Hello.
John Crispin wrote:
This patch adds the driver/map for NOR devices attached to the SoC via the
External Bus Unit (EBU).
Signed-off-by: John Crispin <blogic@xxxxxxxxxxx>
Signed-off-by: Ralph Hempel <ralph.hempel@xxxxxxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Cc: Daniel Schwierzeck <daniel.schwierzeck@xxxxxxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Cc: linux-mtd@xxxxxxxxxxxxxxxxxxx
diff --git a/drivers/mtd/maps/lantiq.c b/drivers/mtd/maps/lantiq.c
new file mode 100644
index 0000000..4f8c320
--- /dev/null
+++ b/drivers/mtd/maps/lantiq.c
@@ -0,0 +1,197 @@
[...]
+/*
+ * The NOR flash is connected to the same external bus unit (EBU) as PCI.
+ * To make PCI work we need to enable the endianess swapping for the address
s/endianess/endianness/
+ * written to the EBU. This endianess swapping works for PCI correctly but
Here too.
+ * fails for attached NOR devices. To workaround this we need to use a complex
+ * map. The workaround involves swapping all addresses whilste probing the chip.
s/whilste/whilst/
+ * Once probing is complete we stop swapping the addresses but swizzle the
+ * unlock addresses to ensure that access to the NOR device works correctly.
+ */
+
+enum ltq_nor_state {
+ LTQ_NOR_PROBING,
+ LTQ_NOR_NORMAL
+};
+
+static char ltq_map_name[] = "ltq_nor";
+
+static map_word
+ltq_read16(struct map_info *map, unsigned long adr)
+{
+ unsigned long flags;
+ map_word temp;
+
+ if (map->map_priv_1 == LTQ_NOR_PROBING)
+ adr ^= 2;
+ spin_lock_irqsave(&ebu_lock, flags);
+ temp.x[0] = *((__u16 *)(map->virt + adr));
Too many parens; the most external ones are not necessary.
And why not just 'u16'?
+ spin_unlock_irqrestore(&ebu_lock, flags);
+ return temp;
+}
+
+static void
+ltq_write16(struct map_info *map, map_word d, unsigned long adr)
+{
+ unsigned long flags;
+
+ if (map->map_priv_1 == LTQ_NOR_PROBING)
+ adr ^= 2;
+ spin_lock_irqsave(&ebu_lock, flags);
+ *((__u16 *)(map->virt + adr)) = d.x[0];
Same here.
+ spin_unlock_irqrestore(&ebu_lock, flags);
+}
+
+/*
+ * The following 2 functions copy data between iomem and a cached memory
+ * section. As memcpy() makes use of pre-fetching we cannot use it here.
+ * The normal alternative of using memcpy_{to,from}io also makes use of
+ * memcpy() on MIPS so it is not applicable either. We are therefore stuck
+ * with having to use our own loop.
+ */
+static void
+ltq_copy_from(struct map_info *map, void *to,
+ unsigned long from, ssize_t len)
+{
+ unsigned char *f = (unsigned char *) (map->virt + from);
+ unsigned char *t = (unsigned char *) to;
I think you should either always put a space between the type and value
being cast or not -- you do both. :-)
+ unsigned long flags;
+
+ spin_lock_irqsave(&ebu_lock, flags);
+ while (len--)
+ *t++ = *f++;
I'm still not sure: you've implemented only 16-bit single read/write, yet
you copy byte-by-byte? Does the byte access really work?
+ spin_unlock_irqrestore(&ebu_lock, flags);
+}
+
[...]
+static int __init
+ltq_mtd_probe(struct platform_device *pdev)
+{
+ struct physmap_flash_data *ltq_mtd_data = dev_get_platdata(&pdev->dev);
+ struct mtd_info *ltq_mtd = NULL;
+ struct mtd_partition *parts = NULL;
+ struct resource *res;
+ int nr_parts = 0;
+ struct cfi_private *cfi;
+ struct map_info *ltq_map;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(&pdev->dev, "failed to get memory resource");
+ return -ENOENT;
+ }
+ res = devm_request_mem_region(&pdev->dev, res->start,
+ resource_size(res), dev_name(&pdev->dev));
+ if (!res) {
+ dev_err(&pdev->dev, "failed to request mem resource");
+ return -EBUSY;
+ }
+
+ ltq_map = kzalloc(sizeof(struct map_info), GFP_KERNEL);
+ ltq_map->phys = res->start;
+ ltq_map->size = resource_size(res);
+ ltq_map->virt = devm_ioremap_nocache(&pdev->dev, ltq_map->phys,
+ ltq_map->size);
+ if (!ltq_map->virt) {
+ kfree(ltq_map);
You should do error cleanup in one places, using *goto* to jump to that code,
to avoid duplicating the same code.
+ dev_err(&pdev->dev, "failed to ioremap!\n");
+ return -EIO;
Rather -ENOMEM.
[...]
+int __init
+init_ltq_mtd(void)
+{
+ int ret = platform_driver_probe(<q_mtd_driver, ltq_mtd_probe);
+
+ if (ret)
+ pr_err("ltq_nor: error registering platfom driver");
s/platfom/platform/
+ return ret;
+}
+
+module_init(init_ltq_mtd);
How about module_exit()?
WBR, Sergei
