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BHI/BHIe improvements for MHI power purposes

PATCH Superseded Bhaumik Bhatt 3 participants 14 messages May 5, 2021 – May 6, 2021

Subsystems (3)

v3 of 4 Superseded Latest is v4 →

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#0 lore raw

v3 cover BHI/BHIe improvements for MHI power purposes

This patch series improves the power up behavior by allowing MHI host driver to set BHI and/or BHIe offsets early on in the preparation phase and fail pre-power up if offsets are not found or not within a limited MMIO region. This also allows MHI host to clean up the offsets in the unprepare after power down phase.

Going forward, controllers will be required to specify a reg_len field which will be used to check whether the BHI/BHIe offsets are in range or not.

This series has been tested on X86_64 architecture with the PCI generic driver as controller and an SDX55 device.

v3:
-Added reviewed-by tags
-Updated order of reg_len in mhi_controller structure documentation

v2:
-Added reviewed-by tags
-Moved reg_len entry in mhi_controller structure to allow for a packed struct

Bhaumik Bhatt (6):
bus: mhi: core: Set BHI/BHIe offsets on power up preparation
bus: mhi: core: Set BHI and BHIe pointers to NULL in clean-up
bus: mhi: Add MMIO region length to controller structure
ath11k: set register access length for MHI driver
bus: mhi: pci_generic: Set register access length for MHI driver
bus: mhi: core: Add range checks for BHI and BHIe

 drivers/bus/mhi/core/init.c           | 58 +++++++++++++++++++++++------------
 drivers/bus/mhi/core/pm.c             | 28 +++--------------
 drivers/bus/mhi/pci_generic.c         |  1 +
 drivers/net/wireless/ath/ath11k/mhi.c |  1 +
 include/linux/mhi.h                   |  2 ++
 5 files changed, 47 insertions(+), 43 deletions(-)
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#1 lore raw

PATCH v3 1/6 bus: mhi: core: Set BHI/BHIe offsets on power up preparation

Set the BHI and/or BHIe offsets in mhi_prepare_for_power_up(), rearrange the function, and remove the equivalent from mhi_async_power_up(). This helps consolidate multiple checks in different parts of the driver and can help MHI fail early on before power up begins if the offsets are not read correctly.

---
 drivers/bus/mhi/core/init.c | 42 +++++++++++++++++++++++-------------------
 drivers/bus/mhi/core/pm.c   | 28 ++++------------------------
 2 files changed, 27 insertions(+), 43 deletions(-)
drivers/bus/mhi/core/init.c +23 -19
index c81b377..11c7a3d 100644
@@ -1063,7 +1063,7 @@ EXPORT_SYMBOL_GPL(mhi_free_controller);
 int mhi_prepare_for_power_up(struct mhi_controller *mhi_cntrl)
 {
 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
-	u32 bhie_off;
+	u32 bhi_off, bhie_off;
 	int ret;
 
 	mutex_lock(&mhi_cntrl->pm_mutex);
@@ -1072,29 +1072,36 @@ int mhi_prepare_for_power_up(struct mhi_controller *mhi_cntrl)
 	if (ret)
 		goto error_dev_ctxt;
 
-	/*
-	 * Allocate RDDM table if specified, this table is for debugging purpose
-	 */
-	if (mhi_cntrl->rddm_size) {
-		mhi_alloc_bhie_table(mhi_cntrl, &mhi_cntrl->rddm_image,
-				     mhi_cntrl->rddm_size);
+	ret = mhi_read_reg(mhi_cntrl, mhi_cntrl->regs, BHIOFF, &bhi_off);
+	if (ret) {
+		dev_err(dev, "Error getting BHI offset\n");
+		goto error_reg_offset;
+	}
+	mhi_cntrl->bhi = mhi_cntrl->regs + bhi_off;
 
-		/*
-		 * This controller supports RDDM, so we need to manually clear
-		 * BHIE RX registers since POR values are undefined.
-		 */
+	if (mhi_cntrl->fbc_download || mhi_cntrl->rddm_size) {
 		ret = mhi_read_reg(mhi_cntrl, mhi_cntrl->regs, BHIEOFF,
 				   &bhie_off);
 		if (ret) {
 			dev_err(dev, "Error getting BHIE offset\n");
-			goto bhie_error;
+			goto error_reg_offset;
 		}
-
 		mhi_cntrl->bhie = mhi_cntrl->regs + bhie_off;
+	}
+
+	if (mhi_cntrl->rddm_size) {
+		/*
+		 * This controller supports RDDM, so we need to manually clear
+		 * BHIE RX registers since POR values are undefined.
+		 */
 		memset_io(mhi_cntrl->bhie + BHIE_RXVECADDR_LOW_OFFS,
 			  0, BHIE_RXVECSTATUS_OFFS - BHIE_RXVECADDR_LOW_OFFS +
 			  4);
-
+		/*
+		 * Allocate RDDM table for debugging purpose if specified
+		 */
+		mhi_alloc_bhie_table(mhi_cntrl, &mhi_cntrl->rddm_image,
+				     mhi_cntrl->rddm_size);
 		if (mhi_cntrl->rddm_image)
 			mhi_rddm_prepare(mhi_cntrl, mhi_cntrl->rddm_image);
 	}
@@ -1103,11 +1110,8 @@ int mhi_prepare_for_power_up(struct mhi_controller *mhi_cntrl)
 
 	return 0;
 
-bhie_error:
-	if (mhi_cntrl->rddm_image) {
-		mhi_free_bhie_table(mhi_cntrl, mhi_cntrl->rddm_image);
-		mhi_cntrl->rddm_image = NULL;
-	}
+error_reg_offset:
+	mhi_deinit_dev_ctxt(mhi_cntrl);
 
 error_dev_ctxt:
 	mutex_unlock(&mhi_cntrl->pm_mutex);
drivers/bus/mhi/core/pm.c +4 -24
index e2e59a3..adf426c 100644
@@ -1066,28 +1066,8 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl)
 	if (ret)
 		goto error_setup_irq;
 
-	/* Setup BHI offset & INTVEC */
+	/* Setup BHI INTVEC */
 	write_lock_irq(&mhi_cntrl->pm_lock);
-	ret = mhi_read_reg(mhi_cntrl, mhi_cntrl->regs, BHIOFF, &val);
-	if (ret) {
-		write_unlock_irq(&mhi_cntrl->pm_lock);
-		goto error_bhi_offset;
-	}
-
-	mhi_cntrl->bhi = mhi_cntrl->regs + val;
-
-	/* Setup BHIE offset */
-	if (mhi_cntrl->fbc_download) {
-		ret = mhi_read_reg(mhi_cntrl, mhi_cntrl->regs, BHIEOFF, &val);
-		if (ret) {
-			write_unlock_irq(&mhi_cntrl->pm_lock);
-			dev_err(dev, "Error reading BHIE offset\n");
-			goto error_bhi_offset;
-		}
-
-		mhi_cntrl->bhie = mhi_cntrl->regs + val;
-	}
-
 	mhi_write_reg(mhi_cntrl, mhi_cntrl->bhi, BHI_INTVEC, 0);
 	mhi_cntrl->pm_state = MHI_PM_POR;
 	mhi_cntrl->ee = MHI_EE_MAX;
@@ -1098,7 +1078,7 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl)
 	if (!MHI_IN_PBL(current_ee) && current_ee != MHI_EE_AMSS) {
 		dev_err(dev, "Not a valid EE for power on\n");
 		ret = -EIO;
-		goto error_bhi_offset;
+		goto error_async_power_up;
 	}
 
 	state = mhi_get_mhi_state(mhi_cntrl);
@@ -1117,7 +1097,7 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl)
 		if (!ret) {
 			ret = -EIO;
 			dev_info(dev, "Failed to reset MHI due to syserr state\n");
-			goto error_bhi_offset;
+			goto error_async_power_up;
 		}
 
 		/*
@@ -1139,7 +1119,7 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl)
 
 	return 0;
 
-error_bhi_offset:
+error_async_power_up:
 	mhi_deinit_free_irq(mhi_cntrl);
 
 error_setup_irq:
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Reviewed-by on v3 1/6
#2 lore raw

Re: [PATCH v3 1/6] bus: mhi: core: Set BHI/BHIe offsets on power up preparation

Quoted 8 lines · Bhaumik Bhatt

Set the BHI and/or BHIe offsets in mhi_prepare_for_power_up(), rearrange the function, and remove the equivalent from mhi_async_power_up(). This helps consolidate multiple checks in different parts of the driver and can help MHI fail early on before power up begins if the offsets are not read correctly.

Signature · 2 lines
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#3 lore raw

PATCH v3 2/6 bus: mhi: core: Set BHI and BHIe pointers to NULL in clean-up

In reply to Bhaumik Bhatt

Set the BHI and BHIe pointers to NULL as part of clean-up. This makes sure that stale pointers are not accessed after powering MHI down.

---
 drivers/bus/mhi/core/init.c | 3 +++
 1 file changed, 3 insertions(+)
drivers/bus/mhi/core/init.c +3 -0
index 11c7a3d..1cc2f22 100644
@@ -1132,6 +1132,9 @@ void mhi_unprepare_after_power_down(struct mhi_controller *mhi_cntrl)
 		mhi_cntrl->rddm_image = NULL;
 	}
 
+	mhi_cntrl->bhi = NULL;
+	mhi_cntrl->bhie = NULL;
+
 	mhi_deinit_dev_ctxt(mhi_cntrl);
 }
 EXPORT_SYMBOL_GPL(mhi_unprepare_after_power_down);
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Reviewed-by on v3 2/6
#4 lore raw

Re: [PATCH v3 2/6] bus: mhi: core: Set BHI and BHIe pointers to NULL in clean-up

Quoted 7 lines · Bhaumik Bhatt

Set the BHI and BHIe pointers to NULL as part of clean-up. This makes sure that stale pointers are not accessed after powering MHI down.

Signature · 2 lines
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
#5 lore raw

PATCH v3 3/6 bus: mhi: Add MMIO region length to controller structure

In reply to Bhaumik Bhatt

Make controller driver specify the MMIO register region length for range checking of BHI or BHIe space. This can help validate that offsets are in acceptable memory region or not and avoid any boot-up issues due to BHI or BHIe memory accesses.

---
 include/linux/mhi.h | 2 ++
 1 file changed, 2 insertions(+)
include/linux/mhi.h +2 -0
index 944aa3a..9c347f5 100644
@@ -303,6 +303,7 @@ struct mhi_controller_config {
  * @rddm_size: RAM dump size that host should allocate for debugging purpose
  * @sbl_size: SBL image size downloaded through BHIe (optional)
  * @seg_len: BHIe vector size (optional)
+ * @reg_len: Length of the MHI MMIO region (required)
  * @fbc_image: Points to firmware image buffer
  * @rddm_image: Points to RAM dump buffer
  * @mhi_chan: Points to the channel configuration table
@@ -386,6 +387,7 @@ struct mhi_controller {
 	size_t rddm_size;
 	size_t sbl_size;
 	size_t seg_len;
+	size_t reg_len;
 	struct image_info *fbc_image;
 	struct image_info *rddm_image;
 	struct mhi_chan *mhi_chan;
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Reviewed-by on v3 3/6
#6 lore raw

Re: [PATCH v3 3/6] bus: mhi: Add MMIO region length to controller structure

Quoted 7 lines · Bhaumik Bhatt

Make controller driver specify the MMIO register region length for range checking of BHI or BHIe space. This can help validate that offsets are in acceptable memory region or not and avoid any boot-up issues due to BHI or BHIe memory accesses.

Signature · 2 lines
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#7 lore raw

PATCH v3 4/6 ath11k: set register access length for MHI driver

In reply to Bhaumik Bhatt

MHI driver requires register space length to add range checks and prevent memory region accesses outside of that for MMIO space. Set it before registering the MHI controller.

---
 drivers/net/wireless/ath/ath11k/mhi.c | 1 +
 1 file changed, 1 insertion(+)
drivers/net/wireless/ath/ath11k/mhi.c +1 -0
index 09858e5..c0f013c 100644
@@ -235,6 +235,7 @@ int ath11k_mhi_register(struct ath11k_pci *ab_pci)
 	mhi_ctrl->cntrl_dev = ab->dev;
 	mhi_ctrl->fw_image = ab_pci->amss_path;
 	mhi_ctrl->regs = ab->mem;
+	mhi_ctrl->reg_len = ab->mem_len;
 
 	ret = ath11k_mhi_get_msi(ab_pci);
 	if (ret) {
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Reviewed-by on v3 4/6
#8 lore raw

Re: [PATCH v3 4/6] ath11k: set register access length for MHI driver

Quoted 5 lines · Bhaumik Bhatt

MHI driver requires register space length to add range checks and prevent memory region accesses outside of that for MMIO space. Set it before registering the MHI controller.

Signature · 7 lines
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#9 lore raw

PATCH v3 5/6 bus: mhi: pci_generic: Set register access length for MHI driver

In reply to Bhaumik Bhatt

MHI driver requires register space length to add range checks and prevent memory region accesses outside of that for MMIO space. Set it from the PCI generic controller driver before registering the MHI controller.

---
 drivers/bus/mhi/pci_generic.c | 1 +
 1 file changed, 1 insertion(+)
drivers/bus/mhi/pci_generic.c +1 -0
index 7c810f0..fb7889f 100644
@@ -463,6 +463,7 @@ static int mhi_pci_claim(struct mhi_controller *mhi_cntrl,
 		return err;
 	}
 	mhi_cntrl->regs = pcim_iomap_table(pdev)[bar_num];
+	mhi_cntrl->reg_len = pci_resource_len(pdev, bar_num);
 
 	err = pci_set_dma_mask(pdev, dma_mask);
 	if (err) {
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Reviewed-by on v3 5/6
#10 lore raw

Re: [PATCH v3 5/6] bus: mhi: pci_generic: Set register access length for MHI driver

Quoted 6 lines · Bhaumik Bhatt

MHI driver requires register space length to add range checks and prevent memory region accesses outside of that for MMIO space. Set it from the PCI generic controller driver before registering the MHI controller.

Signature · 2 lines
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a Linux Foundation Collaborative Project
Reviewed-by on v3 5/6
#11 lore raw

Re: [PATCH v3 5/6] bus: mhi: pci_generic: Set register access length for MHI driver

In reply to Bhaumik Bhatt
Quoted 7 lines · Bhaumik Bhatt

MHI driver requires register space length to add range checks and prevent memory region accesses outside of that for MMIO space. Set it from the PCI generic controller driver before registering the MHI controller.

#12 lore raw

PATCH v3 6/6 bus: mhi: core: Add range checks for BHI and BHIe

In reply to Bhaumik Bhatt

When obtaining the BHI or BHIe offsets during the power up preparation phase, range checks are missing. These can help controller drivers avoid accessing any address outside of the MMIO region. Ensure that mhi_cntrl->reg_len is set before MHI registration as it is a required field and range checks will fail without it.

---
 drivers/bus/mhi/core/init.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)
drivers/bus/mhi/core/init.c +14 -1
index 1cc2f22..86ad06e 100644
@@ -885,7 +885,8 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl,
 	if (!mhi_cntrl || !mhi_cntrl->cntrl_dev || !mhi_cntrl->regs ||
 	    !mhi_cntrl->runtime_get || !mhi_cntrl->runtime_put ||
 	    !mhi_cntrl->status_cb || !mhi_cntrl->read_reg ||
-	    !mhi_cntrl->write_reg || !mhi_cntrl->nr_irqs || !mhi_cntrl->irq)
+	    !mhi_cntrl->write_reg || !mhi_cntrl->nr_irqs ||
+	    !mhi_cntrl->irq || !mhi_cntrl->reg_len)
 		return -EINVAL;
 
 	ret = parse_config(mhi_cntrl, config);
@@ -1077,6 +1078,12 @@ int mhi_prepare_for_power_up(struct mhi_controller *mhi_cntrl)
 		dev_err(dev, "Error getting BHI offset\n");
 		goto error_reg_offset;
 	}
+
+	if (bhi_off >= mhi_cntrl->reg_len) {
+		dev_err(dev, "BHI offset is out of range\n");
+		ret = -EINVAL;
+		goto error_reg_offset;
+	}
 	mhi_cntrl->bhi = mhi_cntrl->regs + bhi_off;
 
 	if (mhi_cntrl->fbc_download || mhi_cntrl->rddm_size) {
@@ -1086,6 +1093,12 @@ int mhi_prepare_for_power_up(struct mhi_controller *mhi_cntrl)
 			dev_err(dev, "Error getting BHIE offset\n");
 			goto error_reg_offset;
 		}
+
+		if (bhie_off >= mhi_cntrl->reg_len) {
+			dev_err(dev, "BHIe offset is out of range\n");
+			ret = -EINVAL;
+			goto error_reg_offset;
+		}
 		mhi_cntrl->bhie = mhi_cntrl->regs + bhie_off;
 	}
 
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#13 lore raw

Re: [PATCH v3 6/6] bus: mhi: core: Add range checks for BHI and BHIe

Hi Bhaumik,

Quoted 28 lines · Bhaumik Bhatt

When obtaining the BHI or BHIe offsets during the power up preparation phase, range checks are missing. These can help controller drivers avoid accessing any address outside of the MMIO region. Ensure that mhi_cntrl->reg_len is set before MHI registration as it is a required field and range checks will fail without it.

---
  drivers/bus/mhi/core/init.c | 15 ++++++++++++++-
  1 file changed, 14 insertions(+), 1 deletion(-)
drivers/bus/mhi/core/init.c +2 -1
index 1cc2f22..86ad06e 100644
@@ -885,7 +885,8 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl,
  	if (!mhi_cntrl || !mhi_cntrl->cntrl_dev || !mhi_cntrl->regs ||
  	    !mhi_cntrl->runtime_get || !mhi_cntrl->runtime_put ||
  	    !mhi_cntrl->status_cb || !mhi_cntrl->read_reg ||
-	    !mhi_cntrl->write_reg || !mhi_cntrl->nr_irqs || !mhi_cntrl->irq)
+	    !mhi_cntrl->write_reg || !mhi_cntrl->nr_irqs ||
+	    !mhi_cntrl->irq || !mhi_cntrl->reg_len)
  		return -EINVAL;
 
  	ret = parse_config(mhi_cntrl, config);

drivers/bus/mhi/core/init.c int mhi_prepare_for_power_up(struct mhi_controller *mhi_cntrl) · line 1083

Quoted 6 lines
drivers/bus/mhi/core/init.c +3 -0
@@ -1077,6 +1078,12 @@ int mhi_prepare_for_power_up(struct mhi_controller *mhi_cntrl)
  		dev_err(dev, "Error getting BHI offset\n");
  		goto error_reg_offset;
  	}
+
+	if (bhi_off >= mhi_cntrl->reg_len) {
+		dev_err(dev, "BHI offset is out of range\n");

Does is make sense to also log bhi_off and/or reg_len values in error if it helps in debugging

drivers/bus/mhi/core/init.c int mhi_prepare_for_power_up(struct mhi_controller *mhi_cntrl) · line 1098

Quoted 13 lines
drivers/bus/mhi/core/init.c +6 -0
+		ret = -EINVAL;
+		goto error_reg_offset;
+	}
  	mhi_cntrl->bhi = mhi_cntrl->regs + bhi_off;
 
  	if (mhi_cntrl->fbc_download || mhi_cntrl->rddm_size) {
@@ -1086,6 +1093,12 @@ int mhi_prepare_for_power_up(struct mhi_controller *mhi_cntrl)
  			dev_err(dev, "Error getting BHIE offset\n");
  			goto error_reg_offset;
  		}
+
+		if (bhie_off >= mhi_cntrl->reg_len) {
+			dev_err(dev, "BHIe offset is out of range\n");

Same comment as above

drivers/bus/mhi/core/init.c int mhi_prepare_for_power_up(struct mhi_controller *mhi_cntrl) · line 1104

Quoted 7 lines
drivers/bus/mhi/core/init.c +3 -0
+			ret = -EINVAL;
+			goto error_reg_offset;
+		}
  		mhi_cntrl->bhie = mhi_cntrl->regs + bhie_off;
  	}
 

Thanks,
Hemant

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