[PATCH v4 1/2] powerpc/powernv/opal-msglog: Refactor memcons code

[Claudio Carvalho]

On 8/28/19 10:05 AM, Michael Ellerman wrote:
> From: Claudio Carvalho <cclaudio at linux.ibm.com>
>
> This patch refactors the code in opal-msglog that operates on the OPAL
> memory console in order to make it cleaner and also allow the reuse of
> the new memcons_* functions.

Tested-by: Claudio Carvalho <cclaudio at linux.ibm.com>

Thanks,
Claudio

> Signed-off-by: Claudio Carvalho <cclaudio at linux.ibm.com>
> Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
> ---
> v4: mpe: Rename memcons_load_from_dt() to memcons_init().
>          Make memcons_init() and memcons_get_size() non-static.
> 	 Continue to use opal_msglog_copy() in opal_msglog_read().
> ---
>  arch/powerpc/platforms/powernv/opal-msglog.c | 57 +++++++++++++-------
>  1 file changed, 39 insertions(+), 18 deletions(-)
>
> diff --git a/arch/powerpc/platforms/powernv/opal-msglog.c b/arch/powerpc/platforms/powernv/opal-msglog.c
> index dc51d03c6370..d26da19a611f 100644
> --- a/arch/powerpc/platforms/powernv/opal-msglog.c
> +++ b/arch/powerpc/platforms/powernv/opal-msglog.c
> @@ -29,23 +29,23 @@ struct memcons {
>  
>  static struct memcons *opal_memcons = NULL;
>  
> -ssize_t opal_msglog_copy(char *to, loff_t pos, size_t count)
> +ssize_t memcons_copy(struct memcons *mc, char *to, loff_t pos, size_t count)
>  {
>  	const char *conbuf;
>  	ssize_t ret;
>  	size_t first_read = 0;
>  	uint32_t out_pos, avail;
>  
> -	if (!opal_memcons)
> +	if (!mc)
>  		return -ENODEV;
>  
> -	out_pos = be32_to_cpu(READ_ONCE(opal_memcons->out_pos));
> +	out_pos = be32_to_cpu(READ_ONCE(mc->out_pos));
>  
>  	/* Now we've read out_pos, put a barrier in before reading the new
>  	 * data it points to in conbuf. */
>  	smp_rmb();
>  
> -	conbuf = phys_to_virt(be64_to_cpu(opal_memcons->obuf_phys));
> +	conbuf = phys_to_virt(be64_to_cpu(mc->obuf_phys));
>  
>  	/* When the buffer has wrapped, read from the out_pos marker to the end
>  	 * of the buffer, and then read the remaining data as in the un-wrapped
> @@ -53,7 +53,7 @@ ssize_t opal_msglog_copy(char *to, loff_t pos, size_t count)
>  	if (out_pos & MEMCONS_OUT_POS_WRAP) {
>  
>  		out_pos &= MEMCONS_OUT_POS_MASK;
> -		avail = be32_to_cpu(opal_memcons->obuf_size) - out_pos;
> +		avail = be32_to_cpu(mc->obuf_size) - out_pos;
>  
>  		ret = memory_read_from_buffer(to, count, &pos,
>  				conbuf + out_pos, avail);
> @@ -71,7 +71,7 @@ ssize_t opal_msglog_copy(char *to, loff_t pos, size_t count)
>  	}
>  
>  	/* Sanity check. The firmware should not do this to us. */
> -	if (out_pos > be32_to_cpu(opal_memcons->obuf_size)) {
> +	if (out_pos > be32_to_cpu(mc->obuf_size)) {
>  		pr_err("OPAL: memory console corruption. Aborting read.\n");
>  		return -EINVAL;
>  	}
> @@ -86,6 +86,11 @@ ssize_t opal_msglog_copy(char *to, loff_t pos, size_t count)
>  	return ret;
>  }
>  
> +ssize_t opal_msglog_copy(char *to, loff_t pos, size_t count)
> +{
> +	return memcons_copy(opal_memcons, to, pos, count);
> +}
> +
>  static ssize_t opal_msglog_read(struct file *file, struct kobject *kobj,
>  				struct bin_attribute *bin_attr, char *to,
>  				loff_t pos, size_t count)
> @@ -98,32 +103,48 @@ static struct bin_attribute opal_msglog_attr = {
>  	.read = opal_msglog_read
>  };
>  
> -void __init opal_msglog_init(void)
> +struct memcons *memcons_init(struct device_node *node, const char *mc_prop_name)
>  {
>  	u64 mcaddr;
>  	struct memcons *mc;
>  
> -	if (of_property_read_u64(opal_node, "ibm,opal-memcons", &mcaddr)) {
> -		pr_warn("OPAL: Property ibm,opal-memcons not found, no message log\n");
> -		return;
> +	if (of_property_read_u64(node, mc_prop_name, &mcaddr)) {
> +		pr_warn("%s property not found, no message log\n",
> +			mc_prop_name);
> +		goto out_err;
>  	}
>  
>  	mc = phys_to_virt(mcaddr);
>  	if (!mc) {
> -		pr_warn("OPAL: memory console address is invalid\n");
> -		return;
> +		pr_warn("memory console address is invalid\n");
> +		goto out_err;
>  	}
>  
>  	if (be64_to_cpu(mc->magic) != MEMCONS_MAGIC) {
> -		pr_warn("OPAL: memory console version is invalid\n");
> -		return;
> +		pr_warn("memory console version is invalid\n");
> +		goto out_err;
>  	}
>  
> -	/* Report maximum size */
> -	opal_msglog_attr.size =  be32_to_cpu(mc->ibuf_size) +
> -		be32_to_cpu(mc->obuf_size);
> +	return mc;
> +
> +out_err:
> +	return NULL;
> +}
> +
> +u32 memcons_get_size(struct memcons *mc)
> +{
> +	return be32_to_cpu(mc->ibuf_size) + be32_to_cpu(mc->obuf_size);
> +}
> +
> +void __init opal_msglog_init(void)
> +{
> +	opal_memcons = memcons_init(opal_node, "ibm,opal-memcons");
> +	if (!opal_memcons) {
> +		pr_warn("OPAL: memcons failed to load from ibm,opal-memcons\n");
> +		return;
> +	}
>  
> -	opal_memcons = mc;
> +	opal_msglog_attr.size = memcons_get_size(opal_memcons);
>  }
>  
>  void __init opal_msglog_sysfs_init(void)