Bjorn,
On 02/07/2014 04:49 PM, Bjorn Andersson wrote:
On Mon, Jan 13, 2014 at 4:19 PM, Suman Anna <s-anna@xxxxxx> wrote:
This patch adds three new OF helper functions to use/request
locks from a hwspinlock device instantiated through a
device-tree blob.
Nice, I ran in to the problem of needing a probe deferral on a
hwspinlock earlier this week so I implemented this yesterday...then I
got a pointer to your series.
[snip]
/**
+ * of_hwspin_lock_request_specific() - request a OF phandle-based specific lock
+ * @np: device node from which to request the specific hwlock
+ * @propname: property name containing hwlock specifier(s)
+ * @index: index of the hwlock
+ *
+ * This function is the OF equivalent of hwspin_lock_request_specific(). This
+ * function provides a means for users of the hwspinlock module to request a
+ * specific hwspinlock using the phandle of the hwspinlock device. The requested
+ * lock number is indexed relative to the hwspinlock device, unlike the
+ * hwspin_lock_request_specific() which is an absolute lock number.
+ *
+ * Returns the address of the assigned hwspinlock, or NULL on error
+ */
+struct hwspinlock *of_hwspin_lock_request_specific(struct device_node *np,
+ const char *propname, int index)
+{
+ struct hwspinlock_device *bank;
+ struct of_phandle_args args;
+ int id;
+ int ret;
+
+ ret = of_parse_phandle_with_args(np, propname, "#hwlock-cells", index,
+ &args);
+ if (ret) {
+ pr_warn("%s: can't parse hwlocks property of node '%s[%d]' ret = %d\n",
+ __func__, np->full_name, index, ret);
+ return NULL;
+ }
of_parse_phandle_with_args() already does pr_err if it can't find the
phandle and on some of the issues related to arguments. So please
remove this pr_warn().
Yes, I will clean this up.
It seems to be standard practice to pass the error value back to the
consumer, so you should
return ERR_PTR(ret); here instead of the NULL...
I have modelled the return values in this function based on the return
values in the existing hwspin_lock_request interfaces. I would need to
change those functions as well.
Ohad,
Do you have any objections to the return code convention change? I agree
with Bjorn on the changes. If you are ok, then I will add a separate
patch for the existing functions and revise this patch as well.
+
+ mutex_lock(&hwspinlock_tree_lock);
+ list_for_each_entry(bank, &hwspinlock_devices, list)
+ if (bank->dev->of_node == args.np)
+ break;
+ mutex_unlock(&hwspinlock_tree_lock);
+ if (&bank->list == &hwspinlock_devices) {
+ pr_warn("%s: requested hwspinlock device %s is not registered\n",
+ __func__, args.np->full_name);
+ return NULL;
...especially since you want the consumer to have the ability to
identify this error. Here you should
return ERR_PTR(-EPROBE_DEFER); so that the consumer knows that this
lock is not _yet_ registered, but will be in the future.
You should remove this pr_warn as well. The standard use of this
function would be in a probe() and just returning this error value
from that probe will give you a line in the log indicating that this
was in fact the issue.
OK.
+ }
+
+ id = bank->ops->of_xlate(bank, &args);
+ if (id < 0 || id >= bank->num_locks) {
+ pr_warn("%s: requested lock %d is either out of range [0, %d] or failed translation\n",
+ __func__, id, bank->num_locks - 1);
+ return NULL;
Please return ERR_PTR(-EINVAL); here.
OK, will change this based on Ohad's ack/nack.
Looking forward to your next spin, as I will actually use this interface :)
Thanks for your comments. I will wait to see if there are any additional
comments before I refresh the series later this week.
regards
Suman
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