After enabling TrustZone various parts of the CAAM silicon become inaccessible to non TrustZone contexts. The job-ring registers are designed to allow non TrustZone contexts like Linux to still submit jobs to CAAM even after TrustZone has been enabled.
The default job-ring permissions after the BootROM look like this for job-ring zero. ms=0x00008001 ls=0x00008001 The MS field is JRaMIDR_MS (job ring MID most significant). Referring to "Security Reference Manual for i.MX 7Dual and 7Solo Applications Processors, Rev. 0, 03/2017" section 8.10.4 we see that JROWN_NS controls whether or not a job-ring is accessible from non TrustZone. Bit 15 (TrustZone) is the logical inverse of bit 3 hence the above value of 0x8001 shows that JROWN_NS=0 and TrustZone=1. Clearly then as soon as TrustZone becomes active the job-ring registers are no longer accessible from Linux, which is not what we want. This patch explicitly sets all job-ring registers to JROWN_NS=1 (non TrustZone) by default. If a piece of TrustZone firmware requires ownership of job-ring registers it can unset the JROWN_NS bit itself. This patch in conjunction with a modification of the Linux kernel to skip HWRNG initialisation makes CAAM usable to Linux with TrustZone enabled. Signed-off-by: Bryan O'Donoghue <bryan.odonog...@linaro.org> Cc: Fabio Estevam <fabio.este...@nxp.com> Cc: Peng Fan <peng....@nxp.com> Cc: Alex Porosanu <alexandru.poros...@nxp.com> Cc: Ruchika Gupta <ruchika.gu...@nxp.com> Cc: Aneesh Bansal <aneesh.ban...@nxp.com> Link: https://github.com/OP-TEE/optee_os/issues/1408 Link: https://tinyurl.com/yam5gv9a --- drivers/crypto/fsl/jr.c | 9 +++++++++ drivers/crypto/fsl/jr.h | 1 + 2 files changed, 10 insertions(+) diff --git a/drivers/crypto/fsl/jr.c b/drivers/crypto/fsl/jr.c index 986eabf..cbf570d 100644 --- a/drivers/crypto/fsl/jr.c +++ b/drivers/crypto/fsl/jr.c @@ -566,6 +566,8 @@ int sec_init_idx(uint8_t sec_idx) { ccsr_sec_t *sec = (void *)SEC_ADDR(sec_idx); uint32_t mcr = sec_in32(&sec->mcfgr); + uint32_t jrown_ns; + int i; int ret = 0; #ifdef CONFIG_FSL_CORENET @@ -621,6 +623,13 @@ int sec_init_idx(uint8_t sec_idx) #endif #endif + /* Set ownership of job rings to non-TrustZone mode by default */ + for (i = 0; i < ARRAY_SIZE(sec->jrliodnr); i++) { + jrown_ns = sec_in32(&sec->jrliodnr[i].ms); + jrown_ns |= JROWN_NS; + sec_out32(&sec->jrliodnr[i].ms, jrown_ns); + } + ret = jr_init(sec_idx); if (ret < 0) { printf("SEC initialization failed\n"); diff --git a/drivers/crypto/fsl/jr.h b/drivers/crypto/fsl/jr.h index d897e57..72f7501 100644 --- a/drivers/crypto/fsl/jr.h +++ b/drivers/crypto/fsl/jr.h @@ -34,6 +34,7 @@ #define JRNSLIODN_MASK 0x0fff0000 #define JRSLIODN_SHIFT 0 #define JRSLIODN_MASK 0x00000fff +#define JROWN_NS 0x00000008 #define JQ_DEQ_ERR -1 #define JQ_DEQ_TO_ERR -2 -- 2.7.4 _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
