+ if (!evreg->ioaddr)
+ return -ENOMEM;
+ }
+
+ /* disable IRQ */
+ writel(0, evreg->ioaddr + EVCA_IRQ_EN_OFFSET);
+
+ /* reset both transfer and event channels */
+ val = readl(trreg->ioaddr + TRCA_CTRLSTS_OFFSET);
+ val &= ~(CH_CONTROL_MASK << 16);
+ val |= CH_RESET << 16;
+ writel(val, trreg->ioaddr + TRCA_CTRLSTS_OFFSET);
+
+ ret = readl_poll_timeout(trreg->ioaddr + TRCA_CTRLSTS_OFFSET, val,
+ HIDMA_CH_STATE(val) == CH_DISABLED, 1000,
+ 10000);
+ if (ret)
+ return ret;
+
+ val = readl(evreg->ioaddr + EVCA_CTRLSTS_OFFSET);
+ val &= ~(CH_CONTROL_MASK << 16);
+ val |= CH_RESET << 16;
+ writel(val, evreg->ioaddr + EVCA_CTRLSTS_OFFSET);
+
+ ret = readl_poll_timeout(evreg->ioaddr + EVCA_CTRLSTS_OFFSET, val,
+ HIDMA_CH_STATE(val) == CH_DISABLED, 1000,
+ 10000);
+ if (ret)
+ return ret;
+
+ pr_info("HIDMA channel reset\n");
+ return 0;
+}
+module_vfio_reset_handler("qcom,hidma-1.0", "QCOM8061",
+ vfio_platform_qcomhidma_reset);
+VFIO_PLATFORM_MODULE_ALIAS("qcom,hidma-1.0");
+VFIO_PLATFORM_MODULE_ALIAS("QCOM8061");
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Reset support for Qualcomm Technologies HIDMA device");
--
1.8.2.1