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Commit 53e80bd0 authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Michael Ellerman
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powerpc/nvdimm: Add support for multibyte read/write for metadata 



SCM_READ/WRITE_MEATADATA hcall supports multibyte read/write. This patch
updates the metadata read/write to use 1, 2, 4 or 8 byte read/write as
mentioned in PAPR document.

READ/WRITE_METADATA hcall supports the 1, 2, 4, or 8 bytes read/write.
For other values hcall results H_P3.

Hypervisor stores the metadata contents in big-endian format and in-order
to enable read/write in different granularity, we need to switch the contents
to big-endian before calling HCALL.

Based on an patch from Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 2a0ffbd4

arch/powerpc/platforms/pseries/papr_scm.c

+82 −22
Original line number Diff line number Diff line
@@ -100,39 +100,99 @@ static int papr_scm_meta_get(struct papr_scm_priv *p, 
			     struct nd_cmd_get_config_data_hdr *hdr)

{

	unsigned long data[PLPAR_HCALL_BUFSIZE];

	unsigned long offset, data_offset;

	int len, read;

	int64_t ret;



	if (hdr->in_offset >= p->metadata_size || hdr->in_length != 1)

	if ((hdr->in_offset + hdr->in_length) >= p->metadata_size)

		return -EINVAL;



	for (len = hdr->in_length; len; len -= read) {



		data_offset = hdr->in_length - len;

		offset = hdr->in_offset + data_offset;



		if (len >= 8)

			read = 8;

		else if (len >= 4)

			read = 4;

		else if (len >= 2)

			read = 2;

		else

			read = 1;



		ret = plpar_hcall(H_SCM_READ_METADATA, data, p->drc_index,

			hdr->in_offset, 1);

				  offset, read);



		if (ret == H_PARAMETER) /* bad DRC index */

			return -ENODEV;

		if (ret)

			return -EINVAL; /* other invalid parameter */



	hdr->out_buf[0] = data[0] & 0xff;

		switch (read) {

		case 8:

			*(uint64_t *)(hdr->out_buf + data_offset) = be64_to_cpu(data[0]);

			break;

		case 4:

			*(uint32_t *)(hdr->out_buf + data_offset) = be32_to_cpu(data[0] & 0xffffffff);

			break;



		case 2:

			*(uint16_t *)(hdr->out_buf + data_offset) = be16_to_cpu(data[0] & 0xffff);

			break;



		case 1:

			*(uint8_t *)(hdr->out_buf + data_offset) = (data[0] & 0xff);

			break;

		}

	}

	return 0;

}



static int papr_scm_meta_set(struct papr_scm_priv *p,

			     struct nd_cmd_set_config_hdr *hdr)

{

	unsigned long offset, data_offset;

	int len, wrote;

	unsigned long data;

	__be64 data_be;

	int64_t ret;



	if (hdr->in_offset >= p->metadata_size || hdr->in_length != 1)

	if ((hdr->in_offset + hdr->in_length) >= p->metadata_size)

		return -EINVAL;



	ret = plpar_hcall_norets(H_SCM_WRITE_METADATA,

			p->drc_index, hdr->in_offset, hdr->in_buf[0], 1);

	for (len = hdr->in_length; len; len -= wrote) {



		data_offset = hdr->in_length - len;

		offset = hdr->in_offset + data_offset;



		if (len >= 8) {

			data = *(uint64_t *)(hdr->in_buf + data_offset);

			data_be = cpu_to_be64(data);

			wrote = 8;

		} else if (len >= 4) {

			data = *(uint32_t *)(hdr->in_buf + data_offset);

			data &= 0xffffffff;

			data_be = cpu_to_be32(data);

			wrote = 4;

		} else if (len >= 2) {

			data = *(uint16_t *)(hdr->in_buf + data_offset);

			data &= 0xffff;

			data_be = cpu_to_be16(data);

			wrote = 2;

		} else {

			data_be = *(uint8_t *)(hdr->in_buf + data_offset);

			data_be &= 0xff;

			wrote = 1;

		}



		ret = plpar_hcall_norets(H_SCM_WRITE_METADATA, p->drc_index,

					 offset, data_be, wrote);

		if (ret == H_PARAMETER) /* bad DRC index */

			return -ENODEV;

		if (ret)

			return -EINVAL; /* other invalid parameter */

	}



	return 0;

}
@@ -154,7 +214,7 @@ int papr_scm_ndctl(struct nvdimm_bus_descriptor *nd_desc, struct nvdimm *nvdimm, 
		get_size_hdr = buf;



		get_size_hdr->status = 0;

		get_size_hdr->max_xfer = 1;

		get_size_hdr->max_xfer = 8;

		get_size_hdr->config_size = p->metadata_size;

		*cmd_rc = 0;

		break;