[PATCH v8 09/28] bus: mvebu-mbus: Add static window allocation to the DT binding
Ezequiel Garcia
ezequiel.garcia at free-electrons.com
Tue Jul 23 09:31:13 EDT 2013
This patch adds static window allocation to the device tree binding.
Each first-child of the mbus-compatible node, with a suitable 'ranges'
property, declaring an address translation, will trigger an address
decoding window allocation.
Signed-off-by: Ezequiel Garcia <ezequiel.garcia at free-electrons.com>
---
Changes from v7:
* Allow nodes with no ranges property
.../devicetree/bindings/bus/mvebu-mbus.txt | 253 +++++++++++++++++++++
drivers/bus/mvebu-mbus.c | 127 ++++++++++-
2 files changed, 379 insertions(+), 1 deletion(-)
create mode 100644 Documentation/devicetree/bindings/bus/mvebu-mbus.txt
diff --git a/Documentation/devicetree/bindings/bus/mvebu-mbus.txt b/Documentation/devicetree/bindings/bus/mvebu-mbus.txt
new file mode 100644
index 0000000..cce863f
--- /dev/null
+++ b/Documentation/devicetree/bindings/bus/mvebu-mbus.txt
@@ -0,0 +1,253 @@
+
+* Marvell MBus
+
+Required properties:
+
+- compatible: Should be set to one of the following:
+ marvell,armada370-mbus
+ marvell,armadaxp-mbus
+
+- address-cells: Must be '2'. The first cell for the MBus ID encoding,
+ the second cell for the address offset within the window.
+
+- size-cells: Must be '1'.
+
+- ranges: Must be set up to provide a proper translation for each child.
+ See the examples below.
+
+- controller: Contains a single phandle referring to the MBus controller
+ node. This allows to specify the node that contains the
+ registers that control the MBus, which is typically contained
+ within the internal register window (see below).
+
+* Marvell MBus controller
+
+Required properties:
+
+- compatible: Should be set to "marvell,mbus-controller".
+
+- reg: Device's register space.
+ Two entries are expected (see the examples below):
+ the first one controls the devices decoding window and
+ the second one controls the SDRAM decoding window.
+
+Example:
+
+ soc {
+ compatible = "marvell,armada370-mbus", "simple-bus";
+ #address-cells = <2>;
+ #size-cells = <1>;
+ controller = <&mbusc>;
+
+ internal-regs {
+ compatible = "simple-bus";
+
+ mbusc: mbus-controller at 20000 {
+ compatible = "marvell,mbus-controller";
+ reg = <0x20000 0x100>, <0x20180 0x20>;
+ };
+
+ /* more children ...*/
+ };
+ };
+
+** MBus address decoding window specification
+
+The MBus children address space is comprised of two cells: the first one for
+the window ID and the second one for the offset within the window.
+In order to allow to describe valid and non-valid window entries, the
+following encoding is used:
+
+ 0xSIAA0000 0x00oooooo
+
+Where:
+
+ S = 0x0 for a MBus valid window
+ S = 0xf for a non-valid window (see below)
+
+If S = 0x0, then:
+
+ I = 4-bit window target ID
+ AA = windpw attribute
+
+If S = 0xf, then:
+
+ I = don't care
+ AA = 1 for internal register
+
+Following the above encoding, for each ranges entry for a MBus valid window
+(S = 0x0), an address decoding window is allocated. On the other side,
+entries for translation that do not correspond to valid windows (S = 0xf)
+are skipped.
+
+ soc {
+ compatible = "marvell,armada370-mbus", "simple-bus";
+ #address-cells = <2>;
+ #size-cells = <1>;
+ controller = <&mbusc>;
+
+ ranges = <0xf0010000 0 0 0xd0000000 0x100000
+ 0x01e00000 0 0 0xfff00000 0x100000>;
+
+ bootrom {
+ compatible = "marvell,bootrom";
+ reg = <0x01e00000 0 0x100000>;
+ };
+
+ /* other children */
+ ...
+
+ internal-regs {
+ compatible = "simple-bus";
+ ranges = <0 0xf0010000 0 0x100000>;
+
+ mbusc: mbus-controller at 20000 {
+ compatible = "marvell,mbus-controller";
+ reg = <0x20000 0x100>, <0x20180 0x20>;
+ };
+
+ /* more children ...*/
+ };
+ };
+
+In the shown example, the translation entry in the 'ranges' property is what
+makes the MBus driver create a static decoding window for the corresponding
+given child device. Note that the binding does not require child nodes to be
+present. Of course, child nodes are needed to probe the devices.
+
+Since each window is identified by its target ID and attribute ID there's
+a special macro that can be use to simplify the translation entries:
+
+#define MBUS_ID(target,attributes) (((target) << 24) | ((attributes) << 16))
+
+Using this macro, the above example would be:
+
+ soc {
+ compatible = "marvell,armada370-mbus", "simple-bus";
+ #address-cells = <2>;
+ #size-cells = <1>;
+ controller = <&mbusc>;
+
+ ranges = < MBUS_ID(0xf0, 0x01) 0 0 0xd0000000 0x100000
+ MBUS_ID(0x01, 0xe0) 0 0 0xfff00000 0x100000>;
+
+ bootrom {
+ compatible = "marvell,bootrom";
+ reg = <MBUS_ID(0x01, 0xe0) 0 0x100000>;
+ };
+
+ /* other children */
+ ...
+
+ internal-regs {
+ compatible = "simple-bus";
+ #address-cells = <1>;
+ #size-cells = <1>;
+ ranges = <0 MBUS_ID(0xf0, 0x01) 0 0x100000>;
+
+ mbusc: mbus-controller at 20000 {
+ compatible = "marvell,mbus-controller";
+ reg = <0x20000 0x100>, <0x20180 0x20>;
+ };
+
+ /* other children */
+ ...
+ };
+ };
+
+
+** About the window base address
+
+Remember the MBus controller allows a great deal of flexibility for choosing
+the decoding window base address. When planning the device tree layout it's
+possible to choose any address as the base address, provided of course there's
+a region large enough available, and with the required alignment.
+
+Yet in other words: there's nothing preventing us from setting a base address
+of 0xf0000000, or 0xd0000000 for the NOR device shown above, if such region is
+unused.
+
+** Window allocation policy
+
+The mbus-node ranges property defines a set of mbus windows that are expected
+to be set by the operating system and that are guaranteed to be free of overlaps
+with one another or with the system memory ranges.
+
+Each entry in the property refers to exactly one window. If the operating system
+choses to use a different set of mbus windows, it must ensure that any address
+translations performed from downstream devices are adapted accordingly.
+
+The operating system may insert additional mbus windows that do not conflict
+with the ones listed in the ranges, e.g. for mapping PCIe devices.
+As a special case, the internal register window must be set up by the boot
+loader at the address listed in the ranges property, since access to that region
+is needed to set up the other windows.
+
+** Example
+
+See the example below, where a more complete device tree is shown:
+
+ soc {
+ compatible = "marvell,armadaxp-mbus", "simple-bus";
+ controller = <&mbusc>;
+
+ ranges = <MBUS_ID(0xf0, 0x01) 0 0 0xd0000000 0x100000 /* internal-regs */
+ MBUS_ID(0x01, 0x1d) 0 0 0xfff00000 0x100000
+ MBUS_ID(0x01, 0x2f) 0 0 0xf0000000 0x8000000>;
+
+ bootrom {
+ compatible = "marvell,bootrom";
+ reg = <MBUS_ID(0x01, 0x1d) 0 0x100000>;
+ };
+
+ devbus-bootcs {
+ status = "okay";
+ ranges = <0 MBUS_ID(0x01, 0x2f) 0 0x8000000>;
+
+ /* NOR */
+ nor {
+ compatible = "cfi-flash";
+ reg = <0 0x8000000>;
+ bank-width = <2>;
+ };
+ };
+
+ pcie-controller {
+ compatible = "marvell,armada-xp-pcie";
+ status = "okay";
+ device_type = "pci";
+
+ #address-cells = <3>;
+ #size-cells = <2>;
+
+ ranges =
+ <0x82000000 0 0x40000 MBUS_ID(0xf0, 0x01) 0x40000 0 0x00002000 /* Port 0.0 registers */
+ 0x82000000 0 0x42000 MBUS_ID(0xf0, 0x01) 0x42000 0 0x00002000 /* Port 2.0 registers */
+ 0x82000000 0 0x44000 MBUS_ID(0xf0, 0x01) 0x44000 0 0x00002000 /* Port 0.1 registers */
+ 0x82000000 0 0x48000 MBUS_ID(0xf0, 0x01) 0x48000 0 0x00002000 /* Port 0.2 registers */
+ 0x82000000 0 0x4c000 MBUS_ID(0xf0, 0x01) 0x4c000 0 0x00002000 /* Port 0.3 registers */
+ 0x82000800 0 0xe0000000 MBUS_ID(0x04, 0xe8) 0xe0000000 0 0x08000000 /* Port 0.0 MEM */
+ 0x81000800 0 0 MBUS_ID(0x04, 0xe0) 0xe8000000 0 0x00100000 /* Port 0.0 IO */>;
+
+
+ pcie at 1,0 {
+ /* Port 0, Lane 0 */
+ status = "okay";
+ };
+ };
+
+ internal-regs {
+ compatible = "simple-bus";
+ #address-cells = <1>;
+ #size-cells = <1>;
+ ranges = <0 MBUS_ID(0xf0, 0x01) 0 0x100000>;
+
+ mbusc: mbus-controller at 20000 {
+ reg = <0x20000 0x100>, <0x20180 0x20>;
+ };
+
+ interrupt-controller at 20000 {
+ reg = <0x20a00 0x2d0>, <0x21070 0x58>;
+ };
+ };
+ };
diff --git a/drivers/bus/mvebu-mbus.c b/drivers/bus/mvebu-mbus.c
index 44a07c4..78b8c04 100644
--- a/drivers/bus/mvebu-mbus.c
+++ b/drivers/bus/mvebu-mbus.c
@@ -902,6 +902,127 @@ int __init mvebu_mbus_init(const char *soc, phys_addr_t mbuswins_phys_base,
}
#ifdef CONFIG_OF
+/*
+ * The window IDs in the ranges DT property have the following format:
+ * - bits 28 to 31: MBus custom field
+ * - bits 24 to 27: window target ID
+ * - bits 16 to 23: window attribute ID
+ * - bits 0 to 15: unused
+ */
+#define CUSTOM(id) (((id) & 0xF0000000) >> 24)
+#define TARGET(id) (((id) & 0x0F000000) >> 24)
+#define ATTR(id) (((id) & 0x00FF0000) >> 16)
+
+static int __init mbus_dt_setup_win(struct mvebu_mbus_state *mbus,
+ u32 base, u32 size,
+ u8 target, u8 attr)
+{
+ const struct mvebu_mbus_mapping *map = mbus->soc->map;
+ const char *name;
+ int i;
+
+ /* Search for a suitable window in the existing mappings */
+ for (i = 0; map[i].name; i++)
+ if (map[i].target == target &&
+ map[i].attr == (attr & map[i].attrmask))
+ break;
+
+ name = map[i].name;
+ if (!name) {
+ pr_err("window 0x%x:0x%x is unknown, skipping\n",
+ target, attr);
+ return -EINVAL;
+ }
+
+ if (!mvebu_mbus_window_conflicts(mbus, base, size, target, attr)) {
+ pr_err("cannot add window '%s', conflicts with another window\n",
+ name);
+ return -EBUSY;
+ }
+
+ if (mvebu_mbus_alloc_window(mbus, base, size, MVEBU_MBUS_NO_REMAP,
+ target, attr)) {
+ pr_err("cannot add window '%s', too many windows\n",
+ name);
+ return -ENOMEM;
+ }
+ return 0;
+}
+
+static int __init
+mbus_parse_ranges(struct device_node *node,
+ int *addr_cells, int *c_addr_cells, int *c_size_cells,
+ int *cell_count, const __be32 **ranges_start,
+ const __be32 **ranges_end)
+{
+ const __be32 *prop;
+ int ranges_len, tuple_len;
+
+ /* Allow a node with no 'ranges' property */
+ *ranges_start = of_get_property(node, "ranges", &ranges_len);
+ if (*ranges_start == NULL) {
+ *addr_cells = *c_addr_cells = *c_size_cells = *cell_count = 0;
+ *ranges_start = *ranges_end = NULL;
+ return 0;
+ }
+ *ranges_end = *ranges_start + ranges_len / sizeof(__be32);
+
+ *addr_cells = of_n_addr_cells(node);
+
+ prop = of_get_property(node, "#address-cells", NULL);
+ *c_addr_cells = be32_to_cpup(prop);
+
+ prop = of_get_property(node, "#size-cells", NULL);
+ *c_size_cells = be32_to_cpup(prop);
+
+ *cell_count = *addr_cells + *c_addr_cells + *c_size_cells;
+ tuple_len = (*cell_count) * sizeof(__be32);
+
+ if (ranges_len % tuple_len) {
+ pr_warn("malformed ranges entry '%s'\n", node->name);
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static int __init mbus_dt_setup(struct mvebu_mbus_state *mbus,
+ struct device_node *np)
+{
+ int addr_cells, c_addr_cells, c_size_cells;
+ int i, ret, cell_count;
+ const __be32 *r, *ranges_start, *ranges_end;
+
+ ret = mbus_parse_ranges(np, &addr_cells, &c_addr_cells,
+ &c_size_cells, &cell_count,
+ &ranges_start, &ranges_end);
+ if (ret < 0)
+ return ret;
+
+ for (i = 0, r = ranges_start; r < ranges_end; r += cell_count, i++) {
+ u32 windowid, base, size;
+ u8 target, attr;
+
+ /*
+ * An entry with a non-zero custom field do not
+ * correspond to a static window, so skip it.
+ */
+ windowid = of_read_number(r, 1);
+ if (CUSTOM(windowid))
+ continue;
+
+ target = TARGET(windowid);
+ attr = ATTR(windowid);
+
+ base = of_read_number(r + c_addr_cells, addr_cells);
+ size = of_read_number(r + c_addr_cells + addr_cells,
+ c_size_cells);
+ ret = mbus_dt_setup_win(mbus, base, size, target, attr);
+ if (ret < 0)
+ return ret;
+ }
+ return 0;
+}
+
int __init mvebu_mbus_dt_init(void)
{
struct resource mbuswins_res, sdramwins_res;
@@ -946,6 +1067,10 @@ int __init mvebu_mbus_dt_init(void)
resource_size(&mbuswins_res),
sdramwins_res.start,
resource_size(&sdramwins_res));
- return ret;
+ if (ret)
+ return ret;
+
+ /* Setup statically declared windows in the DT */
+ return mbus_dt_setup(&mbus_state, np);
}
#endif
--
1.8.1.5
More information about the linux-arm-kernel
mailing list