| From d8714bf1d966577e73aa48e6a2c1f9da5105d1aa Mon Sep 17 00:00:00 2001 |
| From: Alan Tull <atull@kernel.org> |
| Date: Wed, 15 Nov 2017 14:20:13 -0600 |
| Subject: [PATCH 1662/1795] fpga: mgr: separate getting/locking FPGA manager |
| |
| Previously when the user gets a FPGA manager, it was locked |
| and nobody else could use it for programming. |
| |
| This commit makes it straightforward to save a reference to an |
| FPGA manager and only lock it when programming the FPGA. |
| |
| Add functions that get an FPGA manager's mutex for exclusive use: |
| * fpga_mgr_lock |
| * fpga_mgr_unlock |
| |
| The following functions no longer lock an FPGA manager's mutex: |
| * of_fpga_mgr_get |
| * fpga_mgr_get |
| * fpga_mgr_put |
| |
| Signed-off-by: Alan Tull <atull@kernel.org> |
| Acked-by: Moritz Fischer <mdf@kernel.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| (cherry picked from commit ebf877a51ad7b65e4ab024f021b60a4f7928864a) |
| Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> |
| --- |
| Documentation/fpga/fpga-mgr.txt | 35 ++++++++++++++++------ |
| drivers/fpga/fpga-mgr.c | 52 +++++++++++++++++++++++---------- |
| drivers/fpga/fpga-region.c | 14 +++++++-- |
| include/linux/fpga/fpga-mgr.h | 3 ++ |
| 4 files changed, 77 insertions(+), 27 deletions(-) |
| |
| diff --git a/Documentation/fpga/fpga-mgr.txt b/Documentation/fpga/fpga-mgr.txt |
| index 6ebc714f4b03..cc6413ed6fc9 100644 |
| --- a/Documentation/fpga/fpga-mgr.txt |
| +++ b/Documentation/fpga/fpga-mgr.txt |
| @@ -48,8 +48,20 @@ To get/put a reference to a FPGA manager: |
| struct fpga_manager *fpga_mgr_get(struct device *dev); |
| void fpga_mgr_put(struct fpga_manager *mgr); |
| |
| -Given a DT node or device, get an exclusive reference to a FPGA manager. |
| -fpga_mgr_put releases the reference. |
| +Given a DT node or device, get a reference to a FPGA manager. This pointer |
| +can be saved until you are ready to program the FPGA. fpga_mgr_put releases |
| +the reference. |
| + |
| + |
| +To get exclusive control of a FPGA manager: |
| +------------------------------------------- |
| + |
| + int fpga_mgr_lock(struct fpga_manager *mgr); |
| + void fpga_mgr_unlock(struct fpga_manager *mgr); |
| + |
| +The user should call fpga_mgr_lock and verify that it returns 0 before |
| +attempting to program the FPGA. Likewise, the user should call |
| +fpga_mgr_unlock when done programming the FPGA. |
| |
| |
| To register or unregister the low level FPGA-specific driver: |
| @@ -67,13 +79,21 @@ device." |
| |
| How to write an image buffer to a supported FPGA |
| ================================================ |
| -/* Include to get the API */ |
| #include <linux/fpga/fpga-mgr.h> |
| |
| struct fpga_manager *mgr; |
| struct fpga_image_info *info; |
| int ret; |
| |
| +/* |
| + * Get a reference to FPGA manager. The manager is not locked, so you can |
| + * hold onto this reference without it preventing programming. |
| + * |
| + * This example uses the device node of the manager. Alternatively, use |
| + * fpga_mgr_get(dev) instead if you have the device. |
| + */ |
| +mgr = of_fpga_mgr_get(mgr_node); |
| + |
| /* struct with information about the FPGA image to program. */ |
| info = fpga_image_info_alloc(dev); |
| |
| @@ -99,17 +119,14 @@ if (image is in a scatter gather table) { |
| |
| } |
| |
| -/* |
| - * Get a reference to FPGA manager. This example uses the device node of the |
| - * manager. You could use fpga_mgr_get() instead if you have the device instead |
| - * of the device node. |
| - */ |
| -mgr = of_fpga_mgr_get(mgr_node); |
| +/* Get exclusive control of FPGA manager */ |
| +ret = fpga_mgr_lock(mgr); |
| |
| /* Load the buffer to the FPGA */ |
| ret = fpga_mgr_buf_load(mgr, &info, buf, count); |
| |
| /* Release the FPGA manager */ |
| +fpga_mgr_unlock(mgr); |
| fpga_mgr_put(mgr); |
| |
| /* Deallocate the image info if you're done with it */ |
| diff --git a/drivers/fpga/fpga-mgr.c b/drivers/fpga/fpga-mgr.c |
| index a8dd54945470..d27e8d2a149c 100644 |
| --- a/drivers/fpga/fpga-mgr.c |
| +++ b/drivers/fpga/fpga-mgr.c |
| @@ -410,28 +410,19 @@ ATTRIBUTE_GROUPS(fpga_mgr); |
| static struct fpga_manager *__fpga_mgr_get(struct device *dev) |
| { |
| struct fpga_manager *mgr; |
| - int ret = -ENODEV; |
| |
| mgr = to_fpga_manager(dev); |
| if (!mgr) |
| goto err_dev; |
| |
| - /* Get exclusive use of fpga manager */ |
| - if (!mutex_trylock(&mgr->ref_mutex)) { |
| - ret = -EBUSY; |
| - goto err_dev; |
| - } |
| - |
| if (!try_module_get(dev->parent->driver->owner)) |
| - goto err_ll_mod; |
| + goto err_dev; |
| |
| return mgr; |
| |
| -err_ll_mod: |
| - mutex_unlock(&mgr->ref_mutex); |
| err_dev: |
| put_device(dev); |
| - return ERR_PTR(ret); |
| + return ERR_PTR(-ENODEV); |
| } |
| |
| static int fpga_mgr_dev_match(struct device *dev, const void *data) |
| @@ -440,10 +431,10 @@ static int fpga_mgr_dev_match(struct device *dev, const void *data) |
| } |
| |
| /** |
| - * fpga_mgr_get - get an exclusive reference to a fpga mgr |
| + * fpga_mgr_get - get a reference to a fpga mgr |
| * @dev: parent device that fpga mgr was registered with |
| * |
| - * Given a device, get an exclusive reference to a fpga mgr. |
| + * Given a device, get a reference to a fpga mgr. |
| * |
| * Return: fpga manager struct or IS_ERR() condition containing error code. |
| */ |
| @@ -464,10 +455,10 @@ static int fpga_mgr_of_node_match(struct device *dev, const void *data) |
| } |
| |
| /** |
| - * of_fpga_mgr_get - get an exclusive reference to a fpga mgr |
| + * of_fpga_mgr_get - get a reference to a fpga mgr |
| * @node: device node |
| * |
| - * Given a device node, get an exclusive reference to a fpga mgr. |
| + * Given a device node, get a reference to a fpga mgr. |
| * |
| * Return: fpga manager struct or IS_ERR() condition containing error code. |
| */ |
| @@ -491,11 +482,40 @@ EXPORT_SYMBOL_GPL(of_fpga_mgr_get); |
| void fpga_mgr_put(struct fpga_manager *mgr) |
| { |
| module_put(mgr->dev.parent->driver->owner); |
| - mutex_unlock(&mgr->ref_mutex); |
| put_device(&mgr->dev); |
| } |
| EXPORT_SYMBOL_GPL(fpga_mgr_put); |
| |
| +/** |
| + * fpga_mgr_lock - Lock FPGA manager for exclusive use |
| + * @mgr: fpga manager |
| + * |
| + * Given a pointer to FPGA Manager (from fpga_mgr_get() or |
| + * of_fpga_mgr_put()) attempt to get the mutex. |
| + * |
| + * Return: 0 for success or -EBUSY |
| + */ |
| +int fpga_mgr_lock(struct fpga_manager *mgr) |
| +{ |
| + if (!mutex_trylock(&mgr->ref_mutex)) { |
| + dev_err(&mgr->dev, "FPGA manager is in use.\n"); |
| + return -EBUSY; |
| + } |
| + |
| + return 0; |
| +} |
| +EXPORT_SYMBOL_GPL(fpga_mgr_lock); |
| + |
| +/** |
| + * fpga_mgr_unlock - Unlock FPGA manager |
| + * @mgr: fpga manager |
| + */ |
| +void fpga_mgr_unlock(struct fpga_manager *mgr) |
| +{ |
| + mutex_unlock(&mgr->ref_mutex); |
| +} |
| +EXPORT_SYMBOL_GPL(fpga_mgr_unlock); |
| + |
| /** |
| * fpga_mgr_register - register a low level fpga manager driver |
| * @dev: fpga manager device from pdev |
| diff --git a/drivers/fpga/fpga-region.c b/drivers/fpga/fpga-region.c |
| index 5c107ac39796..e8daac3e3d37 100644 |
| --- a/drivers/fpga/fpga-region.c |
| +++ b/drivers/fpga/fpga-region.c |
| @@ -125,7 +125,7 @@ static void fpga_region_put(struct fpga_region *region) |
| } |
| |
| /** |
| - * fpga_region_get_manager - get exclusive reference for FPGA manager |
| + * fpga_region_get_manager - get reference for FPGA manager |
| * @region: FPGA region |
| * |
| * Get FPGA Manager from "fpga-mgr" property or from ancestor region. |
| @@ -240,6 +240,7 @@ static int fpga_region_get_bridges(struct fpga_region *region, |
| static int fpga_region_program_fpga(struct fpga_region *region, |
| struct device_node *overlay) |
| { |
| + struct device *dev = ®ion->dev; |
| struct fpga_manager *mgr; |
| int ret; |
| |
| @@ -256,10 +257,16 @@ static int fpga_region_program_fpga(struct fpga_region *region, |
| goto err_put_region; |
| } |
| |
| + ret = fpga_mgr_lock(mgr); |
| + if (ret) { |
| + dev_err(dev, "FPGA manager is busy\n"); |
| + goto err_put_mgr; |
| + } |
| + |
| ret = fpga_region_get_bridges(region, overlay); |
| if (ret) { |
| pr_err("failed to get fpga region bridges\n"); |
| - goto err_put_mgr; |
| + goto err_unlock_mgr; |
| } |
| |
| ret = fpga_bridges_disable(®ion->bridge_list); |
| @@ -280,6 +287,7 @@ static int fpga_region_program_fpga(struct fpga_region *region, |
| goto err_put_br; |
| } |
| |
| + fpga_mgr_unlock(mgr); |
| fpga_mgr_put(mgr); |
| fpga_region_put(region); |
| |
| @@ -287,6 +295,8 @@ static int fpga_region_program_fpga(struct fpga_region *region, |
| |
| err_put_br: |
| fpga_bridges_put(®ion->bridge_list); |
| +err_unlock_mgr: |
| + fpga_mgr_unlock(mgr); |
| err_put_mgr: |
| fpga_mgr_put(mgr); |
| err_put_region: |
| diff --git a/include/linux/fpga/fpga-mgr.h b/include/linux/fpga/fpga-mgr.h |
| index 6b791348023b..cb5615c87504 100644 |
| --- a/include/linux/fpga/fpga-mgr.h |
| +++ b/include/linux/fpga/fpga-mgr.h |
| @@ -155,6 +155,9 @@ void fpga_image_info_free(struct fpga_image_info *info); |
| |
| int fpga_mgr_load(struct fpga_manager *mgr, struct fpga_image_info *info); |
| |
| +int fpga_mgr_lock(struct fpga_manager *mgr); |
| +void fpga_mgr_unlock(struct fpga_manager *mgr); |
| + |
| struct fpga_manager *of_fpga_mgr_get(struct device_node *node); |
| |
| struct fpga_manager *fpga_mgr_get(struct device *dev); |
| -- |
| 2.19.0 |
| |