From mboxrd@z Thu Jan  1 00:00:00 1970
From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Date: Sat, 28 Dec 2013 11:35:31 +0000
Subject: Re: [PATCH 2/2] clk: shmobile: Fix MSTP clock array initialization
Message-Id: <2496568.7xyIE9TFWS@avalon>
List-Id: <linux-sh.vger.kernel.org>
References: <1388167599-23525-3-git-send-email-valentine.barshak@cogentembedded.com>
In-Reply-To: <1388167599-23525-3-git-send-email-valentine.barshak@cogentembedded.com>
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To: linux-sh@vger.kernel.org

Hi Valentine,

On Friday 27 December 2013 22:06:39 Valentine Barshak wrote:
> The clks member of the clk_onecell_data structure should
> point to a valid clk array (no NULL entries allowed),
> and the clk_num should be equal to the number
> of elements in the clks array.
> 
> The MSTP driver fails to satisfy the above conditions.
> The clks array may contain NULL entries if not all
> clock-indices are initialized in the device tree.
> Thus, if the clock indices are interleaved we end up
> with NULL pointers in-between.

I don't think that's an issue in practice as long as no reference to a NULL 
clock exists in the device tree, but it should of course be fixed.

> The other problem is the driver uses maximum clock index
> as the number of clocks, which is incorrect (less than
> the actual number of clocks by 1).

Good catch.

> Fix the first issue by pre-setting the whole clks array
> with ERR_PTR(-ENOENT) pointers instead of zeros; and
> use maximum clkidx + 1 as the number of clocks to fix
> the other one.
> 
> This should make of_clk_src_onecell_get() return the following:
> * valid clk pointers for all clocks registered;
> * ERR_PTR(-EINVAL) if (idx >= clk_data->clk_num);
> * ERR_PTR(-ENOENT) if the clock at the selected index was not
>   initialized in the device tree (and was not registered).
> 
> Signed-off-by: Valentine Barshak <valentine.barshak@cogentembedded.com>
> ---
>  drivers/clk/shmobile/clk-mstp.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/clk/shmobile/clk-mstp.c
> b/drivers/clk/shmobile/clk-mstp.c index be7d017..14b91ad 100644
> --- a/drivers/clk/shmobile/clk-mstp.c
> +++ b/drivers/clk/shmobile/clk-mstp.c
> @@ -160,7 +160,7 @@ static void __init cpg_mstp_clocks_init(struct
> device_node *np) unsigned int i;
> 
>  	group = kzalloc(sizeof(*group), GFP_KERNEL);
> -	clks = kzalloc(MSTP_MAX_CLOCKS * sizeof(*clks), GFP_KERNEL);
> +	clks = kmalloc(MSTP_MAX_CLOCKS * sizeof(*clks), GFP_KERNEL);
>  	if (group = NULL || clks = NULL) {
>  		kfree(group);
>  		kfree(clks);
> @@ -182,6 +182,10 @@ static void __init cpg_mstp_clocks_init(struct
> device_node *np) }
> 
>  	for (i = 0; i < MSTP_MAX_CLOCKS; ++i) {
> +		clks[i] = ERR_PTR(-ENOENT);
> +	}

No need for brackets here.

With this fixed,

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> +
> +	for (i = 0; i < MSTP_MAX_CLOCKS; ++i) {
>  		const char *parent_name;
>  		const char *name;
>  		u32 clkidx;
> @@ -208,7 +212,8 @@ static void __init cpg_mstp_clocks_init(struct
> device_node *np) clks[clkidx] = cpg_mstp_clock_register(name, parent_name,
>  						       clkidx, group);
>  		if (!IS_ERR(clks[clkidx])) {
> -			group->data.clk_num = max(group->data.clk_num, clkidx);
> +			group->data.clk_num = max(group->data.clk_num,
> +						  clkidx + 1);
>  			/*
>  			 * Register a clkdev to let board code retrieve the
>  			 * clock by name and register aliases for non-DT
-- 
Regards,

Laurent Pinchart