VFIO: platform: reset: AMD xgbe reset module

This patch introduces a module that registers and implements a low-level
reset function for the AMD XGBE device.

it performs the following actions:
- reset the PHY
- disable auto-negotiation
- disable & clear auto-negotiation IRQ
- soft-reset the MAC

Those tiny pieces of code are inherited from the native xgbe driver.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

3 files changed, 137 insertions, 0 deletions

diff --git a/drivers/vfio/platform/reset/Kconfig b/drivers/vfio/platform/reset/Kconfig
index 746b96b0003b..70cccc582bee 100644
--- a/drivers/vfio/platform/reset/Kconfig
+++ b/drivers/vfio/platform/reset/Kconfig
@@ -5,3 +5,11 @@ config VFIO_PLATFORM_CALXEDAXGMAC_RESET
           Enables the VFIO platform driver to handle reset for Calxeda xgmac
 
           If you don't know what to do here, say N.
+
+config VFIO_PLATFORM_AMDXGBE_RESET
+        tristate "VFIO support for AMD XGBE reset"
+        depends on VFIO_PLATFORM
+        help
+          Enables the VFIO platform driver to handle reset for AMD XGBE
+
+          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 2a486af9f8fa..93f4e232697b 100644
--- a/drivers/vfio/platform/reset/Makefile
+++ b/drivers/vfio/platform/reset/Makefile
@@ -1,5 +1,7 @@
 vfio-platform-calxedaxgmac-y := vfio_platform_calxedaxgmac.o
+vfio-platform-amdxgbe-y := vfio_platform_amdxgbe.o
 
 ccflags-y += -Idrivers/vfio/platform
 
 obj-$(CONFIG_VFIO_PLATFORM_CALXEDAXGMAC_RESET) += vfio-platform-calxedaxgmac.o
+obj-$(CONFIG_VFIO_PLATFORM_AMDXGBE_RESET) += vfio-platform-amdxgbe.o
diff --git a/drivers/vfio/platform/reset/vfio_platform_amdxgbe.c b/drivers/vfio/platform/reset/vfio_platform_amdxgbe.c
new file mode 100644
index 000000000000..da5356f48d0b
--- /dev/null
+++ b/drivers/vfio/platform/reset/vfio_platform_amdxgbe.c
@@ -0,0 +1,127 @@
+/*
+ * VFIO platform driver specialized for AMD xgbe reset
+ * reset code is inherited from AMD xgbe native driver
+ *
+ * Copyright (c) 2015 Linaro Ltd.
+ *              www.linaro.org
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <uapi/linux/mdio.h>
+#include <linux/delay.h>
+
+#include "vfio_platform_private.h"
+
+#define DMA_MR                  0x3000
+#define MAC_VR                  0x0110
+#define DMA_ISR                 0x3008
+#define MAC_ISR                 0x00b0
+#define PCS_MMD_SELECT          0xff
+#define MDIO_AN_INT             0x8002
+#define MDIO_AN_INTMASK         0x8001
+
+static unsigned int xmdio_read(void *ioaddr, unsigned int mmd,
+                               unsigned int reg)
+{
+        unsigned int mmd_address, value;
+
+        mmd_address = (mmd << 16) | ((reg) & 0xffff);
+        iowrite32(mmd_address >> 8, ioaddr + (PCS_MMD_SELECT << 2));
+        value = ioread32(ioaddr + ((mmd_address & 0xff) << 2));
+        return value;
+}
+
+static void xmdio_write(void *ioaddr, unsigned int mmd,
+                        unsigned int reg, unsigned int value)
+{
+        unsigned int mmd_address;
+
+        mmd_address = (mmd << 16) | ((reg) & 0xffff);
+        iowrite32(mmd_address >> 8, ioaddr + (PCS_MMD_SELECT << 2));
+        iowrite32(value, ioaddr + ((mmd_address & 0xff) << 2));
+}
+
+int vfio_platform_amdxgbe_reset(struct vfio_platform_device *vdev)
+{
+        struct vfio_platform_region *xgmac_regs = &vdev->regions[0];
+        struct vfio_platform_region *xpcs_regs = &vdev->regions[1];
+        u32 dma_mr_value, pcs_value, value;
+        unsigned int count;
+
+        if (!xgmac_regs->ioaddr) {
+                xgmac_regs->ioaddr =
+                        ioremap_nocache(xgmac_regs->addr, xgmac_regs->size);
+                if (!xgmac_regs->ioaddr)
+                        return -ENOMEM;
+        }
+        if (!xpcs_regs->ioaddr) {
+                xpcs_regs->ioaddr =
+                        ioremap_nocache(xpcs_regs->addr, xpcs_regs->size);
+                if (!xpcs_regs->ioaddr)
+                        return -ENOMEM;
+        }
+
+        /* reset the PHY through MDIO*/
+        pcs_value = xmdio_read(xpcs_regs->ioaddr, MDIO_MMD_PCS, MDIO_CTRL1);
+        pcs_value |= MDIO_CTRL1_RESET;
+        xmdio_write(xpcs_regs->ioaddr, MDIO_MMD_PCS, MDIO_CTRL1, pcs_value);
+
+        count = 50;
+        do {
+                msleep(20);
+                pcs_value = xmdio_read(xpcs_regs->ioaddr, MDIO_MMD_PCS,
+                                        MDIO_CTRL1);
+        } while ((pcs_value & MDIO_CTRL1_RESET) && --count);
+
+        if (pcs_value & MDIO_CTRL1_RESET)
+                pr_warn("%s XGBE PHY reset timeout\n", __func__);
+
+        /* disable auto-negotiation */
+        value = xmdio_read(xpcs_regs->ioaddr, MDIO_MMD_AN, MDIO_CTRL1);
+        value &= ~MDIO_AN_CTRL1_ENABLE;
+        xmdio_write(xpcs_regs->ioaddr, MDIO_MMD_AN, MDIO_CTRL1, value);
+
+        /* disable AN IRQ */
+        xmdio_write(xpcs_regs->ioaddr, MDIO_MMD_AN, MDIO_AN_INTMASK, 0);
+
+        /* clear AN IRQ */
+        xmdio_write(xpcs_regs->ioaddr, MDIO_MMD_AN, MDIO_AN_INT, 0);
+
+        /* MAC software reset */
+        dma_mr_value = ioread32(xgmac_regs->ioaddr + DMA_MR);
+        dma_mr_value |= 0x1;
+        iowrite32(dma_mr_value, xgmac_regs->ioaddr + DMA_MR);
+
+        usleep_range(10, 15);
+
+        count = 2000;
+        while (count-- && (ioread32(xgmac_regs->ioaddr + DMA_MR) & 1))
+                usleep_range(500, 600);
+
+        if (!count)
+                pr_warn("%s MAC SW reset failed\n", __func__);
+
+        return 0;
+}
+
+module_vfio_reset_handler("amd,xgbe-seattle-v1a", vfio_platform_amdxgbe_reset);
+
+MODULE_VERSION("0.1");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Eric Auger <eric.auger@linaro.org>");
+MODULE_DESCRIPTION("Reset support for AMD xgbe vfio platform device");