* [PATCH 0/5] Switchtec MRPC DMA mode support @ 2018-11-15 9:43 Wesley Sheng 2018-11-15 6:03 ` Logan Gunthorpe ` (5 more replies) 0 siblings, 6 replies; 8+ messages in thread From: Wesley Sheng @ 2018-11-15 9:43 UTC (permalink / raw) To: kurt.schwemmer, logang, bhelgaas, linux-pci, linux-kernel Cc: wesleyshenggit, wesley.sheng Hi, Everyone, This patch series adds support for the Switchtec MRPC DMA mode. Switchtec switches supports 2 MRPC interaction modes: MRPC normal mode and MRPC DMA mode, a new feature in the latest firmware versions. MRPC normal mode requires the host to read the MRPC command status and output data. In MRPC DMA mode the command status and output data are pushed directly to host memory and issues an interrupt upon completion. The advantage of MRPC DMA mode is avoiding potential high latency response from the Memory Read TLP. Additionally, we've made the following changes: * Improve the efficiency of filling MRPC Input buffer by enabling write combining on MRPC region of BAR * Software workaround for delay responded Memory READ TLPs that access the BAR * And several bug fixes Regards, Wesley Boris Glimcher (1): switchtec: Set DMA coherent mask in Switchtec driver Joey Zhang (1): switchtec: A temporary variable should be used for the flags of switchtec_ioctl_event_ctl Kelvin Cao (2): switchtec: Remove immediate status check after submit a MRPC command switchtec: Improve MRPC efficiency by leveraging write combining Wesley Sheng (1): switchtec: MRPC DMA mode implementation drivers/pci/switch/switchtec.c | 154 ++++++++++++++++++++++++++++++++++++----- include/linux/switchtec.h | 16 +++++ 2 files changed, 153 insertions(+), 17 deletions(-) -- 2.7.4 ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 0/5] Switchtec MRPC DMA mode support 2018-11-15 9:43 [PATCH 0/5] Switchtec MRPC DMA mode support Wesley Sheng @ 2018-11-15 6:03 ` Logan Gunthorpe 2018-11-15 9:44 ` [PATCH 1/5] switchtec: Remove immediate status check after submit a MRPC command Wesley Sheng ` (4 subsequent siblings) 5 siblings, 0 replies; 8+ messages in thread From: Logan Gunthorpe @ 2018-11-15 6:03 UTC (permalink / raw) To: Wesley Sheng, kurt.schwemmer, bhelgaas, linux-pci, linux-kernel Cc: wesleyshenggit On 15/11/18 02:43 AM, Wesley Sheng wrote: > Hi, Everyone, > > This patch series adds support for the Switchtec MRPC DMA mode. I've reviewed this series from it's conception on github[1] and would like to see it land in the upstream driver, so for the entire series: Reviewed-by: Logan Gunthorpe <logang@deltatee.com> Thanks, Logan [1] https://github.com/Microsemi/switchtec-kernel ^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH 1/5] switchtec: Remove immediate status check after submit a MRPC command 2018-11-15 9:43 [PATCH 0/5] Switchtec MRPC DMA mode support Wesley Sheng 2018-11-15 6:03 ` Logan Gunthorpe @ 2018-11-15 9:44 ` Wesley Sheng 2018-11-15 9:44 ` [PATCH 2/5] switchtec: Set DMA coherent mask in Switchtec driver Wesley Sheng ` (3 subsequent siblings) 5 siblings, 0 replies; 8+ messages in thread From: Wesley Sheng @ 2018-11-15 9:44 UTC (permalink / raw) To: kurt.schwemmer, logang, bhelgaas, linux-pci, linux-kernel Cc: wesleyshenggit, wesley.sheng From: Kelvin Cao <kelvin.cao@microchip.com> After submitting a Firmware Download MRPC command, Switchtec firmware will delay Management EP BAR MemRd TLP responses by more than 10ms. This is a firmware limitation. Delayed MemRd completions are problem for systems with a low Completion Timeout (CTO). The current driver checks the MRPC status immediately after submitting an MRPC command, which results in the MemRd TLP that's affected by the above limitation. Remove the immediate status check and rely on the check after receiving an interrupt or timing out. This is only a software workaround to the READ issue and a proper fix of this should be done in firmware. Fixes: 080b47def5e5 ("MicroSemi Switchtec management interface driver") Signed-off-by: Kelvin Cao <kelvin.cao@microchip.com> Signed-off-by: Wesley Sheng <wesley.sheng@microchip.com> --- drivers/pci/switch/switchtec.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c index 54a8b30..d2bca2d 100644 --- a/drivers/pci/switch/switchtec.c +++ b/drivers/pci/switch/switchtec.c @@ -134,10 +134,6 @@ static void mrpc_cmd_submit(struct switchtec_dev *stdev) stuser->data, stuser->data_len); iowrite32(stuser->cmd, &stdev->mmio_mrpc->cmd); - stuser->status = ioread32(&stdev->mmio_mrpc->status); - if (stuser->status != SWITCHTEC_MRPC_STATUS_INPROGRESS) - mrpc_complete_cmd(stdev); - schedule_delayed_work(&stdev->mrpc_timeout, msecs_to_jiffies(500)); } -- 2.7.4 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH 2/5] switchtec: Set DMA coherent mask in Switchtec driver 2018-11-15 9:43 [PATCH 0/5] Switchtec MRPC DMA mode support Wesley Sheng 2018-11-15 6:03 ` Logan Gunthorpe 2018-11-15 9:44 ` [PATCH 1/5] switchtec: Remove immediate status check after submit a MRPC command Wesley Sheng @ 2018-11-15 9:44 ` Wesley Sheng 2018-11-15 9:44 ` [PATCH 3/5] switchtec: A temporary variable should be used for the flags of switchtec_ioctl_event_ctl Wesley Sheng ` (2 subsequent siblings) 5 siblings, 0 replies; 8+ messages in thread From: Wesley Sheng @ 2018-11-15 9:44 UTC (permalink / raw) To: kurt.schwemmer, logang, bhelgaas, linux-pci, linux-kernel Cc: wesleyshenggit, wesley.sheng From: Boris Glimcher <Boris.Glimcher@emc.com> Switchtec hardware supports 64-bit DMA, set the correct DMA mask. This allows the CMA to allocate larger buffers for memory windows. Signed-off-by: Boris Glimcher <Boris.Glimcher@emc.com> Signed-off-by: Wesley Sheng <wesley.sheng@microchip.com> --- drivers/pci/switch/switchtec.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c index d2bca2d..480107e 100644 --- a/drivers/pci/switch/switchtec.c +++ b/drivers/pci/switch/switchtec.c @@ -1237,6 +1237,10 @@ static int switchtec_init_pci(struct switchtec_dev *stdev, if (rc) return rc; + rc = dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(64)); + if (rc) + return rc; + pci_set_master(pdev); stdev->mmio = pcim_iomap_table(pdev)[0]; -- 2.7.4 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH 3/5] switchtec: A temporary variable should be used for the flags of switchtec_ioctl_event_ctl 2018-11-15 9:43 [PATCH 0/5] Switchtec MRPC DMA mode support Wesley Sheng ` (2 preceding siblings ...) 2018-11-15 9:44 ` [PATCH 2/5] switchtec: Set DMA coherent mask in Switchtec driver Wesley Sheng @ 2018-11-15 9:44 ` Wesley Sheng 2018-11-15 9:44 ` [PATCH 4/5] switchtec: Improve MRPC efficiency by leveraging write combining Wesley Sheng 2018-11-15 9:44 ` [PATCH 5/5] switchtec: MRPC DMA mode implementation Wesley Sheng 5 siblings, 0 replies; 8+ messages in thread From: Wesley Sheng @ 2018-11-15 9:44 UTC (permalink / raw) To: kurt.schwemmer, logang, bhelgaas, linux-pci, linux-kernel Cc: wesleyshenggit, wesley.sheng From: Joey Zhang <joey.zhang@microchip.com> For nr_idxs is larger than 1 switchtec_ioctl_event_ctl event flags will be used by each event indexes. In current implementation the event flags are overwritten by first call of the function event_ctl(). Preserve the event flag value with a temporary variable. Fixes: 52eabba5bcdb ("switchtec: Add IOCTLs to the Switchtec driver") Signed-off-by: Joey Zhang <joey.zhang@microchip.com> Signed-off-by: Wesley Sheng <wesley.sheng@microchip.com> --- drivers/pci/switch/switchtec.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c index 480107e..a908670 100644 --- a/drivers/pci/switch/switchtec.c +++ b/drivers/pci/switch/switchtec.c @@ -796,6 +796,7 @@ static int ioctl_event_ctl(struct switchtec_dev *stdev, { int ret; int nr_idxs; + unsigned int event_flags; struct switchtec_ioctl_event_ctl ctl; if (copy_from_user(&ctl, uctl, sizeof(ctl))) @@ -817,7 +818,9 @@ static int ioctl_event_ctl(struct switchtec_dev *stdev, else return -EINVAL; + event_flags = ctl.flags; for (ctl.index = 0; ctl.index < nr_idxs; ctl.index++) { + ctl.flags = event_flags; ret = event_ctl(stdev, &ctl); if (ret < 0) return ret; -- 2.7.4 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH 4/5] switchtec: Improve MRPC efficiency by leveraging write combining 2018-11-15 9:43 [PATCH 0/5] Switchtec MRPC DMA mode support Wesley Sheng ` (3 preceding siblings ...) 2018-11-15 9:44 ` [PATCH 3/5] switchtec: A temporary variable should be used for the flags of switchtec_ioctl_event_ctl Wesley Sheng @ 2018-11-15 9:44 ` Wesley Sheng 2018-11-15 9:44 ` [PATCH 5/5] switchtec: MRPC DMA mode implementation Wesley Sheng 5 siblings, 0 replies; 8+ messages in thread From: Wesley Sheng @ 2018-11-15 9:44 UTC (permalink / raw) To: kurt.schwemmer, logang, bhelgaas, linux-pci, linux-kernel Cc: wesleyshenggit, wesley.sheng From: Kelvin Cao <kelvin.cao@microchip.com> MRPC Input buffer is mostly memory without any side effects, thus we can improve the access time by enabling write combining on only this region of the BAR. In a few places, we still need to flush the WC buffer. To do this, we simply read from the Outbound Doorbell register seeing reads to this register are processed by low latency hardware. Signed-off-by: Kelvin Cao <kelvin.cao@microchip.com> Signed-off-by: Wesley Sheng <wesley.sheng@microchip.com> --- drivers/pci/switch/switchtec.c | 41 +++++++++++++++++++++++++++++++++++------ 1 file changed, 35 insertions(+), 6 deletions(-) diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c index a908670..0b8862b 100644 --- a/drivers/pci/switch/switchtec.c +++ b/drivers/pci/switch/switchtec.c @@ -113,6 +113,19 @@ static void stuser_set_state(struct switchtec_user *stuser, static void mrpc_complete_cmd(struct switchtec_dev *stdev); +static void flush_wc_buf(struct switchtec_dev *stdev) +{ + struct ntb_dbmsg_regs __iomem *mmio_dbmsg; + + /* + * odb (outbound doorbell) register is processed by low latency + * hardware and w/o side effect + */ + mmio_dbmsg = (void __iomem *)stdev->mmio_ntb + + SWITCHTEC_NTB_REG_DBMSG_OFFSET; + ioread32(&mmio_dbmsg->odb); +} + static void mrpc_cmd_submit(struct switchtec_dev *stdev) { /* requires the mrpc_mutex to already be held when called */ @@ -132,6 +145,7 @@ static void mrpc_cmd_submit(struct switchtec_dev *stdev) stdev->mrpc_busy = 1; memcpy_toio(&stdev->mmio_mrpc->input_data, stuser->data, stuser->data_len); + flush_wc_buf(stdev); iowrite32(stuser->cmd, &stdev->mmio_mrpc->cmd); schedule_delayed_work(&stdev->mrpc_timeout, @@ -1231,23 +1245,38 @@ static int switchtec_init_pci(struct switchtec_dev *stdev, struct pci_dev *pdev) { int rc; + void __iomem *map; + unsigned long res_start, res_len; rc = pcim_enable_device(pdev); if (rc) return rc; - rc = pcim_iomap_regions(pdev, 0x1, KBUILD_MODNAME); - if (rc) - return rc; - rc = dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(64)); if (rc) return rc; pci_set_master(pdev); - stdev->mmio = pcim_iomap_table(pdev)[0]; - stdev->mmio_mrpc = stdev->mmio + SWITCHTEC_GAS_MRPC_OFFSET; + res_start = pci_resource_start(pdev, 0); + res_len = pci_resource_len(pdev, 0); + + if (!devm_request_mem_region(&pdev->dev, res_start, + res_len, KBUILD_MODNAME)) + return -EBUSY; + + stdev->mmio_mrpc = devm_ioremap_wc(&pdev->dev, res_start, + SWITCHTEC_GAS_TOP_CFG_OFFSET); + if (!stdev->mmio_mrpc) + return -ENOMEM; + + map = devm_ioremap(&pdev->dev, + res_start + SWITCHTEC_GAS_TOP_CFG_OFFSET, + res_len - SWITCHTEC_GAS_TOP_CFG_OFFSET); + if (!map) + return -ENOMEM; + + stdev->mmio = map - SWITCHTEC_GAS_TOP_CFG_OFFSET; stdev->mmio_sw_event = stdev->mmio + SWITCHTEC_GAS_SW_EVENT_OFFSET; stdev->mmio_sys_info = stdev->mmio + SWITCHTEC_GAS_SYS_INFO_OFFSET; stdev->mmio_flash_info = stdev->mmio + SWITCHTEC_GAS_FLASH_INFO_OFFSET; -- 2.7.4 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH 5/5] switchtec: MRPC DMA mode implementation 2018-11-15 9:43 [PATCH 0/5] Switchtec MRPC DMA mode support Wesley Sheng ` (4 preceding siblings ...) 2018-11-15 9:44 ` [PATCH 4/5] switchtec: Improve MRPC efficiency by leveraging write combining Wesley Sheng @ 2018-11-15 9:44 ` Wesley Sheng 5 siblings, 0 replies; 8+ messages in thread From: Wesley Sheng @ 2018-11-15 9:44 UTC (permalink / raw) To: kurt.schwemmer, logang, bhelgaas, linux-pci, linux-kernel Cc: wesleyshenggit, wesley.sheng MRPC normal mode requires the host to read the MRPC command status and output data from BAR. This results in high latency responses from the Memory Read TLP and potential Completion Timeout (CTO). MRPC DMA mode implementation includes: Macro definitions for registers and data structures corresponding to MRPC DMA mode. Add module parameter use_dma_mrpc to select between MRPC DMA mode and MRPC normal mode. Add MRPC mode functionality to: * Retrieve MRPC DMA mode version * Allocate DMA buffer, ISR registration, and enable DMA function during initialization * Check MRPC execution status and collect execution results from DMA buffer * Release DMA buffer and disable DMA function when unloading module MRPC DMA mode is a new feature of firmware and the driver will fall back to MRPC normal mode if there is no support in the legacy firmware. Include <linux/io-64-nonatomic-lo-hi.h> so that readq/writeq is replaced by two readl/writel on systems that do not support it. Signed-off-by: Wesley Sheng <wesley.sheng@microchip.com> --- drivers/pci/switch/switchtec.c | 108 +++++++++++++++++++++++++++++++++++++---- include/linux/switchtec.h | 16 ++++++ 2 files changed, 114 insertions(+), 10 deletions(-) diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c index 0b8862b..6b726cb 100644 --- a/drivers/pci/switch/switchtec.c +++ b/drivers/pci/switch/switchtec.c @@ -13,7 +13,7 @@ #include <linux/uaccess.h> #include <linux/poll.h> #include <linux/wait.h> - +#include <linux/io-64-nonatomic-lo-hi.h> #include <linux/nospec.h> MODULE_DESCRIPTION("Microsemi Switchtec(tm) PCIe Management Driver"); @@ -25,6 +25,11 @@ static int max_devices = 16; module_param(max_devices, int, 0644); MODULE_PARM_DESC(max_devices, "max number of switchtec device instances"); +static bool use_dma_mrpc = 1; +module_param(use_dma_mrpc, bool, 0644); +MODULE_PARM_DESC(use_dma_mrpc, + "Enable the use of the DMA MRPC feature"); + static dev_t switchtec_devt; static DEFINE_IDA(switchtec_minor_ida); @@ -141,6 +146,11 @@ static void mrpc_cmd_submit(struct switchtec_dev *stdev) stuser = list_entry(stdev->mrpc_queue.next, struct switchtec_user, list); + if (stdev->dma_mrpc) { + stdev->dma_mrpc->status = SWITCHTEC_MRPC_STATUS_INPROGRESS; + memset(stdev->dma_mrpc->data, 0xFF, SWITCHTEC_MRPC_PAYLOAD_SIZE); + } + stuser_set_state(stuser, MRPC_RUNNING); stdev->mrpc_busy = 1; memcpy_toio(&stdev->mmio_mrpc->input_data, @@ -180,7 +190,11 @@ static void mrpc_complete_cmd(struct switchtec_dev *stdev) stuser = list_entry(stdev->mrpc_queue.next, struct switchtec_user, list); - stuser->status = ioread32(&stdev->mmio_mrpc->status); + if (stdev->dma_mrpc) + stuser->status = stdev->dma_mrpc->status; + else + stuser->status = ioread32(&stdev->mmio_mrpc->status); + if (stuser->status == SWITCHTEC_MRPC_STATUS_INPROGRESS) return; @@ -190,13 +204,19 @@ static void mrpc_complete_cmd(struct switchtec_dev *stdev) if (stuser->status != SWITCHTEC_MRPC_STATUS_DONE) goto out; - stuser->return_code = ioread32(&stdev->mmio_mrpc->ret_value); + if (stdev->dma_mrpc) + stuser->return_code = stdev->dma_mrpc->rtn_code; + else + stuser->return_code = ioread32(&stdev->mmio_mrpc->ret_value); if (stuser->return_code != 0) goto out; - memcpy_fromio(stuser->data, &stdev->mmio_mrpc->output_data, - stuser->read_len); - + if (stdev->dma_mrpc) + memcpy(stuser->data, &stdev->dma_mrpc->data, + stuser->read_len); + else + memcpy_fromio(stuser->data, &stdev->mmio_mrpc->output_data, + stuser->read_len); out: complete_all(&stuser->comp); list_del_init(&stuser->list); @@ -231,7 +251,10 @@ static void mrpc_timeout_work(struct work_struct *work) mutex_lock(&stdev->mrpc_mutex); - status = ioread32(&stdev->mmio_mrpc->status); + if (stdev->dma_mrpc) + status = stdev->dma_mrpc->status; + else + status = ioread32(&stdev->mmio_mrpc->status); if (status == SWITCHTEC_MRPC_STATUS_INPROGRESS) { schedule_delayed_work(&stdev->mrpc_timeout, msecs_to_jiffies(500)); @@ -239,7 +262,6 @@ static void mrpc_timeout_work(struct work_struct *work) } mrpc_complete_cmd(stdev); - out: mutex_unlock(&stdev->mrpc_mutex); } @@ -1030,10 +1052,24 @@ static void enable_link_state_events(struct switchtec_dev *stdev) } } +static void enable_dma_mrpc(struct switchtec_dev *stdev) +{ + writeq(stdev->dma_mrpc_dma_addr, &stdev->mmio_mrpc->dma_addr); + flush_wc_buf(stdev); + iowrite32(SWITCHTEC_DMA_MRPC_EN, &stdev->mmio_mrpc->dma_en); +} + static void stdev_release(struct device *dev) { struct switchtec_dev *stdev = to_stdev(dev); + if (stdev->dma_mrpc) { + iowrite32(0, &stdev->mmio_mrpc->dma_en); + flush_wc_buf(stdev); + writeq(0, &stdev->mmio_mrpc->dma_addr); + dma_free_coherent(&stdev->pdev->dev, sizeof(*stdev->dma_mrpc), + stdev->dma_mrpc, stdev->dma_mrpc_dma_addr); + } kfree(stdev); } @@ -1189,10 +1225,27 @@ static irqreturn_t switchtec_event_isr(int irq, void *dev) return ret; } + +static irqreturn_t switchtec_dma_mrpc_isr(int irq, void *dev) +{ + struct switchtec_dev *stdev = dev; + irqreturn_t ret = IRQ_NONE; + + iowrite32(SWITCHTEC_EVENT_CLEAR | + SWITCHTEC_EVENT_EN_IRQ, + &stdev->mmio_part_cfg->mrpc_comp_hdr); + schedule_work(&stdev->mrpc_work); + + ret = IRQ_HANDLED; + return ret; +} + static int switchtec_init_isr(struct switchtec_dev *stdev) { int nvecs; int event_irq; + int dma_mrpc_irq; + int rc; nvecs = pci_alloc_irq_vectors(stdev->pdev, 1, 4, PCI_IRQ_MSIX | PCI_IRQ_MSI); @@ -1207,9 +1260,29 @@ static int switchtec_init_isr(struct switchtec_dev *stdev) if (event_irq < 0) return event_irq; - return devm_request_irq(&stdev->pdev->dev, event_irq, + rc = devm_request_irq(&stdev->pdev->dev, event_irq, switchtec_event_isr, 0, KBUILD_MODNAME, stdev); + + if (rc) + return rc; + + if (!stdev->dma_mrpc) + return rc; + + dma_mrpc_irq = ioread32(&stdev->mmio_mrpc->dma_vector); + if (dma_mrpc_irq < 0 || dma_mrpc_irq >= nvecs) + return -EFAULT; + + dma_mrpc_irq = pci_irq_vector(stdev->pdev, dma_mrpc_irq); + if (dma_mrpc_irq < 0) + return dma_mrpc_irq; + + rc = devm_request_irq(&stdev->pdev->dev, dma_mrpc_irq, + switchtec_dma_mrpc_isr, 0, + KBUILD_MODNAME, stdev); + + return rc; } static void init_pff(struct switchtec_dev *stdev) @@ -1294,6 +1367,19 @@ static int switchtec_init_pci(struct switchtec_dev *stdev, pci_set_drvdata(pdev, stdev); + if (!use_dma_mrpc) + return 0; + + if (!(ioread32(&stdev->mmio_mrpc->dma_ver) ? true : false)) + return 0; + + stdev->dma_mrpc = dma_zalloc_coherent(&stdev->pdev->dev, + sizeof(*stdev->dma_mrpc), + &stdev->dma_mrpc_dma_addr, + GFP_KERNEL); + if (stdev->dma_mrpc == NULL) + return -ENOMEM; + return 0; } @@ -1325,6 +1411,9 @@ static int switchtec_pci_probe(struct pci_dev *pdev, &stdev->mmio_part_cfg->mrpc_comp_hdr); enable_link_state_events(stdev); + if (stdev->dma_mrpc) + enable_dma_mrpc(stdev); + rc = cdev_device_add(&stdev->cdev, &stdev->dev); if (rc) goto err_devadd; @@ -1350,7 +1439,6 @@ static void switchtec_pci_remove(struct pci_dev *pdev) cdev_device_del(&stdev->cdev, &stdev->dev); ida_simple_remove(&switchtec_minor_ida, MINOR(stdev->dev.devt)); dev_info(&stdev->dev, "unregistered.\n"); - stdev_kill(stdev); put_device(&stdev->dev); } diff --git a/include/linux/switchtec.h b/include/linux/switchtec.h index ab400af..eee0412 100644 --- a/include/linux/switchtec.h +++ b/include/linux/switchtec.h @@ -29,6 +29,7 @@ #define SWITCHTEC_EVENT_EN_IRQ BIT(3) #define SWITCHTEC_EVENT_FATAL BIT(4) +#define SWITCHTEC_DMA_MRPC_EN BIT(0) enum { SWITCHTEC_GAS_MRPC_OFFSET = 0x0000, SWITCHTEC_GAS_TOP_CFG_OFFSET = 0x1000, @@ -46,6 +47,10 @@ struct mrpc_regs { u32 cmd; u32 status; u32 ret_value; + u32 dma_en; + u64 dma_addr; + u32 dma_vector; + u32 dma_ver; } __packed; enum mrpc_status { @@ -342,6 +347,14 @@ struct pff_csr_regs { struct switchtec_ntb; +struct dma_mrpc_output { + u32 status; + u32 cmd_id; + u32 rtn_code; + u32 output_size; + u8 data[SWITCHTEC_MRPC_PAYLOAD_SIZE]; +}; + struct switchtec_dev { struct pci_dev *pdev; struct device dev; @@ -381,6 +394,9 @@ struct switchtec_dev { u8 link_event_count[SWITCHTEC_MAX_PFF_CSR]; struct switchtec_ntb *sndev; + + struct dma_mrpc_output *dma_mrpc; + dma_addr_t dma_mrpc_dma_addr; }; static inline struct switchtec_dev *to_stdev(struct device *dev) -- 2.7.4 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH 0/5] Switchtec MRPC DMA mode support @ 2018-12-10 9:12 Wesley Sheng 2018-12-10 9:12 ` [PATCH 4/5] switchtec: Improve MRPC efficiency by leveraging write combining Wesley Sheng 0 siblings, 1 reply; 8+ messages in thread From: Wesley Sheng @ 2018-12-10 9:12 UTC (permalink / raw) To: kurt.schwemmer, logang, bhelgaas, linux-pci, linux-kernel Cc: wesleyshenggit, wesley.sheng Hi, Everyone, This patch series adds support for the Switchtec MRPC DMA mode. Switchtec switches supports 2 MRPC interaction modes: MRPC normal mode and MRPC DMA mode, a new feature in the latest firmware versions. MRPC normal mode requires the host to read the MRPC command status and output data. In MRPC DMA mode the command status and output data are pushed directly to host memory and issues an interrupt upon completion. The advantage of MRPC DMA mode is avoiding potential high latency response from the Memory Read TLP. Additionally, we've made the following changes: * Improve the efficiency of filling MRPC Input buffer by enabling write combining on MRPC region of BAR * Software workaround for delay responded Memory READ TLPs that access the BAR * And several bug fixes Regards, Wesley -- Changed since v1: - It's a resend of v1 -- Boris Glimcher (1): switchtec: Set DMA coherent mask in Switchtec driver Joey Zhang (1): switchtec: A temporary variable should be used for the flags of switchtec_ioctl_event_ctl Kelvin Cao (2): switchtec: Remove immediate status check after submit a MRPC command switchtec: Improve MRPC efficiency by leveraging write combining Wesley Sheng (1): switchtec: MRPC DMA mode implementation drivers/pci/switch/switchtec.c | 154 ++++++++++++++++++++++++++++++++++++----- include/linux/switchtec.h | 16 +++++ 2 files changed, 153 insertions(+), 17 deletions(-) -- 2.7.4 ^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH 4/5] switchtec: Improve MRPC efficiency by leveraging write combining 2018-12-10 9:12 [PATCH 0/5] Switchtec MRPC DMA mode support Wesley Sheng @ 2018-12-10 9:12 ` Wesley Sheng 0 siblings, 0 replies; 8+ messages in thread From: Wesley Sheng @ 2018-12-10 9:12 UTC (permalink / raw) To: kurt.schwemmer, logang, bhelgaas, linux-pci, linux-kernel Cc: wesleyshenggit, wesley.sheng From: Kelvin Cao <kelvin.cao@microchip.com> MRPC Input buffer is mostly memory without any side effects, thus we can improve the access time by enabling write combining on only this region of the BAR. In a few places, we still need to flush the WC buffer. To do this, we simply read from the Outbound Doorbell register seeing reads to this register are processed by low latency hardware. Signed-off-by: Kelvin Cao <kelvin.cao@microchip.com> Signed-off-by: Wesley Sheng <wesley.sheng@microchip.com> Reviewed-by: Logan Gunthorpe <logang@deltatee.com> --- drivers/pci/switch/switchtec.c | 41 +++++++++++++++++++++++++++++++++++------ 1 file changed, 35 insertions(+), 6 deletions(-) diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c index a908670..0b8862b 100644 --- a/drivers/pci/switch/switchtec.c +++ b/drivers/pci/switch/switchtec.c @@ -113,6 +113,19 @@ static void stuser_set_state(struct switchtec_user *stuser, static void mrpc_complete_cmd(struct switchtec_dev *stdev); +static void flush_wc_buf(struct switchtec_dev *stdev) +{ + struct ntb_dbmsg_regs __iomem *mmio_dbmsg; + + /* + * odb (outbound doorbell) register is processed by low latency + * hardware and w/o side effect + */ + mmio_dbmsg = (void __iomem *)stdev->mmio_ntb + + SWITCHTEC_NTB_REG_DBMSG_OFFSET; + ioread32(&mmio_dbmsg->odb); +} + static void mrpc_cmd_submit(struct switchtec_dev *stdev) { /* requires the mrpc_mutex to already be held when called */ @@ -132,6 +145,7 @@ static void mrpc_cmd_submit(struct switchtec_dev *stdev) stdev->mrpc_busy = 1; memcpy_toio(&stdev->mmio_mrpc->input_data, stuser->data, stuser->data_len); + flush_wc_buf(stdev); iowrite32(stuser->cmd, &stdev->mmio_mrpc->cmd); schedule_delayed_work(&stdev->mrpc_timeout, @@ -1231,23 +1245,38 @@ static int switchtec_init_pci(struct switchtec_dev *stdev, struct pci_dev *pdev) { int rc; + void __iomem *map; + unsigned long res_start, res_len; rc = pcim_enable_device(pdev); if (rc) return rc; - rc = pcim_iomap_regions(pdev, 0x1, KBUILD_MODNAME); - if (rc) - return rc; - rc = dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(64)); if (rc) return rc; pci_set_master(pdev); - stdev->mmio = pcim_iomap_table(pdev)[0]; - stdev->mmio_mrpc = stdev->mmio + SWITCHTEC_GAS_MRPC_OFFSET; + res_start = pci_resource_start(pdev, 0); + res_len = pci_resource_len(pdev, 0); + + if (!devm_request_mem_region(&pdev->dev, res_start, + res_len, KBUILD_MODNAME)) + return -EBUSY; + + stdev->mmio_mrpc = devm_ioremap_wc(&pdev->dev, res_start, + SWITCHTEC_GAS_TOP_CFG_OFFSET); + if (!stdev->mmio_mrpc) + return -ENOMEM; + + map = devm_ioremap(&pdev->dev, + res_start + SWITCHTEC_GAS_TOP_CFG_OFFSET, + res_len - SWITCHTEC_GAS_TOP_CFG_OFFSET); + if (!map) + return -ENOMEM; + + stdev->mmio = map - SWITCHTEC_GAS_TOP_CFG_OFFSET; stdev->mmio_sw_event = stdev->mmio + SWITCHTEC_GAS_SW_EVENT_OFFSET; stdev->mmio_sys_info = stdev->mmio + SWITCHTEC_GAS_SYS_INFO_OFFSET; stdev->mmio_flash_info = stdev->mmio + SWITCHTEC_GAS_FLASH_INFO_OFFSET; -- 2.7.4 ^ permalink raw reply related [flat|nested] 8+ messages in thread
end of thread, other threads:[~2018-12-10 2:44 UTC | newest] Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2018-11-15 9:43 [PATCH 0/5] Switchtec MRPC DMA mode support Wesley Sheng 2018-11-15 6:03 ` Logan Gunthorpe 2018-11-15 9:44 ` [PATCH 1/5] switchtec: Remove immediate status check after submit a MRPC command Wesley Sheng 2018-11-15 9:44 ` [PATCH 2/5] switchtec: Set DMA coherent mask in Switchtec driver Wesley Sheng 2018-11-15 9:44 ` [PATCH 3/5] switchtec: A temporary variable should be used for the flags of switchtec_ioctl_event_ctl Wesley Sheng 2018-11-15 9:44 ` [PATCH 4/5] switchtec: Improve MRPC efficiency by leveraging write combining Wesley Sheng 2018-11-15 9:44 ` [PATCH 5/5] switchtec: MRPC DMA mode implementation Wesley Sheng 2018-12-10 9:12 [PATCH 0/5] Switchtec MRPC DMA mode support Wesley Sheng 2018-12-10 9:12 ` [PATCH 4/5] switchtec: Improve MRPC efficiency by leveraging write combining Wesley Sheng
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