[Xen-devel] [PATCH 06/13] Xen: ARM: Add support for mapping amba device mmio

On 2015/11/17 22:40, Konrad Rzeszutek Wilk wrote:

On Tue, Nov 17, 2015 at 05:57:04PM +0800, shannon.zhao at linaro.org wrote:

quoted

From: Shannon Zhao <redacted>

Add a bus_notifier for AMBA bus device in order to map the device
mmio regions when DOM0 booting with ACPI.

Signed-off-by: Shannon Zhao <redacted>
---
 drivers/xen/Makefile |  1 +
 drivers/xen/amba.c   | 99 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 100 insertions(+)
 create mode 100644 drivers/xen/amba.c

diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index 2f867e7..139bd0b 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile

@@ -12,6 +12,7 @@ CFLAGS_features.o			:= $(nostackp)
 CFLAGS_efi.o				+= -fshort-wchar
 
 dom0-$(CONFIG_ARM64) += platform.o
+dom0-$(CONFIG_ARM_AMBA) += amba.o
 dom0-$(CONFIG_PCI) += pci.o
 dom0-$(CONFIG_USB_SUPPORT) += dbgp.o
 dom0-$(CONFIG_XEN_ACPI) += acpi.o $(xen-pad-y)

diff --git a/drivers/xen/amba.c b/drivers/xen/amba.c
new file mode 100644
index 0000000..e491c8e
--- /dev/null
+++ b/drivers/xen/amba.c

@@ -0,0 +1,99 @@
+/*
+ * Copyright (c) 2015, Linaro Limited.
+ *
+ * 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, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * Author: Shannon Zhao <shannon.zhao@linaro.org>
+ */
+
+#include <linux/amba/bus.h>
+#include <linux/acpi.h>
+#include <xen/xen.h>
+#include <xen/interface/memory.h>
+#include <asm/xen/hypervisor.h>
+#include <asm/xen/hypercall.h>
+
+static int xen_map_amba_device_mmio(struct amba_device *adev)
+{
+	int rc = 0;
+	struct resource *r = &adev->res;
+
+	if (resource_type(r) == IORESOURCE_MEM)

This is like the 'xen_map_platform_device_mmio' code. Why don't you call
that? Or at least make the 'xen_map_platform_device_mmio' internal parts be
visible to both of these functions.

Ok, will do.

quoted

+	{
+		int j;
+		int nr = DIV_ROUND_UP(resource_size(r), PAGE_SIZE);
+		xen_pfn_t *gpfns = kmalloc(sizeof(xen_pfn_t) * nr, GFP_KERNEL);
+		xen_ulong_t *idxs = kmalloc(sizeof(xen_ulong_t) * nr,
+					    GFP_KERNEL);
+		int *errs = kmalloc(sizeof(int) * nr, GFP_KERNEL);
+		struct xen_add_to_physmap_range xatp;
+
+		for (j = 0; j < nr; j++) {
+			gpfns[j] = (r->start >> PAGE_SHIFT) + j;
+			idxs[j] = (r->start >> PAGE_SHIFT) + j;
+			errs[j] = 0;
+		}
+
+		xatp.domid = DOMID_SELF;
+		xatp.size = nr;
+		xatp.space = XENMAPSPACE_dev_mmio;
+
+		set_xen_guest_handle(xatp.gpfns, gpfns);
+		set_xen_guest_handle(xatp.idxs, idxs);
+		set_xen_guest_handle(xatp.errs, errs);
+
+		rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp);
+
+		kfree(gpfns);
+		kfree(idxs);
+		kfree(errs);
+		if (rc != 0)
+			return rc;
+	}
+
+	return rc;
+}
+
+static int xen_amba_notifier(struct notifier_block *nb,
+			     unsigned long action, void *data)
+{
+	struct amba_device *adev = to_amba_device(data);
+	int r = 0;
+
+	if (!acpi_disabled && (action == BUS_NOTIFY_ADD_DEVICE))
+		r = xen_map_amba_device_mmio(adev);
+

What about the removal of a bus device? No need to handle that?

I have thought about removal before. I think there is little(or no)
chance for AMBA and platform bus devices to be removed. It's not like
the PCI devices which will be hot-unplug.
Maybe I'm not right. If so, it's fine to add a case to handle the removal.

Thanks,
-- 
Shannon