mirror of
https://github.com/torvalds/linux.git
synced 2024-12-02 09:01:34 +00:00
b02002cc4c
With our current support for the new MIO PCI instructions, write combining/write back MMIO memory can be obtained via the pci_iomap_wc() and pci_iomap_wc_range() functions. This is achieved by using the write back address for a specific bar as provided in clp_store_query_pci_fn() These functions are however not widely used and instead drivers often rely on ioremap_wc() and ioremap_prot(), which on other platforms enable write combining using a PTE flag set through the pgrprot value. While we do not have a write combining flag in the low order flag bits of the PTE like x86_64 does, with MIO support, there is a write back bit in the physical address (bit 1 on z15) and thus also the PTE. Which bit is used to toggle write back and whether it is available at all, is however not fixed in the architecture. Instead we get this information from the CLP Store Logical Processor Characteristics for PCI command. When the write back bit is not provided we fall back to the existing behavior. Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Reviewed-by: Pierre Morel <pmorel@linux.ibm.com> Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
60 lines
1.4 KiB
C
60 lines
1.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _ASM_S390_CLP_H
|
|
#define _ASM_S390_CLP_H
|
|
|
|
/* CLP common request & response block size */
|
|
#define CLP_BLK_SIZE PAGE_SIZE
|
|
|
|
/* Call Logical Processor - Command Code */
|
|
#define CLP_SLPC 0x0001
|
|
|
|
#define CLP_LPS_BASE 0
|
|
#define CLP_LPS_PCI 2
|
|
|
|
struct clp_req_hdr {
|
|
u16 len;
|
|
u16 cmd;
|
|
u32 fmt : 4;
|
|
u32 reserved1 : 28;
|
|
u64 reserved2;
|
|
} __packed;
|
|
|
|
struct clp_rsp_hdr {
|
|
u16 len;
|
|
u16 rsp;
|
|
u32 fmt : 4;
|
|
u32 reserved1 : 28;
|
|
u64 reserved2;
|
|
} __packed;
|
|
|
|
/* CLP Response Codes */
|
|
#define CLP_RC_OK 0x0010 /* Command request successfully */
|
|
#define CLP_RC_CMD 0x0020 /* Command code not recognized */
|
|
#define CLP_RC_PERM 0x0030 /* Command not authorized */
|
|
#define CLP_RC_FMT 0x0040 /* Invalid command request format */
|
|
#define CLP_RC_LEN 0x0050 /* Invalid command request length */
|
|
#define CLP_RC_8K 0x0060 /* Command requires 8K LPCB */
|
|
#define CLP_RC_RESNOT0 0x0070 /* Reserved field not zero */
|
|
#define CLP_RC_NODATA 0x0080 /* No data available */
|
|
#define CLP_RC_FC_UNKNOWN 0x0100 /* Function code not recognized */
|
|
|
|
/* Store logical-processor characteristics request */
|
|
struct clp_req_slpc {
|
|
struct clp_req_hdr hdr;
|
|
} __packed;
|
|
|
|
struct clp_rsp_slpc {
|
|
struct clp_rsp_hdr hdr;
|
|
u32 reserved2[4];
|
|
u32 lpif[8];
|
|
u32 reserved3[8];
|
|
u32 lpic[8];
|
|
} __packed;
|
|
|
|
struct clp_req_rsp_slpc {
|
|
struct clp_req_slpc request;
|
|
struct clp_rsp_slpc response;
|
|
} __packed;
|
|
|
|
#endif
|