1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
4  * Module Name: hwregs - Read/write access functions for the various ACPI
19 acpi_hw_get_access_bit_width(u64 address,
39  * PARAMETERS:  address             - GAS register address
40  *              reg                 - GAS register structure
41  *              max_bit_width       - Max bit_width supported (32 or 64)
50 acpi_hw_get_access_bit_width(u64 address,  in acpi_hw_get_access_bit_width()  argument
66 	 * Note: This algorithm assumes that the "Address" fields should always  in acpi_hw_get_access_bit_width()
69 	if (!reg->bit_offset && reg->bit_width &&  in acpi_hw_get_access_bit_width()
70 	    ACPI_IS_POWER_OF_TWO(reg->bit_width) &&  in acpi_hw_get_access_bit_width()
71 	    ACPI_IS_ALIGNED(reg->bit_width, 8)) {  in acpi_hw_get_access_bit_width()
72 		access_bit_width = reg->bit_width;  in acpi_hw_get_access_bit_width()
73 	} else if (reg->access_width) {  in acpi_hw_get_access_bit_width()
74 		access_bit_width = ACPI_ACCESS_BIT_WIDTH(reg->access_width);  in acpi_hw_get_access_bit_width()
77 		    ACPI_ROUND_UP_POWER_OF_TWO_8(reg->bit_offset +  in acpi_hw_get_access_bit_width()
78 						 reg->bit_width);  in acpi_hw_get_access_bit_width()
82 			while (!ACPI_IS_ALIGNED(address, access_bit_width >> 3)) {  in acpi_hw_get_access_bit_width()
90 	if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {  in acpi_hw_get_access_bit_width()
97 	 * a 32-bit accesses.  in acpi_hw_get_access_bit_width()
109  * PARAMETERS:  reg                 - GAS register structure
110  *              max_bit_width       - Max bit_width supported (32 or 64)
111  *              address             - Pointer to where the gas->address
117  *              pointer, Address, space_id, bit_width, and bit_offset.
123 			  u8 max_bit_width, u64 *address)  in acpi_hw_validate_register()  argument
135 	 * Copy the target address. This handles possible alignment issues.  in acpi_hw_validate_register()
136 	 * Address must not be null. A null address also indicates an optional  in acpi_hw_validate_register()
139 	ACPI_MOVE_64_TO_64(address, &reg->address);  in acpi_hw_validate_register()
140 	if (!(*address)) {  in acpi_hw_validate_register()
146 	if ((reg->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) &&  in acpi_hw_validate_register()
147 	    (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO)) {  in acpi_hw_validate_register()
149 			    "Unsupported address space: 0x%X", reg->space_id));  in acpi_hw_validate_register()
155 	if (reg->access_width > 4) {  in acpi_hw_validate_register()
158 			    reg->access_width));  in acpi_hw_validate_register()
162 	/* Validate the bit_width, convert access_width into number of bits */  in acpi_hw_validate_register()
165 	    acpi_hw_get_access_bit_width(*address, reg, max_bit_width);  in acpi_hw_validate_register()
167 	    ACPI_ROUND_UP(reg->bit_offset + reg->bit_width, access_width);  in acpi_hw_validate_register()
182  * PARAMETERS:  value               - Where the value is returned
183  *              reg                 - GAS register structure
187  * DESCRIPTION: Read from either memory or IO space. This is a 64-bit max
197 	u64 address;  in acpi_hw_read()  local
210 	status = acpi_hw_validate_register(reg, 64, &address);  in acpi_hw_read()
216 	 * Initialize entire 64-bit return value to zero, convert access_width  in acpi_hw_read()
217 	 * into number of bits based  in acpi_hw_read()
220 	access_width = acpi_hw_get_access_bit_width(address, reg, 64);  in acpi_hw_read()
221 	bit_width = reg->bit_offset + reg->bit_width;  in acpi_hw_read()
222 	bit_offset = reg->bit_offset;  in acpi_hw_read()
225 	 * Two address spaces supported: Memory or IO. PCI_Config is  in acpi_hw_read()
232 			bit_offset -= access_width;  in acpi_hw_read()
234 			if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {  in acpi_hw_read()
237 							address +  in acpi_hw_read()
245 							   address +  in acpi_hw_read()
257 		 * ensured to be less than 64-bits by acpi_hw_validate_register().  in acpi_hw_read()
262 		bit_width -=  in acpi_hw_read()
270 			  ACPI_FORMAT_UINT64(address),  in acpi_hw_read()
271 			  acpi_ut_get_region_name(reg->space_id)));  in acpi_hw_read()
280  * PARAMETERS:  value               - Value to be written
281  *              reg                 - GAS register structure
285  * DESCRIPTION: Write to either memory or IO space. This is a 64-bit max
292 	u64 address;  in acpi_hw_write()  local
304 	status = acpi_hw_validate_register(reg, 64, &address);  in acpi_hw_write()
309 	/* Convert access_width into number of bits based */  in acpi_hw_write()
311 	access_width = acpi_hw_get_access_bit_width(address, reg, 64);  in acpi_hw_write()
312 	bit_width = reg->bit_offset + reg->bit_width;  in acpi_hw_write()
313 	bit_offset = reg->bit_offset;  in acpi_hw_write()
316 	 * Two address spaces supported: Memory or IO. PCI_Config is  in acpi_hw_write()
323 		 * ensured to be less than 64-bits by acpi_hw_validate_register().  in acpi_hw_write()
329 			bit_offset -= access_width;  in acpi_hw_write()
331 			if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {  in acpi_hw_write()
334 							 address +  in acpi_hw_write()
342 							    address +  in acpi_hw_write()
352 		 * Index * access_width is ensured to be less than 32-bits by  in acpi_hw_write()
355 		bit_width -=  in acpi_hw_write()
363 			  ACPI_FORMAT_UINT64(address),  in acpi_hw_write()
364 			  acpi_ut_get_region_name(reg->space_id)));  in acpi_hw_write()
378  * DESCRIPTION: Clears all fixed and general purpose status bits
391 			  ACPI_FORMAT_UINT64(acpi_gbl_xpm1a_status.address)));  in acpi_hw_clear_acpi_status()
406 	/* Clear the GPE Bits in all GPE registers in all GPE blocks */  in acpi_hw_clear_acpi_status()
418  * PARAMETERS:  register_id         - Index of ACPI Register to access
443  * PARAMETERS:  pm1a_control        - Value to be written to PM1A control
444  *              pm1b_control        - Value to be written to PM1B control
451  *              Most notably, the SLP_TYP bits can be different, as per the
468 	if (acpi_gbl_FADT.xpm1b_control_block.address) {  in acpi_hw_write_pm1_control()
480  * PARAMETERS:  register_id         - ACPI Register ID
481  *              return_value        - Where the register value is returned
497 	case ACPI_REGISTER_PM1_STATUS:	/* PM1 A/B: 16-bit access each */  in acpi_hw_register_read()
504 	case ACPI_REGISTER_PM1_ENABLE:	/* PM1 A/B: 16-bit access each */  in acpi_hw_register_read()
511 	case ACPI_REGISTER_PM1_CONTROL:	/* PM1 A/B: 16-bit access each */  in acpi_hw_register_read()
520 		 * Zero the write-only bits. From the ACPI specification, "Hardware  in acpi_hw_register_read()
521 		 * Write-Only Bits": "Upon reads to registers with write-only bits,  in acpi_hw_register_read()
522 		 * software masks out all write-only bits."  in acpi_hw_register_read()
527 	case ACPI_REGISTER_PM2_CONTROL:	/* 8-bit access */  in acpi_hw_register_read()
536 	case ACPI_REGISTER_PM_TIMER:	/* 32-bit access */  in acpi_hw_register_read()
545 	case ACPI_REGISTER_SMI_COMMAND_BLOCK:	/* 8-bit access */  in acpi_hw_register_read()
569  * PARAMETERS:  register_id         - ACPI Register ID
570  *              value               - The value to write
577  * preserves the value of the following bits, meaning that these bits cannot be
585  * 1) Hardware Ignored Bits: When software writes to a register with ignored
600 	case ACPI_REGISTER_PM1_STATUS:	/* PM1 A/B: 16-bit access each */  in acpi_hw_register_write()
603 		 * specification, ignored bits are to be preserved when writing.  in acpi_hw_register_write()
618 	case ACPI_REGISTER_PM1_ENABLE:	/* PM1 A/B: 16-bit access each */  in acpi_hw_register_write()
625 	case ACPI_REGISTER_PM1_CONTROL:	/* PM1 A/B: 16-bit access each */  in acpi_hw_register_write()
627 		 * Perform a read first to preserve certain bits (per ACPI spec)  in acpi_hw_register_write()
639 		/* Insert the bits to be preserved */  in acpi_hw_register_write()
653 	case ACPI_REGISTER_PM2_CONTROL:	/* 8-bit access */  in acpi_hw_register_write()
655 		 * For control registers, all reserved bits must be preserved,  in acpi_hw_register_write()
666 		/* Insert the bits to be preserved */  in acpi_hw_register_write()
675 	case ACPI_REGISTER_PM_TIMER:	/* 32-bit access */  in acpi_hw_register_write()
680 	case ACPI_REGISTER_SMI_COMMAND_BLOCK:	/* 8-bit access */  in acpi_hw_register_write()
703  * PARAMETERS:  value               - Where the register value is returned
704  *              register_a           - First ACPI register (required)
705  *              register_b           - Second ACPI register (optional)
709  * DESCRIPTION: Read from the specified two-part ACPI register (such as PM1 A/B)
733 	if (register_b->address) {  in acpi_hw_read_multiple()
745 	 * "Although the bits can be split between the two register blocks (each  in acpi_hw_read_multiple()
747 	 * are maintained. The register block with unimplemented bits (that is,  in acpi_hw_read_multiple()
759  * PARAMETERS:  value               - The value to write
760  *              register_a           - First ACPI register (required)
761  *              register_b           - Second ACPI register (optional)
765  * DESCRIPTION: Write to the specified two-part ACPI register (such as PM1 A/B)
789 	 * "Although the bits can be split between the two register blocks (each  in acpi_hw_write_multiple()
791 	 * are maintained. The register block with unimplemented bits (that is,  in acpi_hw_write_multiple()
795 	if (register_b->address) {  in acpi_hw_write_multiple()