1 /* SPDX-License-Identifier: GPL-2.0+ */
2 #include <linux/init.h>
3 #include <linux/module.h>
4 #include <linux/types.h>
6 #include <linux/export.h>
7 #include <linux/slab.h>
8 #include <linux/platform_device.h>
10 #include <linux/rwsem.h>
11 #include "kpc_dma_driver.h"
13 /********** IRQ Handlers **********/
15 irqreturn_t ndd_irq_handler(int irq, void *dev_id)
17 struct kpc_dma_device *ldev = (struct kpc_dma_device *)dev_id;
19 if ((GetEngineControl(ldev) & ENG_CTL_IRQ_ACTIVE) || (ldev->desc_completed->MyDMAAddr != GetEngineCompletePtr(ldev)))
20 schedule_work(&ldev->irq_work);
26 void ndd_irq_worker(struct work_struct *ws)
28 struct kpc_dma_descriptor *cur;
29 struct kpc_dma_device *eng = container_of(ws, struct kpc_dma_device, irq_work);
33 if (GetEngineCompletePtr(eng) == 0)
36 if (eng->desc_completed->MyDMAAddr == GetEngineCompletePtr(eng))
39 cur = eng->desc_completed;
42 dev_dbg(&eng->pldev->dev, "Handling completed descriptor %p (acd = %p)\n", cur, cur->acd);
43 BUG_ON(cur == eng->desc_next); // Ordering failure.
45 if (cur->DescControlFlags & DMA_DESC_CTL_SOP) {
46 eng->accumulated_bytes = 0;
47 eng->accumulated_flags = 0;
50 eng->accumulated_bytes += cur->DescByteCount;
51 if (cur->DescStatusFlags & DMA_DESC_STS_ERROR)
52 eng->accumulated_flags |= ACD_FLAG_ENG_ACCUM_ERROR;
54 if (cur->DescStatusFlags & DMA_DESC_STS_SHORT)
55 eng->accumulated_flags |= ACD_FLAG_ENG_ACCUM_SHORT;
57 if (cur->DescControlFlags & DMA_DESC_CTL_EOP) {
59 transfer_complete_cb(cur->acd, eng->accumulated_bytes, eng->accumulated_flags | ACD_FLAG_DONE);
62 eng->desc_completed = cur;
63 } while (cur->MyDMAAddr != GetEngineCompletePtr(eng));
66 SetClearEngineControl(eng, ENG_CTL_IRQ_ACTIVE, 0);
71 /********** DMA Engine Init/Teardown **********/
72 void start_dma_engine(struct kpc_dma_device *eng)
74 eng->desc_next = eng->desc_pool_first;
75 eng->desc_completed = eng->desc_pool_last;
77 // Setup the engine pointer registers
78 SetEngineNextPtr(eng, eng->desc_pool_first);
79 SetEngineSWPtr(eng, eng->desc_pool_first);
80 ClearEngineCompletePtr(eng);
82 WriteEngineControl(eng, ENG_CTL_DMA_ENABLE | ENG_CTL_IRQ_ENABLE);
85 int setup_dma_engine(struct kpc_dma_device *eng, u32 desc_cnt)
88 struct kpc_dma_descriptor *cur;
89 struct kpc_dma_descriptor *next;
90 dma_addr_t next_handle;
91 dma_addr_t head_handle;
95 dev_dbg(&eng->pldev->dev, "Setting up DMA engine [%p]\n", eng);
97 caps = GetEngineCapabilities(eng);
99 if (WARN(!(caps & ENG_CAP_PRESENT), "%s() called for DMA Engine at %p which isn't present in hardware!\n", __func__, eng))
102 if (caps & ENG_CAP_DIRECTION) {
103 eng->dir = DMA_FROM_DEVICE;
105 eng->dir = DMA_TO_DEVICE;
108 eng->desc_pool_cnt = desc_cnt;
109 eng->desc_pool = dma_pool_create("KPC DMA Descriptors", &eng->pldev->dev, sizeof(struct kpc_dma_descriptor), DMA_DESC_ALIGNMENT, 4096);
111 eng->desc_pool_first = dma_pool_alloc(eng->desc_pool, GFP_KERNEL | GFP_DMA, &head_handle);
112 if (!eng->desc_pool_first) {
113 dev_err(&eng->pldev->dev, "%s: couldn't allocate desc_pool_first!\n", __func__);
114 dma_pool_destroy(eng->desc_pool);
118 eng->desc_pool_first->MyDMAAddr = head_handle;
119 clear_desc(eng->desc_pool_first);
121 cur = eng->desc_pool_first;
122 for (i = 1 ; i < eng->desc_pool_cnt ; i++) {
123 next = dma_pool_alloc(eng->desc_pool, GFP_KERNEL | GFP_DMA, &next_handle);
128 next->MyDMAAddr = next_handle;
130 cur->DescNextDescPtr = next_handle;
136 // Link the last descriptor back to the first, so it's a circular linked list
137 cur->Next = eng->desc_pool_first;
138 cur->DescNextDescPtr = eng->desc_pool_first->MyDMAAddr;
140 eng->desc_pool_last = cur;
141 eng->desc_completed = eng->desc_pool_last;
144 INIT_WORK(&eng->irq_work, ndd_irq_worker);
147 rv = request_irq(eng->irq, ndd_irq_handler, IRQF_SHARED, KP_DRIVER_NAME_DMA_CONTROLLER, eng);
149 dev_err(&eng->pldev->dev, "%s: failed to request_irq: %d\n", __func__, rv);
153 // Turn on the engine!
154 start_dma_engine(eng);
160 void stop_dma_engine(struct kpc_dma_device *eng)
162 unsigned long timeout;
164 dev_dbg(&eng->pldev->dev, "Destroying DMA engine [%p]\n", eng);
166 // Disable the descriptor engine
167 WriteEngineControl(eng, 0);
169 // Wait for descriptor engine to finish current operaion
170 timeout = jiffies + (HZ / 2);
171 while (GetEngineControl(eng) & ENG_CTL_DMA_RUNNING) {
172 if (time_after(jiffies, timeout)) {
173 dev_crit(&eng->pldev->dev, "DMA_RUNNING still asserted!\n");
179 WriteEngineControl(eng, ENG_CTL_DMA_RESET_REQUEST);
181 // Wait for reset request to be processed
182 timeout = jiffies + (HZ / 2);
183 while (GetEngineControl(eng) & (ENG_CTL_DMA_RUNNING | ENG_CTL_DMA_RESET_REQUEST)) {
184 if (time_after(jiffies, timeout)) {
185 dev_crit(&eng->pldev->dev, "ENG_CTL_DMA_RESET_REQUEST still asserted!\n");
191 WriteEngineControl(eng, ENG_CTL_DMA_RESET);
193 // And wait for reset to complete
194 timeout = jiffies + (HZ / 2);
195 while (GetEngineControl(eng) & ENG_CTL_DMA_RESET) {
196 if (time_after(jiffies, timeout)) {
197 dev_crit(&eng->pldev->dev, "DMA_RESET still asserted!\n");
202 // Clear any persistent bits just to make sure there is no residue from the reset
203 SetClearEngineControl(eng, (ENG_CTL_IRQ_ACTIVE | ENG_CTL_DESC_COMPLETE | ENG_CTL_DESC_ALIGN_ERR | ENG_CTL_DESC_FETCH_ERR | ENG_CTL_SW_ABORT_ERR | ENG_CTL_DESC_CHAIN_END | ENG_CTL_DMA_WAITING_PERSIST), 0);
205 // Reset performance counters
207 // Completely disable the engine
208 WriteEngineControl(eng, 0);
211 void destroy_dma_engine(struct kpc_dma_device *eng)
213 struct kpc_dma_descriptor *cur;
214 dma_addr_t cur_handle;
217 stop_dma_engine(eng);
219 cur = eng->desc_pool_first;
220 cur_handle = eng->desc_pool_first->MyDMAAddr;
222 for (i = 0 ; i < eng->desc_pool_cnt ; i++) {
223 struct kpc_dma_descriptor *next = cur->Next;
224 dma_addr_t next_handle = cur->DescNextDescPtr;
226 dma_pool_free(eng->desc_pool, cur, cur_handle);
227 cur_handle = next_handle;
231 dma_pool_destroy(eng->desc_pool);
233 free_irq(eng->irq, eng);
236 /********** Helper Functions **********/
237 int count_descriptors_available(struct kpc_dma_device *eng)
240 struct kpc_dma_descriptor *cur = eng->desc_next;
242 while (cur != eng->desc_completed) {
250 void clear_desc(struct kpc_dma_descriptor *desc)
254 desc->DescByteCount = 0;
255 desc->DescStatusErrorFlags = 0;
256 desc->DescStatusFlags = 0;
257 desc->DescUserControlLS = 0;
258 desc->DescUserControlMS = 0;
259 desc->DescCardAddrLS = 0;
260 desc->DescBufferByteCount = 0;
261 desc->DescCardAddrMS = 0;
262 desc->DescControlFlags = 0;
263 desc->DescSystemAddrLS = 0;
264 desc->DescSystemAddrMS = 0;