[PATCH 11/14] ARM: OMAP2+: Add device-tree support for NOR flash
Jon Hunter
jon-hunter at ti.com
Tue Feb 26 12:30:38 EST 2013
NOR flash is not currently supported when booting with device-tree
on OMAP2+ devices. Add support to detect and configure NOR devices
when booting with device-tree.
Add documentation for the TI GPMC NOR binding.
Signed-off-by: Jon Hunter <jon-hunter at ti.com>
---
Documentation/devicetree/bindings/mtd/gpmc-nor.txt | 98 ++++++++++++++++
arch/arm/mach-omap2/gpmc.c | 120 ++++++++++++++++++++
2 files changed, 218 insertions(+)
create mode 100644 Documentation/devicetree/bindings/mtd/gpmc-nor.txt
diff --git a/Documentation/devicetree/bindings/mtd/gpmc-nor.txt b/Documentation/devicetree/bindings/mtd/gpmc-nor.txt
new file mode 100644
index 0000000..8c638fc
--- /dev/null
+++ b/Documentation/devicetree/bindings/mtd/gpmc-nor.txt
@@ -0,0 +1,98 @@
+Device tree bindings for NOR flash connect to TI GPMC
+
+NOR flash connected to the TI GPMC (found on OMAP boards) are represented as
+child nodes of the GPMC controller with a name of "nor".
+
+All timing relevant properties as well as generic GPMC child properties are
+explained in a separate documents. Please refer to
+Documentation/devicetree/bindings/bus/ti-gpmc.txt
+
+Required properties:
+- bank-width: Width of NOR flash in bytes. GPMC supports 8-bit and
+ 16-bit devices and so must be either 1 or 2 bytes.
+- compatible: Documentation/devicetree/bindings/mtd/mtd-physmap.txt
+- gpmc,cs-on: Chip-select assertion time
+- gpmc,cs-rd-off: Chip-select de-assertion time for reads
+- gpmc,cs-wr-off: Chip-select de-assertion time for writes
+- gpmc,oe-on: Output-enable assertion time
+- gpmc,oe-off Output-enable de-assertion time
+- gpmc,we-on: Write-enable assertion time
+- gpmc,we-off: Write-enable de-assertion time
+- gpmc,access: Start cycle to first data capture (read access)
+- gpmc,rd-cycle: Total read cycle time
+- gpmc,wr-cycle: Total write cycle time
+- linux,mtd-name: Documentation/devicetree/bindings/mtd/mtd-physmap.txt
+- reg: Chip-select, base address (relative to chip-select)
+ and size of NOR flash. Note that base address will be
+ typically 0 as this is the start of the chip-select.
+
+Optional properties:
+- gpmc,XXX Additional GPMC timings and settings parameters. See
+ Documentation/devicetree/bindings/bus/ti-gpmc.txt
+
+Optional properties for partiton table parsing:
+- #address-cells: should be set to 1
+- #size-cells: should be set to 1
+
+Example:
+
+gpmc: gpmc at 6e000000 {
+ compatible = "ti,omap3430-gpmc", "simple-bus";
+ ti,hwmods = "gpmc";
+ reg = <0x6e000000 0x1000>;
+ interrupts = <20>;
+ gpmc,num-cs = <8>;
+ gpmc,num-waitpins = <4>;
+ #address-cells = <2>;
+ #size-cells = <1>;
+
+ ranges = <0 0 0x10000000 0x08000000>;
+
+ nor at 0,0 {
+ compatible = "cfi-flash";
+ linux,mtd-name= "intel,pf48f6000m0y1be";
+ #address-cells = <1>;
+ #size-cells = <1>;
+ reg = <0 0 0x08000000>;
+ bank-width = <2>;
+
+ gpmc,mux-add-data;
+ gpmc,cs-on = <0>;
+ gpmc,cs-rd-off = <186>;
+ gpmc,cs-wr-off = <186>;
+ gpmc,adv-on = <12>;
+ gpmc,adv-rd-off = <48>;
+ gpmc,adv-wr-off = <48>;
+ gpmc,oe-on = <54>;
+ gpmc,oe-off = <168>;
+ gpmc,we-on = <54>;
+ gpmc,we-off = <168>;
+ gpmc,rd-cycle = <186>;
+ gpmc,wr-cycle = <186>;
+ gpmc,access = <114>;
+ gpmc,page-burst-access = <6>;
+ gpmc,bus-turnaround = <12>;
+ gpmc,cycle2cycle-delay = <18>;
+ gpmc,wr-data-mux-bus = <90>;
+ gpmc,wr-access = <186>;
+ gpmc,cycle2cycle-samecsen;
+ gpmc,cycle2cycle-diffcsen;
+
+ partition at 0 {
+ label = "bootloader-nor";
+ reg = <0 0x40000>;
+ };
+ partition at 0x40000 {
+ label = "params-nor";
+ reg = <0x40000 0x40000>;
+ };
+ partition at 0x80000 {
+ label = "kernel-nor";
+ reg = <0x80000 0x200000>;
+ };
+ partition at 0x280000 {
+ label = "filesystem-nor";
+ reg = <0x240000 0x7d80000>;
+ };
+ };
+};
diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c
index e822d2b..eb167b3 100644
--- a/arch/arm/mach-omap2/gpmc.c
+++ b/arch/arm/mach-omap2/gpmc.c
@@ -26,6 +26,7 @@
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/of.h>
+#include <linux/of_address.h>
#include <linux/of_mtd.h>
#include <linux/of_device.h>
#include <linux/mtd/nand.h>
@@ -513,6 +514,37 @@ static int gpmc_cs_delete_mem(int cs)
return r;
}
+/**
+ * gpmc_cs_remap - remaps a chip-select physical base address
+ * @cs: chip-select to remap
+ * @base: physical base address to re-map chip-select to
+ *
+ * Re-maps a chip-select to a new physical base address specified by
+ * "base". Returns 0 on success and appropriate negative error code
+ * on failure.
+ */
+static int gpmc_cs_remap(int cs, u32 base)
+{
+ int ret;
+ u32 old_base, size;
+
+ if (cs > GPMC_CS_NUM)
+ return -ENODEV;
+ gpmc_cs_get_memconf(cs, &old_base, &size);
+ if (base == old_base)
+ return 0;
+ gpmc_cs_disable_mem(cs);
+ ret = gpmc_cs_delete_mem(cs);
+ if (IS_ERR_VALUE(ret))
+ return ret;
+ ret = gpmc_cs_insert_mem(cs, base, size);
+ if (IS_ERR_VALUE(ret))
+ return ret;
+ gpmc_cs_enable_mem(cs, base, size);
+
+ return 0;
+}
+
int gpmc_cs_request(int cs, unsigned long size, unsigned long *base)
{
struct resource *res = &gpmc_cs_mem[cs];
@@ -1172,6 +1204,12 @@ int gpmc_cs_program_settings(int cs, struct gpmc_settings *p)
}
#ifdef CONFIG_OF
+static struct property device_disabled = {
+ .name = "status",
+ .length = sizeof("disabled"),
+ .value = "disabled",
+};
+
static struct of_device_id gpmc_dt_ids[] = {
{ .compatible = "ti,omap2420-gpmc" },
{ .compatible = "ti,omap2430-gpmc" },
@@ -1391,6 +1429,79 @@ static int gpmc_probe_onenand_child(struct platform_device *pdev,
}
#endif
+/**
+ * gpmc_probe_nor_child - configures the gpmc for a nor device
+ * @pdev: pointer to gpmc platform device
+ * @child: pointer to device-tree node for nor device
+ *
+ * Allocates and configures a GPMC chip-select for a NOR flash device.
+ * Returns 0 on success and appropriate negative error code on failure.
+ */
+static int gpmc_probe_nor_child(struct platform_device *pdev,
+ struct device_node *child)
+{
+ struct gpmc_settings gpmc_s;
+ struct gpmc_timings gpmc_t;
+ struct resource res;
+ unsigned long base;
+ int ret, cs;
+
+ if (of_property_read_u32(child, "reg", &cs) < 0) {
+ dev_err(&pdev->dev, "%s has no 'reg' property\n",
+ child->full_name);
+ return -ENODEV;
+ }
+
+ if (of_address_to_resource(child, 0, &res)) {
+ dev_err(&pdev->dev, "%s has malformed 'reg' property\n",
+ child->full_name);
+ return -ENODEV;
+ }
+
+ ret = gpmc_cs_request(cs, res.end - res.start, &base);
+ if (IS_ERR_VALUE(ret)) {
+ dev_err(&pdev->dev, "cannot request GPMC CS %d\n", cs);
+ goto err1;
+ }
+
+ /*
+ * FIXME: gpmc_cs_request() will map the CS to an arbitary
+ * location in the gpmc address space. When booting with
+ * device-tree we want the NOR flash to be mapped to the
+ * location specified in the device-tree blob. So remap the
+ * CS to this location. Once DT migration is complete should
+ * just make gpmc_cs_request() map a specific address.
+ */
+ ret = gpmc_cs_remap(cs, res.start);
+ if (IS_ERR_VALUE(ret)) {
+ dev_err(&pdev->dev, "cannot remap GPMC CS %d to 0x%x\n",
+ cs, res.start);
+ goto err2;
+ }
+
+ gpmc_read_settings_dt(child, &gpmc_s);
+
+ ret = of_property_read_u32(child, "bank-width", &gpmc_s.device_width);
+ if (IS_ERR_VALUE(ret))
+ goto err2;
+
+ ret = gpmc_cs_program_settings(cs, &gpmc_s);
+ if (IS_ERR_VALUE(ret))
+ goto err2;
+
+ gpmc_read_timings_dt(child, &gpmc_t);
+ gpmc_cs_set_timings(cs, &gpmc_t);
+
+ return 0;
+err2:
+ gpmc_cs_free(cs);
+err1:
+ /* Prevent registering child device on error */
+ of_add_property(child, &device_disabled);
+
+ return ret;
+}
+
static int gpmc_probe_dt(struct platform_device *pdev)
{
int ret;
@@ -1424,6 +1535,15 @@ static int gpmc_probe_dt(struct platform_device *pdev)
return ret;
}
}
+
+ for_each_node_by_name(child, "nor") {
+ ret = gpmc_probe_nor_child(pdev, child);
+ if (ret < 0) {
+ of_node_put(child);
+ return ret;
+ }
+ }
+
return 0;
}
#else
--
1.7.10.4
More information about the linux-arm-kernel
mailing list