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Message-ID: <20190722232719.GT30636@minitux>
Date: Mon, 22 Jul 2019 16:27:19 -0700
From: Bjorn Andersson <bjorn.andersson@...aro.org>
To: Stephen Boyd <swboyd@...omium.org>
Cc: Andy Gross <agross@...nel.org>, linux-kernel@...r.kernel.org,
linux-arm-msm@...r.kernel.org,
Ian Jackson <ian.jackson@...rix.com>,
Julien Grall <julien.grall@....com>,
Avaneesh Kumar Dwivedi <akdwived@...eaurora.org>
Subject: Re: [PATCH 2/3] firmware: qcom_scm: Cleanup code in
qcom_scm_assign_mem()
On Fri 17 May 14:09 PDT 2019, Stephen Boyd wrote:
> There are some questionable coding styles in this function. It looks
> quite odd to deref a pointer with array indexing that only uses the
> first element. Also, destroying an input/output variable halfway through
> the function and then overwriting it on success is not clear. It's
> better to use a local variable and the kernel macros to step through
> each bit set in a bitmask and clearly show where outputs are set.
>
> Cc: Ian Jackson <ian.jackson@...rix.com>
> Cc: Julien Grall <julien.grall@....com>
> Cc: Bjorn Andersson <bjorn.andersson@...aro.org>
> Cc: Avaneesh Kumar Dwivedi <akdwived@...eaurora.org>
> Signed-off-by: Stephen Boyd <swboyd@...omium.org>
> ---
> drivers/firmware/qcom_scm.c | 34 ++++++++++++++++------------------
> include/linux/qcom_scm.h | 9 +++++----
> 2 files changed, 21 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
> index 0c63495cf269..153f13f72bac 100644
> --- a/drivers/firmware/qcom_scm.c
> +++ b/drivers/firmware/qcom_scm.c
> @@ -443,7 +443,8 @@ EXPORT_SYMBOL(qcom_scm_set_remote_state);
> */
> int qcom_scm_assign_mem(phys_addr_t mem_addr, size_t mem_sz,
> unsigned int *srcvm,
> - struct qcom_scm_vmperm *newvm, int dest_cnt)
> + const struct qcom_scm_vmperm *newvm,
> + unsigned int dest_cnt)
> {
> struct qcom_scm_current_perm_info *destvm;
> struct qcom_scm_mem_map_info *mem_to_map;
> @@ -458,11 +459,10 @@ int qcom_scm_assign_mem(phys_addr_t mem_addr, size_t mem_sz,
> int next_vm;
> __le32 *src;
> void *ptr;
> - int ret;
> - int len;
> - int i;
> + int ret, i, b;
> + unsigned long srcvm_bits = *srcvm;
>
> - src_sz = hweight_long(*srcvm) * sizeof(*src);
> + src_sz = hweight_long(srcvm_bits) * sizeof(*src);
> mem_to_map_sz = sizeof(*mem_to_map);
> dest_sz = dest_cnt * sizeof(*destvm);
> ptr_sz = ALIGN(src_sz, SZ_64) + ALIGN(mem_to_map_sz, SZ_64) +
> @@ -475,28 +475,26 @@ int qcom_scm_assign_mem(phys_addr_t mem_addr, size_t mem_sz,
>
> /* Fill source vmid detail */
> src = ptr;
> - len = hweight_long(*srcvm);
> - for (i = 0; i < len; i++) {
> - src[i] = cpu_to_le32(ffs(*srcvm) - 1);
> - *srcvm ^= 1 << (ffs(*srcvm) - 1);
> - }
> + i = 0;
> + for_each_set_bit(b, &srcvm_bits, sizeof(srcvm_bits))
The modem is sad that you only pass 8 here. Changed it to BITS_PER_LONG
to include the modem's permission bit and applied all three patches.
Thanks,
Bjorn
> + src[i++] = cpu_to_le32(b);
>
> /* Fill details of mem buff to map */
> mem_to_map = ptr + ALIGN(src_sz, SZ_64);
> mem_to_map_phys = ptr_phys + ALIGN(src_sz, SZ_64);
> - mem_to_map[0].mem_addr = cpu_to_le64(mem_addr);
> - mem_to_map[0].mem_size = cpu_to_le64(mem_sz);
> + mem_to_map->mem_addr = cpu_to_le64(mem_addr);
> + mem_to_map->mem_size = cpu_to_le64(mem_sz);
>
> next_vm = 0;
> /* Fill details of next vmid detail */
> destvm = ptr + ALIGN(mem_to_map_sz, SZ_64) + ALIGN(src_sz, SZ_64);
> dest_phys = ptr_phys + ALIGN(mem_to_map_sz, SZ_64) + ALIGN(src_sz, SZ_64);
> - for (i = 0; i < dest_cnt; i++) {
> - destvm[i].vmid = cpu_to_le32(newvm[i].vmid);
> - destvm[i].perm = cpu_to_le32(newvm[i].perm);
> - destvm[i].ctx = 0;
> - destvm[i].ctx_size = 0;
> - next_vm |= BIT(newvm[i].vmid);
> + for (i = 0; i < dest_cnt; i++, destvm++, newvm++) {
> + destvm->vmid = cpu_to_le32(newvm->vmid);
> + destvm->perm = cpu_to_le32(newvm->perm);
> + destvm->ctx = 0;
> + destvm->ctx_size = 0;
> + next_vm |= BIT(newvm->vmid);
> }
>
> ret = __qcom_scm_assign_mem(__scm->dev, mem_to_map_phys, mem_to_map_sz,
> diff --git a/include/linux/qcom_scm.h b/include/linux/qcom_scm.h
> index d0aecc04c54b..1d406403c843 100644
> --- a/include/linux/qcom_scm.h
> +++ b/include/linux/qcom_scm.h
> @@ -57,8 +57,9 @@ extern int qcom_scm_pas_mem_setup(u32 peripheral, phys_addr_t addr,
> extern int qcom_scm_pas_auth_and_reset(u32 peripheral);
> extern int qcom_scm_pas_shutdown(u32 peripheral);
> extern int qcom_scm_assign_mem(phys_addr_t mem_addr, size_t mem_sz,
> - unsigned int *src, struct qcom_scm_vmperm *newvm,
> - int dest_cnt);
> + unsigned int *src,
> + const struct qcom_scm_vmperm *newvm,
> + unsigned int dest_cnt);
> extern void qcom_scm_cpu_power_down(u32 flags);
> extern u32 qcom_scm_get_version(void);
> extern int qcom_scm_set_remote_state(u32 state, u32 id);
> @@ -95,8 +96,8 @@ qcom_scm_pas_auth_and_reset(u32 peripheral) { return -ENODEV; }
> static inline int qcom_scm_pas_shutdown(u32 peripheral) { return -ENODEV; }
> static inline int qcom_scm_assign_mem(phys_addr_t mem_addr, size_t mem_sz,
> unsigned int *src,
> - struct qcom_scm_vmperm *newvm,
> - int dest_cnt) { return -ENODEV; }
> + const struct qcom_scm_vmperm *newvm,
> + unsigned int dest_cnt) { return -ENODEV; }
> static inline void qcom_scm_cpu_power_down(u32 flags) {}
> static inline u32 qcom_scm_get_version(void) { return 0; }
> static inline u32
> --
> Sent by a computer through tubes
>
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