From 115f32512f13c0280161908e9de45a97a87673bb Mon Sep 17 00:00:00 2001 From: Manivannan Sadhasivam Date: Fri, 1 May 2020 00:35:50 +0530 Subject: bus: mhi: Fix parsing of mhi_flags With the current parsing of mhi_flags, the following statement always return false: eob = !!(flags & MHI_EOB); This is due to the fact that 'enum mhi_flags' starts with index 0 and we are using direct AND operation to extract each bit. Fix this by using BIT() macros for defining the flags so that the reset of the code need not be touched. Fixes: 189ff97cca53 ("bus: mhi: core: Add support for data transfer") Reported-by: Dan Carpenter Signed-off-by: Manivannan Sadhasivam Link: https://lore.kernel.org/r/20200430190555.32741-2-manivannan.sadhasivam@linaro.org Signed-off-by: Greg Kroah-Hartman --- include/linux/mhi.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'include') diff --git a/include/linux/mhi.h b/include/linux/mhi.h index ad1996001965..5642806360f3 100644 --- a/include/linux/mhi.h +++ b/include/linux/mhi.h @@ -53,9 +53,9 @@ enum mhi_callback { * @MHI_CHAIN: Linked transfer */ enum mhi_flags { - MHI_EOB, - MHI_EOT, - MHI_CHAIN, + MHI_EOB = BIT(0), + MHI_EOT = BIT(1), + MHI_CHAIN = BIT(2), }; /** -- cgit v1.2.3 From 85a087df4a719ebab940efa3c79625e68161f57b Mon Sep 17 00:00:00 2001 From: Jeffrey Hugo Date: Fri, 1 May 2020 00:35:52 +0530 Subject: bus: mhi: core: Remove link_status() callback If the MHI core detects invalid data due to a PCI read, it calls into the controller via link_status() to double check that the link is infact down. All in all, this is pretty pointless, and racy. There are no good reasons for this, and only drawbacks. Its pointless because chances are, the controller is going to do the same thing to determine if the link is down - attempt a PCI access and compare the result. This does not make the link status decision any smarter. Its racy because its possible that the link was down at the time of the MHI core access, but then recovered before the controller access. In this case, the controller will indicate the link is not down, and the MHI core will precede to use a bad value as the MHI core does not attempt to retry the access. Retrying the access in the MHI core is a bad idea because again, it is racy - what if the link is down again? Furthermore, there may be some higher level state associated with the link status, that is now invalid because the link went down. The only reason why the MHI core could see "invalid" data when doing a PCI access, that is actually valid, is if the register actually contained the PCI spec defined sentinel for an invalid access. In this case, it is arguable that the MHI implementation broken, and should be fixed, not worked around. Therefore, remove the link_status() callback before anyone attempts to implement it. Signed-off-by: Jeffrey Hugo Reviewed-by: Manivannan Sadhasivam Reviewed-by: Hemant Kumar Signed-off-by: Manivannan Sadhasivam Link: https://lore.kernel.org/r/20200430190555.32741-4-manivannan.sadhasivam@linaro.org Signed-off-by: Greg Kroah-Hartman --- drivers/bus/mhi/core/init.c | 6 ++---- drivers/bus/mhi/core/main.c | 5 ++--- include/linux/mhi.h | 2 -- 3 files changed, 4 insertions(+), 9 deletions(-) (limited to 'include') diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c index b38359c480ea..2af08d57ec28 100644 --- a/drivers/bus/mhi/core/init.c +++ b/drivers/bus/mhi/core/init.c @@ -812,10 +812,8 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl, if (!mhi_cntrl) return -EINVAL; - if (!mhi_cntrl->runtime_get || !mhi_cntrl->runtime_put) - return -EINVAL; - - if (!mhi_cntrl->status_cb || !mhi_cntrl->link_status) + if (!mhi_cntrl->runtime_get || !mhi_cntrl->runtime_put || + !mhi_cntrl->status_cb) return -EINVAL; ret = parse_config(mhi_cntrl, config); diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c index 55928feea0c9..f8401535e61a 100644 --- a/drivers/bus/mhi/core/main.c +++ b/drivers/bus/mhi/core/main.c @@ -20,9 +20,8 @@ int __must_check mhi_read_reg(struct mhi_controller *mhi_cntrl, { u32 tmp = readl(base + offset); - /* If there is any unexpected value, query the link status */ - if (PCI_INVALID_READ(tmp) && - mhi_cntrl->link_status(mhi_cntrl)) + /* If the value is invalid, the link is down */ + if (PCI_INVALID_READ(tmp)) return -EIO; *out = tmp; diff --git a/include/linux/mhi.h b/include/linux/mhi.h index 5642806360f3..c80ba559face 100644 --- a/include/linux/mhi.h +++ b/include/linux/mhi.h @@ -335,7 +335,6 @@ struct mhi_controller_config { * @syserr_worker: System error worker * @state_event: State change event * @status_cb: CB function to notify power states of the device (required) - * @link_status: CB function to query link status of the device (required) * @wake_get: CB function to assert device wake (optional) * @wake_put: CB function to de-assert device wake (optional) * @wake_toggle: CB function to assert and de-assert device wake (optional) @@ -417,7 +416,6 @@ struct mhi_controller { void (*status_cb)(struct mhi_controller *mhi_cntrl, enum mhi_callback cb); - int (*link_status)(struct mhi_controller *mhi_cntrl); void (*wake_get)(struct mhi_controller *mhi_cntrl, bool override); void (*wake_put)(struct mhi_controller *mhi_cntrl, bool override); void (*wake_toggle)(struct mhi_controller *mhi_cntrl); -- cgit v1.2.3 From 45723a44845c90c8e859fd0e2b0bb492322b5d0b Mon Sep 17 00:00:00 2001 From: Jeffrey Hugo Date: Fri, 1 May 2020 00:35:53 +0530 Subject: bus: mhi: core: Offload register accesses to the controller When reading or writing MHI registers, the core assumes that the physical link is a memory mapped PCI link. This assumption may not hold for all MHI devices. The controller knows what is the physical link (ie PCI, I2C, SPI, etc), and therefore knows the proper methods to access that link. The controller can also handle link specific error scenarios, such as reading -1 when the PCI link went down. Therefore, it is appropriate that the MHI core requests the controller to make register accesses on behalf of the core, which abstracts the core from link specifics, and end up removing an unnecessary assumption. Signed-off-by: Jeffrey Hugo Reviewed-by: Hemant Kumar Reviewed-by: Manivannan Sadhasivam Signed-off-by: Manivannan Sadhasivam Link: https://lore.kernel.org/r/20200430190555.32741-5-manivannan.sadhasivam@linaro.org Signed-off-by: Greg Kroah-Hartman --- drivers/bus/mhi/core/init.c | 3 ++- drivers/bus/mhi/core/internal.h | 3 --- drivers/bus/mhi/core/main.c | 12 ++---------- include/linux/mhi.h | 6 ++++++ 4 files changed, 10 insertions(+), 14 deletions(-) (limited to 'include') diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c index 2af08d57ec28..eb2ab058a01d 100644 --- a/drivers/bus/mhi/core/init.c +++ b/drivers/bus/mhi/core/init.c @@ -813,7 +813,8 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl, return -EINVAL; if (!mhi_cntrl->runtime_get || !mhi_cntrl->runtime_put || - !mhi_cntrl->status_cb) + !mhi_cntrl->status_cb || !mhi_cntrl->read_reg || + !mhi_cntrl->write_reg) return -EINVAL; ret = parse_config(mhi_cntrl, config); diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h index 5deadfaa053a..095d95bc0e37 100644 --- a/drivers/bus/mhi/core/internal.h +++ b/drivers/bus/mhi/core/internal.h @@ -11,9 +11,6 @@ extern struct bus_type mhi_bus_type; -/* MHI MMIO register mapping */ -#define PCI_INVALID_READ(val) (val == U32_MAX) - #define MHIREGLEN (0x0) #define MHIREGLEN_MHIREGLEN_MASK (0xFFFFFFFF) #define MHIREGLEN_MHIREGLEN_SHIFT (0) diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c index f8401535e61a..2aceb69f6ce8 100644 --- a/drivers/bus/mhi/core/main.c +++ b/drivers/bus/mhi/core/main.c @@ -18,15 +18,7 @@ int __must_check mhi_read_reg(struct mhi_controller *mhi_cntrl, void __iomem *base, u32 offset, u32 *out) { - u32 tmp = readl(base + offset); - - /* If the value is invalid, the link is down */ - if (PCI_INVALID_READ(tmp)) - return -EIO; - - *out = tmp; - - return 0; + return mhi_cntrl->read_reg(mhi_cntrl, base + offset, out); } int __must_check mhi_read_reg_field(struct mhi_controller *mhi_cntrl, @@ -48,7 +40,7 @@ int __must_check mhi_read_reg_field(struct mhi_controller *mhi_cntrl, void mhi_write_reg(struct mhi_controller *mhi_cntrl, void __iomem *base, u32 offset, u32 val) { - writel(val, base + offset); + mhi_cntrl->write_reg(mhi_cntrl, base + offset, val); } void mhi_write_reg_field(struct mhi_controller *mhi_cntrl, void __iomem *base, diff --git a/include/linux/mhi.h b/include/linux/mhi.h index c80ba559face..84a6c9e72f52 100644 --- a/include/linux/mhi.h +++ b/include/linux/mhi.h @@ -342,6 +342,8 @@ struct mhi_controller_config { * @runtimet_put: CB function to decrement pm usage (required) * @map_single: CB function to create TRE buffer * @unmap_single: CB function to destroy TRE buffer + * @read_reg: Read a MHI register via the physical link (required) + * @write_reg: Write a MHI register via the physical link (required) * @buffer_len: Bounce buffer length * @bounce_buf: Use of bounce buffer * @fbc_download: MHI host needs to do complete image transfer (optional) @@ -425,6 +427,10 @@ struct mhi_controller { struct mhi_buf_info *buf); void (*unmap_single)(struct mhi_controller *mhi_cntrl, struct mhi_buf_info *buf); + int (*read_reg)(struct mhi_controller *mhi_cntrl, void __iomem *addr, + u32 *out); + void (*write_reg)(struct mhi_controller *mhi_cntrl, void __iomem *addr, + u32 val); size_t buffer_len; bool bounce_buf; -- cgit v1.2.3 From af2e58818082ac0db29539444ca17eb1e77f6000 Mon Sep 17 00:00:00 2001 From: Jeffrey Hugo Date: Fri, 1 May 2020 00:35:54 +0530 Subject: bus: mhi: core: Fix typo in comment There is a typo - "runtimet" should be "runtime". Fix it. Signed-off-by: Jeffrey Hugo Reviewed-by: Hemant Kumar Reviewed-by: Manivannan Sadhasivam Signed-off-by: Manivannan Sadhasivam Link: https://lore.kernel.org/r/20200430190555.32741-6-manivannan.sadhasivam@linaro.org Signed-off-by: Greg Kroah-Hartman --- include/linux/mhi.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/mhi.h b/include/linux/mhi.h index 84a6c9e72f52..3d7c3c26eeb9 100644 --- a/include/linux/mhi.h +++ b/include/linux/mhi.h @@ -339,7 +339,7 @@ struct mhi_controller_config { * @wake_put: CB function to de-assert device wake (optional) * @wake_toggle: CB function to assert and de-assert device wake (optional) * @runtime_get: CB function to controller runtime resume (required) - * @runtimet_put: CB function to decrement pm usage (required) + * @runtime_put: CB function to decrement pm usage (required) * @map_single: CB function to create TRE buffer * @unmap_single: CB function to destroy TRE buffer * @read_reg: Read a MHI register via the physical link (required) -- cgit v1.2.3