Commit bd552493 authored by Alex Elder's avatar Alex Elder Committed by Jakub Kicinski
Browse files

net: ipa: no more global filtering starting with IPA v5.0 



IPA v5.0 eliminates the global filter table entry.  As a result,
there is no need to shift the filtered endpoint bitmap when it is
written to IPA local memory.

Update comments to explain this.  Also delete a redundant block of
comments above the function.

Signed-off-by: default avatarAlex Elder <elder@linaro.org>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 5ba5faa2

drivers/net/ipa/ipa_table.c

+35 −24
Original line number Diff line number Diff line
@@ -32,8 +32,8 @@ 
 * endian 64-bit "slot" that holds the address of a rule definition.  (The

 * size of these slots is 64 bits regardless of the host DMA address size.)

 *

 * Separate tables (both filter and route) used for IPv4 and IPv6.  There

 * are normally another set of "hashed" filter and route tables, which are

 * Separate tables (both filter and route) are used for IPv4 and IPv6.  There

 * is normally another set of "hashed" filter and route tables, which are

 * used with a hash of message metadata.  Hashed operation is not supported

 * by all IPA hardware (IPA v4.2 doesn't support hashed tables).

 *
@@ -51,19 +51,32 @@ 
 * Each filter rule is associated with an AP or modem TX endpoint, though

 * not all TX endpoints support filtering.  The first 64-bit slot in a

 * filter table is a bitmap indicating which endpoints have entries in

 * the table.  The low-order bit (bit 0) in this bitmap represents a

 * special global filter, which applies to all traffic.  This is not

 * used in the current code.  Bit 1, if set, indicates that there is an

 * entry (i.e. slot containing a system address referring to a rule) for

 * endpoint 0 in the table.  Bit 3, if set, indicates there is an entry

 * for endpoint 2, and so on.  Space is set aside in IPA local memory to

 * hold as many filter table entries as might be required, but typically

 * they are not all used.

 * the table.  Each set bit in this bitmap indicates the presence of the

 * address of a filter rule in the memory following the bitmap.  Until IPA

 * v5.0,  the low-order bit (bit 0) in this bitmap represents a special

 * global filter, which applies to all traffic.  Otherwise the position of

 * each set bit represents an endpoint for which a filter rule is defined.

 *

 * The global rule is not used in current code, and support for it is

 * removed starting at IPA v5.0.  For IPA v5.0+, the endpoint bitmap

 * position defines the endpoint ID--i.e. if bit 1 is set in the endpoint

 * bitmap, endpoint 1 has a filter rule.  Older versions of IPA represent

 * the presence of a filter rule for endpoint X by bit (X + 1) being set.

 * I.e., bit 1 set indicates the presence of a filter rule for endpoint 0,

 * and bit 3 set means there is a filter rule present for endpoint 2.

 *

 * Each filter table entry has the address of a set of equations that

 * implement a filter rule.  So following the endpoint bitmap there

 * will be such an address/entry for each endpoint with a set bit in

 * the bitmap.

 *

 * The AP initializes all entries in a filter table to refer to a "zero"

 * entry.  Once initialized the modem and AP update the entries for

 * endpoints they "own" directly.  Currently the AP does not use the

 * IPA filtering functionality.

 * rule.  Once initialized, the modem and AP update the entries for

 * endpoints they "own" directly.  Currently the AP does not use the IPA

 * filtering functionality.

 *

 * This diagram shows an example of a filter table with an endpoint

 * bitmap as defined prior to IPA v5.0.

 *

 *                    IPA Filter Table

 *                 ----------------------
@@ -658,12 +671,6 @@ bool ipa_table_mem_valid(struct ipa *ipa, bool filter) 
 * when a route table is initialized or reset, its entries are made to refer

 * to the zero rule.  The zero rule is shared for route and filter tables.

 *

 * Note that the IPA hardware requires a filter or route rule address to be

 * aligned on a 128 byte boundary.  The coherent DMA buffer we allocate here

 * has a minimum alignment, and we place the zero rule at the base of that

 * allocated space.  In ipa_table_init() we verify the minimum DMA allocation

 * meets our requirement.

 *

 *	     +-------------------+

 *	 --> |     zero rule     |

 *	/    |-------------------|
@@ -708,12 +715,16 @@ int ipa_table_init(struct ipa *ipa) 
	/* First slot is the zero rule */

	*virt++ = 0;



	/* Next is the filter table bitmap.  The "soft" bitmap value

	 * must be converted to the hardware representation by shifting

	 * it left one position.  (Bit 0 repesents global filtering,

	 * which is possible but not used.)

	/* Next is the filter table bitmap.  The "soft" bitmap value might

	 * need to be converted to the hardware representation by shifting

	 * it left one position.  Prior to IPA v5.0, bit 0 repesents global

	 * filtering, which is possible but not used.  IPA v5.0+ eliminated

	 * that option, so there's no shifting required.

	 */

	if (ipa->version < IPA_VERSION_5_0)

		*virt++ = cpu_to_le64((u64)ipa->filter_map << 1);

	else

		*virt++ = cpu_to_le64((u64)ipa->filter_map);



	/* All the rest contain the DMA address of the zero rule */

	le_addr = cpu_to_le64(addr);