Author: mw Date: Wed Jun 24 12:15:27 2020 New Revision: 362574 URL: https://svnweb.freebsd.org/changeset/base/362574
Log: Fix AccessWidth and BitWidth parsing in SPCR table The ACPI Specification defines a Generic Address Structure (GAS), which is used to describe UART controller register layout in the SPCR table. The driver responsible for parsing it (uart_cpu_acpi) wrongly associates the Access Size field to the uart_bas's regshft and the register BitWidth to the regiowidth - according to the definitions it should be opposite. This problem remained hidden most likely because the majority of platforms use 32-bit registers (BitWidth) which are accessed with the according size (Dword). However on Marvell Armada 8k / Cn913x platforms, the 32-bit registers should be accessed with Byte granulity, which unveiled the issue. This patch fixes above by proper values assignment and slightly improved parsing. Note that handling of the AccessWidth set to EFI_ACPI_6_0_UNDEFINED is needed to work around a buggy SPCR table on EC2 x86 "bare metal" instances. Reviewed by: manu, imp, cperciva, greg_unrelenting.technology Obtained from: Semihalf MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D25373 Modified: head/sys/dev/uart/uart_cpu_acpi.c Modified: head/sys/dev/uart/uart_cpu_acpi.c ============================================================================== --- head/sys/dev/uart/uart_cpu_acpi.c Wed Jun 24 07:25:54 2020 (r362573) +++ head/sys/dev/uart/uart_cpu_acpi.c Wed Jun 24 12:15:27 2020 (r362574) @@ -120,11 +120,46 @@ uart_cpu_acpi_spcr(int devtype, struct uart_devinfo *d (int)spcr->SerialPort.SpaceId); goto out; } - if (spcr->SerialPort.AccessWidth == 0) + switch (spcr->SerialPort.AccessWidth) { + case 0: /* EFI_ACPI_6_0_UNDEFINED */ + /* FALLTHROUGH */ + case 1: /* EFI_ACPI_6_0_BYTE */ + di->bas.regiowidth = 1; + break; + case 2: /* EFI_ACPI_6_0_WORD */ + di->bas.regiowidth = 2; + break; + case 3: /* EFI_ACPI_6_0_DWORD */ + di->bas.regiowidth = 4; + break; + case 4: /* EFI_ACPI_6_0_QWORD */ + di->bas.regiowidth = 8; + break; + default: + printf("UART unsupported access width: %d!\n", + (int)spcr->SerialPort.AccessWidth); + goto out; + } + switch (spcr->SerialPort.BitWidth) { + case 0: + /* FALLTHROUGH */ + case 8: di->bas.regshft = 0; - else - di->bas.regshft = spcr->SerialPort.AccessWidth - 1; - di->bas.regiowidth = spcr->SerialPort.BitWidth / 8; + break; + case 16: + di->bas.regshft = 1; + break; + case 32: + di->bas.regshft = 2; + break; + case 64: + di->bas.regshft = 3; + break; + default: + printf("UART unsupported bit width: %d!\n", + (int)spcr->SerialPort.BitWidth); + goto out; + } switch (spcr->BaudRate) { case 0: /* Special value; means "keep current value unchanged". */ _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"