[V3,4/8] pseries/hotplug init: Convert new DRC memory property for hotplug runtime

hotplug_init: Simplify the code needed for runtime memory hotplug and
maintenance with a conversion routine that transforms the compressed
property "ibm,dynamic-memory-v2" to the form of "ibm,dynamic-memory"
within the "ibm,dynamic-reconfiguration-memory" property.  Thus only
a single set of routines should be required at runtime to parse, edit,
and manipulate the memory representation in the device tree.  Similarly,
any userspace applications that need this information will only need
to recognize the older format to be able to continue to operate.

Signed-off-by: Michael Bringmann <mwb@linux.vnet.ibm.com>
---

On 08/01/2016 07:42 PM, Michael Bringmann wrote:
> hotplug_init: Simplify the code needed for runtime memory hotplug and
> maintenance with a conversion routine that transforms the compressed
> property "ibm,dynamic-memory-v2" to the form of "ibm,dynamic-memory"
> within the "ibm,dynamic-reconfiguration-memory" property.  Thus only
> a single set of routines should be required at runtime to parse, edit,
> and manipulate the memory representation in the device tree.  Similarly,
> any userspace applications that need this information will only need
> to recognize the older format to be able to continue to operate.
> 
> Signed-off-by: Michael Bringmann <mwb@linux.vnet.ibm.com>
> ---
> diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
> index 2ce1385..0c46fbc 100644
> --- a/arch/powerpc/platforms/pseries/hotplug-memory.c
> +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
> @@ -24,6 +24,8 @@
>  #include <asm/sparsemem.h>
>  #include "pseries.h"
>  
> +#ifdef CONFIG_MEMORY_HOTPLUG
> +
>  static bool rtas_hp_event;
>  
>  unsigned long pseries_memory_block_size(void)
> @@ -887,11 +889,105 @@ static int pseries_memory_notifier(struct notifier_block *nb,
>  static struct notifier_block pseries_mem_nb = {
>  	.notifier_call = pseries_memory_notifier,
>  };
> +#endif /* CONFIG_MEMORY_HOTPLUG */
> +
> +static int pseries_rewrite_dynamic_memory_v2(void)
> +{
> +	unsigned long memblock_size;
> +	struct device_node *dn;
> +	struct property *prop, *prop_v2;
> +	__be32 *p;
> +	struct of_drconf_cell *lmbs;
> +	u32 num_lmb_desc_sets, num_lmbs;
> +	int i;
> +
> +	dn = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
> +	if (!dn)
> +		return -EINVAL;
> +
> +	prop_v2 = of_find_property(dn, "ibm,dynamic-memory-v2", NULL);
> +	if (!prop_v2)
> +		return -EINVAL;
> +
> +	memblock_size = pseries_memory_block_size();
> +	if (!memblock_size)
> +		return -EINVAL;
> +
> +	/* The first int of the property is the number of lmb sets
> +	 * described by the property.
> +	 */
> +	p = (__be32 *)prop_v2->value;
> +	num_lmb_desc_sets = be32_to_cpu(*p++);
> +
> +	/* Count the number of LMBs for generating the alternate format
> +	 */
> +	for (i = 0, num_lmbs = 0; i < num_lmb_desc_sets; i++) {
> +		struct of_drconf_cell_v2 drmem;
> +
> +		read_drconf_cell_v2(&drmem, (const __be32 **)&p);
> +		num_lmbs += drmem.num_seq_lmbs;
> +	}
> +
> +	/* Create an empty copy of the new 'ibm,dynamic-memory' property
> +	 */
> +	{
> +		prop = kzalloc(sizeof(*prop), GFP_KERNEL);
> +		if (!prop)
> +			return -ENOMEM;
> +		prop->name = kstrdup("ibm,dynamic-memory", GFP_KERNEL);
> +		prop->length = dyn_mem_v2_len(num_lmbs);

Why use a routine to compute the v2 len for v1 property?

> +		prop->value = kzalloc(prop->length, GFP_KERNEL);
> +	}

Also, why is this in its own block?

> +
> +	/* Copy/expand the ibm,dynamic-memory-v2 format to produce the
> +	 * ibm,dynamic-memory format.
> +	 */
> +	p = (__be32 *)prop->value;
> +	*p = cpu_to_be32(num_lmbs);
> +	p++;
> +	lmbs = (struct of_drconf_cell *)p;
> +
> +	p = (__be32 *)prop_v2->value;
> +	p++;
> +
> +	for (i = 0; i < num_lmb_desc_sets; i++) {
> +		struct of_drconf_cell_v2 drmem;
> +		int j, k = 0;

Won't this reset k every time through the loop?

This version of the patch look just like the V2 patch, was
anything changed?

-Nathan
> +
> +		read_drconf_cell_v2(&drmem, (const __be32 **)&p);
> +
> +		for (j = 0; j < drmem.num_seq_lmbs; j++) {
> +			lmbs[k+j].base_addr = be64_to_cpu(drmem.base_addr);
> +			lmbs[k+j].drc_index = be32_to_cpu(drmem.drc_index);
> +			lmbs[k+j].reserved  = 0;
> +			lmbs[k+j].aa_index  = be32_to_cpu(drmem.aa_index);
> +			lmbs[k+i].flags     = be32_to_cpu(drmem.flags);
> +
> +			drmem.base_addr += memblock_size;
> +			drmem.drc_index++;
> +		}
> +
> +		k += drmem.num_seq_lmbs;
> +	}
> +
> +	of_remove_property(dn, prop_v2);
> +
> +	of_add_property(dn, prop);
> +
> +	/* And disable feature flag since the property has gone away */
> +	powerpc_firmware_features &= ~FW_FEATURE_DYN_MEM_V2;
> +
> +	return 0;
> +}
>  
>  static int __init pseries_memory_hotplug_init(void)
>  {
> +	if (firmware_has_feature(FW_FEATURE_DYN_MEM_V2))
> +		pseries_rewrite_dynamic_memory_v2();
> +#ifdef CONFIG_MEMORY_HOTPLUG
>  	if (firmware_has_feature(FW_FEATURE_LPAR))
>  		of_reconfig_notifier_register(&pseries_mem_nb);
> +#endif /* CONFIG_MEMORY_HOTPLUG */
>  
>  	return 0;
>  }
> diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile
> index fedc2ccf0..e74cf6c 100644
> --- a/arch/powerpc/platforms/pseries/Makefile
> +++ b/arch/powerpc/platforms/pseries/Makefile
> @@ -5,14 +5,14 @@ obj-y			:= lpar.o hvCall.o nvram.o reconfig.o \
>  			   of_helpers.o \
>  			   setup.o iommu.o event_sources.o ras.o \
>  			   firmware.o power.o dlpar.o mobility.o rng.o \
> -			   pci.o pci_dlpar.o eeh_pseries.o msi.o
> +			   pci.o pci_dlpar.o eeh_pseries.o msi.o \
> +			   hotplug-memory.o
>  obj-$(CONFIG_SMP)	+= smp.o
>  obj-$(CONFIG_SCANLOG)	+= scanlog.o
>  obj-$(CONFIG_KEXEC)	+= kexec.o
>  obj-$(CONFIG_PSERIES_ENERGY)	+= pseries_energy.o
>  
>  obj-$(CONFIG_HOTPLUG_CPU)	+= hotplug-cpu.o
> -obj-$(CONFIG_MEMORY_HOTPLUG)	+= hotplug-memory.o
>  
>  obj-$(CONFIG_HVC_CONSOLE)	+= hvconsole.o
>  obj-$(CONFIG_HVCS)		+= hvcserver.o
> 
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